Published bi-annually by the The 3-D Architecture of the Nankai

In This Issue:Science Article

Nankai Trough ..................... 1-5

From the MARGINS Chair ...... 6-7

RCL Workshop 2006 .................. 7

Data Management

Status ..................................... 8-9

Non-marine data ...................10

MARGINS Lecture Program .....11

MARGINS Event Response . 12-13

Workshops and Special Sessions

RCL at NMES ..........................14

IBM Mini-Workshop .............15

Education and Outreach ... 16-17

Steering Committee Mtg.... 19-20

MARGINS Office Update ..........20

IMEDL Publication ....................21

Related Programs ......................22

Funded Programs 2005 ..... 24-28

Contact Information .................31

Published bi-annually by the

MARGINS OfficeWashington University in St. Louis

1 Brookings Drive, CB 1169

St. Louis, MO 63130 USA

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The 3-D Architecture of the Nankai Trough

Accretionary Wedge and the Development

of the Seismogenic ZonePerspectives on 3-D Seismic Reflection Profiling in Academia

Nathan Bangs1, and the Nankai 3-D Working GroupNankai 3-D working Group: Tom Shipley1, Greg Moore2, Casey Moore3, Sean

Gulick1, Shin’ichi Kuramoto4, Yasuyuki Nakamura5, and Jin-Oh Park6

1University of Texas at Austin, Institute for Geophysics, 2University of Hawaii, Manoa, 3University of Califor-nia, Santa Cruz, 4CDEX, JAMSTEC, 5Ocean Research Institute, Tokyo University, 6IFREE, JAMSTEC

Introduction

Using the R/V Maurice Ewing in 1999,we acquired a large volume of 3-D seis-mic reflection data along the Murototransect of the Nankai Trough subduc-tion zone (Fig. 1) as part of the MAR-GINS Seismogenic Zone (SEIZE) Initia-tive. Subduction zones such as the NankaiTrough are responsible for the world’slargest and most destructive earthquakesand tsunamis, as was recently exhibitedin the Dec. 26th, 2004 M

w 9.3 Sumatra

event that produced a devastating tsu-nami and the loss of ~300,000 livesaround the Indian Ocean. The primarygoal of our Nankai 3-D seismic experi-ment was to image the plate-boundarythrust fault system in order to map theproperties of the fault from the trenchdown into the subduction zone to the up-dip end of the seismogenic zone. Thissegment of the plate boundary spans thetransition from aseismic-to-seismic slip,where substantial fault zone propertychanges occur as the conditions forseismogenesis develop (Moore andSaffer, 2001). The 3-D seismic data al-

low us to quantify the physical proper-ties of the fault across this transition. Wealso imaged the structure of the accre-tionary wedge in 3-D in order to under-stand the architecture of this margin fromthe deformation front to the older, morecohesive portion of the prism that over-lies the seismogenic zone.

While the experiment began almostsix years ago, we have invested the ma-jority of that time processing the data tomaximize the image quality of the 3-Dvolume. This effort was an experimentto apply industry-style acquisition andprocessing capabilities to image a vol-ume of the Nankai margin within an aca-demic program. In the four yearsfollowing the data acquisition, we suc-ceeded at the University of Texas (UT)and the University of Hawaii in process-ing and analyzing the largest 3-D datavolume in academia using 3-D prestackmigration for the first time in an academicprogram. This migration produced high-quality images with the most extensiveview of subsurface structures and physi-cal properties seen in a subduction zoneto date. However, the complex structuresof the accretionary wedge complex andthe steep seafloor in this setting can causedistortions in the wavefield that cannotbe corrected with prestack time migra-tion. Sophisticated 3-D depth imagingtechniques can correct wavefield distor-tions from laterally varying seismic ve-locities and we pursued these techniquesto produce the best possible images fromthese data. Because the level of effort andthe computational power were beyondour capabilities at UT, we contractedParadigm Geophysical to conduct a 3-Dprestack depth migration. In this article,we present prestack migration images tointerpret the architecture of the Nankai

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Figure 1: Location and tectonic setting of the1999 3-D seismic survey. Rectangle south ofShikoku is the 3-D survey area.

MARGINS Newsletter No. 14, Spring 2005 Science Article

Trough subduction zone along theMuroto transect. This article is a sum-mary of both some of the results pub-lished thus far and new results based onthe new 3-D prestack depth migratedimages.

The 3-D Seismic Experiment

The goal of 3-D seismic reflection im-aging is to adequately sample thewavefield and reconstruct the subsurfacestructure in 3-D. One of the greatest chal-lenges for 3-D seismic reflection survey-ing is adequate areal coverage to assurethe wavefield sampling has sufficient ap-erture in both inline and cross line direc-tions, and, simultaneously, close spatialsampling to avoid aliasing. With a fixedtime window for data acquisition and theEwing’s single seismic recordingstreamer, we maximized areal coveragewith the closest possible line spacing toachieve the highest image quality. Anadditional challenge for this experimentwas that the survey area extended acrossthe strong Kuroshio Current, whichranged from 0 – 4 knots perpendicular tothe shooting line direction and affectedreceiver position and spatial sampling.The limitations in these data require thatconsiderable effort and the best tech-niques possible for post-acquisition pro-cessing be applied to produce the bestpossible images.

We designed the seismic survey toimage the subduction thrust from thetrench into the seismogenic zone (Figs.1 & 2). We acquired 81 lines, each 80

km long, with a single 6 km streamer. Thelines are 100 m apart and thus cover an 8x 80 km area (Fig. 1). We used a Racaldifferential GPS (Global Positioning Sys-tem) navigational system for determin-ing ship’s position, shot spacing, andtail-buoy location. The seismic sourcewas a tuned 14-airgun, 70 L (4273 in.3)array with sizes from 1.3–10.5 L (80–640in.3). This source is capable of resolvinglayers of ~10-12 m thickness. The re-ceiver array was the R/V Maurice

Ewing’s Syntrac 6000 m streamer with240 channels at 25 m spacing. Data wererecorded at 2 ms sampling for 12 s.Streamer depth was maintained with con-trol birds every 300 m and position re-constructed from 11 compasses spacedat 600 m and verified using the availabletail-buoy differential GPS data.

During the 3-D acquisition cruise weconducted 2-D processing of each line.Following acquisition we conducted avelocity analysis, stack, and 3-D post-stack time migration. Unfortunately thepost-stack time migration revealed det-rimental aliasing effects due to the com-promise between spatial sampling and

aperture. This was partially remedied byreplicating nearby traces to fill in miss-ing data and then reprocessing, but thismethod also introduced smearing effects.Some success was achieved with inter-polation of missing traces and migratingthe 3-D volume a third time, but it be-came apparent that post-stack migrationwould not produce images significantlybetter than the 2-D processed data.

At the University of Texas, we con-structed three-dimensional seismic im-ages of the volume with 3-D prestacktime migration. Excellent images of thedécollement resulted when (1) each of the~34 million traces were individually mi-grated in three-dimensions by usingKirchhoff prestack time migration withthe Geodepth processing software pack-age and (2) migrated traces common to50 x 25 m bins were stacked into an im-age volume of 181 lines with 50 m cross-line spacing. Binning and streamerfeathering produce 181 lines from theoriginal 81 lines.

Paradigm Geophysical in Houstonconducted a similar process using 3-Dprestack depth migration. Followingsome additional preconditioning of theprestack data that included multiple sup-pression, deconvolution, and shot equal-ization, two iterations of velocity analysispreceded the prestack depth migration.In the process of determining migrationparameters, we discovered that problemsdue to spatial aliasing required that werestrict the migration aperture to a nar-row limit of 1,000 m, while target struc-

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Figure 2: Seismic line 260 from the 3-D seismic data volume. These data were processed with 3-D prestack depth migration. Rectangularboxes outline portions of the data shown in Figures 3 & 4.

The goal of 3-D seismic

reflection imaging is to

adequately sample the

wavefield and reconstruct the

subsurface structure in 3-D.

MARGINS Newsletter No. 14, Spring 2005

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tures such as faults required larger aper-tures of >4,000 m for proper imaging. Weused a compromise aperture of 2,000 m,but discovered that image quality couldnot be improved throughout the entiredata volume with the same migrationaperture. We chose to maximize the im-age quality with prestack depth migra-tion in the large thrust-slice zone (Fig.2), which was not imaged well with theprestack time migration, and relied onprestack time migration for the frontalimbricate thrust zone (Fig. 2).

Results

Décollement physical properties: Ourgoal to map the physical properties of thedécollement from the trench into theseismogenic zone was achieved with theprestack time migrated data. These re-sults have been published in Bangs et al.(2004) and are only summarized here. InBangs et al. (2004) we mapped an 8 x 50km area of the décollement and revealedboth along strike and down-dip variationin seismic reflection amplitude of thedécollement from the trench to the up-dip edge of the seismogenic zone. OceanDrilling Program (ODP) Legs 190 and196 determined that the seismic reflec-tion is caused by an increase in porosityacross the fault zone due to delayed con-solidation of the underthrust sediment(Moore et al., 2001c). The high-ampli-tude reversed polarity reflection mappedacross the drill site is consistent with thedrilling observations and suggests that thedécollement amplitude can be used tomap the down-dip extent of theunderconsolidated underthrust sediment,and thus the presence of fluid-rich areasof the fault with potential overpressures.These data revealed that the fluid-richareas of the fault extend down-dip to ~35km and were not found in areas fartherdown-dip. The down-dip extent of thefluid-rich décollement terminates coin-cidentally at the up-dip edge of theseismogenic zone defined by both rup-ture areas of recent megathrust events andmicroseismic events (Obano, et al.,2001). It also coincides with a downwardstep in the décollement and a zone ofunderplating that suggests a downward

migration of the décollement to deeperslip surfaces with lower shear stress. Bothof these events are interpreted to be a re-sult of sediment consolidation and lossof fluid within the fault zone that ismapped by seismic reflections from our3-D volume.

The 3-D subduction zone architec-ture: There are two distinctive zones thatcomprise the Nankai accretionary com-plex along the Muroto transect: the fron-tal imbricate thrust zone and the zone oflarge thrust sequences (Moore et al.,2001a). The seismic images from inter-polated post-stack (Gulick et al., 2004)and prestack time migration allowed usto examine the frontal thrust system thatcomprises the seaward-most 30 km of theaccretionary wedge (Fig. 3a). These im-ages reveal a complex deformationalstructure of imbricate thrusts that soleinto the décollement and allow thicken-ing and shortening of the accretionary

wedge as observed on previous seismicimages of accretionary wedges from theNankai Trough and elsewhere (e.g.,Moore et al., 1990; Gulick et al., 1998;Bangs et al., 1999). Considerable addi-tional internal deformation is well imagedin the clarity of the 3-D images. This de-formation includes numerous conjugatethrusts that have opposite dip to the mainthrusts, and small scale folds (Fig. 3a).The thrust system has a regular thrustspacing of ~ 1 km and thickens a strati-graphic sequence that had ~ 1 km initialthickness (Gulick et al., 2004).

In addition to the new clarity of thedown-dip images, we were also able toextend our look and interpret the thrustsystem along strike across the 8 km ofthe 3-D survey area. Gulick et al. (2004)describe the architecture of the frontalthrusts in 3-D as a series of overlappingfault segments that terminate along strikeand maintain an orientation that strikes

Figure 3: a) Line 230 showing the imbricate thrust zone across the seaward-most 18 km ofthe accretionary wedge. These data are results from 3-D prestack time migration. Discretefaults are clearly recognizable, two of which are traced (red lines) and labeled correspondingto Figure 3b. b) Perspective view of the seafloor bathymetry showing the frontal thrust ridgesand the corresponding thrusts. Numbers and red lines mark the surface outcrops of discretefaults (from Gulick et al., 2004).

MARGINS Newsletter No. 14, Spring 2005 Science Article

perpendicular to the convergence direc-tion (Fig. 3b). Simultaneously these faultsproduce ridges (Fig. 3b) that follow abroad margin trend that strikes obliqueto the convergence direction and lead intothe Tosa embayment to the east, anembayment caused by a subducted sea-mount (Kodaira et al., 2000). At the land-ward edge of the imbricate thrust zone,out-of-sequence thrusts begin to over-print the faults developed during frontalaccretion and thus alter the wedge geom-etry for the areas upslope from the im-bricate thrust zone (Fig. 2).

In contrast to the zone of imbricatethrust slices, the zone of large thrust sliceshas a distinctively different architecture(Fig. 4a). The large thrust-slice zone has1) thrust slices ~ 1.5 - 2 km thick, ap-proximately twice as thick as the frontalthrusts, 2) ~10 km long thrust spacing,which is an order of magnitude longerthan the frontal thrusts, and 3) throws of~ 5 km, versus 0 – 200 m for the frontalthrusts.

The intriguing questions regardingthese observations ask what caused thesignificant change in the wedge architec-ture? Coincidentally the up-dip limit ofthe seismogenic zone roughly correlateswith the change in wedge architecture.Is there a causal relationship or is it sim-ply a coincidence?

Initial prestack time migrations didnot reveal details sufficiently for us to beable to resolve the fault structure and de-termine the major and minor fault sys-tems within the large thrust-slice zone.However, the 3-D prestack depth migra-tion improved the images of the largethrust-slice zone because they were ableto accommodate distortions in thewavefield from the locally steep seafloorand underlying structures (Fig. 4a). The3-D prestack depth images allowed us todetermine the faults and their along strikecontinuity, and accurately interpret thefault geometry. Fig. 4a reveals a seriesof primary thrusts that accommodate themajority of shortening (e.g., Faults 1, 3and 6). These define the major thrustpackets that are themselves thickened bysecondary, shorter and steeper faults thatconnect the primary thrusts (e.g., Faults

2, 4, and 5) and thicken the thrust pack-ets. The architecture of the large thrust-slice zone has not evolved from thefrontal thrust architecture, instead it ini-tiated with significantly different frontalaccretion geometry.

Finally, the cross line geometry of thethrusts within the large thrust sliceschanges sharply along strike. Althoughdifficult to depict in the 3-D perspectiveview of Figure 4b, the faults dip signifi-cantly (7-8°) in the cross line directionthroughout the middle of the survey; thatis, the faults do not strike parallel to the

local trend of the accretionary prism. Thischange in trend along-strike contrastsstrikingly with the prism-parallel geom-etry of structures in the imbricate thrustzone.

We speculate that the large thrust-slicezone and the frontal imbricate zone wereconstructed during significantly differentaccretionary conditions before and afterthe subduction of a small seamount (Fig.5). The large thrust-slice zone requires athicker trench sediment section than iscurrently in the trench, which could haveaccumulated between the trench and the

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Figure 4: a) A portion of Line 270 showing the large thrust-slice zone. These are results from3-D prestack depth migration. Red lines show the main thrust sequences, and black linesmark thrusts that thicken the main thrust sequences. Numbers correspond to thrust surfacesin Fig. 4b. b) Perspective view of the large thrust-slice zone showing the continuity of thrustsin the strike direction.


elevated crust of a seamount. We specu-late that the thrust geometry prior to sea-mount subduction would have involvedlonger, more widely spaced thrusts thancurrently observed at the trench becauseof the thicker (and possibly sandier withmore turbidites) incoming sediment sec-tion.

Interestingly, Fig. 2 images a largestructure as part of the subducting oceancrust that we interpret to be a seamount.This, however, is not the seamount re-sponsible for Tosa Bae mentioned above,which is larger, farther east, and liesdeeper within the subduction zone. ODPLeg 190 drilling determined that the largethrust-slice zone was accreted within thelast 2 m.y. (Moore et al., 2001b). Assum-ing a subduction rate of 4 cm/yr, the sea-mount we image (Fig. 2) would havebeen located up-dip 60 km at the currentdeformation front 1.5 ma, which is rea-sonably good timing for deposition ofthick trench sediment between the accre-tionary wedge and the seamount, fol-lowed by accretion of the largethrust-slice zone (Fig. 5). The subduction

of a seamount is also consistent with thedeflection of structures observed in thecross line profiles of the large thrust-slicezone. We speculate that it is this sub-ducted seamount that caused the devel-opment of the large thrust-slice zone.

Conclusions

The transition from seismic toaseismic slip is coincident with the lossof fluids along the décollement, thedownward step of the décollement, andthe change in accretionary wedge archi-tecture from the zone of imbricate slicesto the large thrust-slice zone. The largethrust-slice zone may have beenemplaced by an episodic event involv-ing the subduction of a modest sized sea-mount rather than through anevolutionary process. The large thrust-slice zone and its locally steep slope mayserve to increase loading on thedécollement and accelerate fluid lossalong the décollement, and hence con-tribute to conditions that generate earth-quakes.

Future NanTroSEIZE 3-DSeismic Imaging

While the Muroto transect 3-D seis-mic project provided excellent images ofthe megathrust system and the structureof the accretionary wedge, it offered fewopportunities for a deep drilling target forthe IODP Nankai Trough SeismogenicZone Experiment (NanTroSEIZE).NanTroSEIZE plans to drill through theplate-boundary thrust to sample the faultzone at the up-dip edge of theseismogenic zone in order to determinerock properties and monitor fault zoneconditions. These data proved to havefew good targets for this project becausethe up-dip edge of the seismogenic zoneis at the maximum possible drilling depthfor the Chikyu riser drill ship in waterdepths less than 2500 m, in which theriser system can be used. Furthermore,recent reexamination of the 1946 M

w 8.1Nankaido event showed there was mini-mal slip along the shallow décollementalong the Muroto transect. Both of theseresults were unknown during the designof the Muroto 3-D data acquisition andled to relocation of the NanTroSEIZEdrilling to the Kii peninsula/Kumanobasin transect to the east. We are currentlyplanning a new 3-D seismic reflectionproject, jointly funded by NSF-IODP andJapanese sources, to acquire a 3-D datavolume for imaging the subduction zonefault systems and for engineering, safetyand well design for non-riser and riserdrilling as part of the NanTroSEIZE drill-ing project. The new 3-D data acquisi-tion will begin in late spring 2006.

ReferencesBangs, N. L., T. H. Shipley, J. C. Moore, and

G. F. Moore, 1999. Fluid accumulationand channeling along the northern Bar-bados Ridge décollement thrust, J.Geophys. Res., 104, 20, 399 - 20,414.

Bangs, N. L., T. Shipley, S. Gulick, G. Moore,S. Kuromoto, and Y. Nakamura, 2004.Evolution of the Nankai Troughdécollement from the trench into theseismogenic zone: Inferences from three-dimensional seismic reflection imaging,Geology, 32, 4, 273 –276.

Figure 5: Cartoon showing three stages in the development of the large thrust-slice zone andimbricate thrust zone with the subduction of a small seamount. Initially (top panel) theseamount approaches the trench and causes a thick trench section, potentially comprised ofsandy turbidites, to accumulate. Next (middle panel) broadly spaced thrusts develop andform the large thrust-slice zone and the trench wedge thins. Continued shortening of thelarge thrust-slice zone area and frontal accretion produce the geometry observed today (bottompanel). see “3-D” cont. on page 28

Interpretation

Accretion of long trench sections to form the large thrust zone

Current geometry

Subducting

seamount

Older accretionary wedge

5 km

Accretion of short trench sections to form the imbricate thrust zone


Imbricate thrust zone

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From the MARGINS Chair - Spring, 2005Julie Morris, Dept. of Earth and Planetary Sciences, Washington University, St. Louis, MO 63130, USA

E-mail: [email protected]

From the Chair

Although it’s hard to believe, I’m alreadyhalfway through my three-year term asChair of the MARGINS Steering Com-mittee (MSC) and Office. MARGINS hasmatured considerably during that time,which provides the focus for this Chair’sReport.

MARGINS Data Management

The rapid pace of improvement inMARGINS data archival and manage-ment has been remarkable. Two articlesin this newsletter testify to overall ad-vances in MARGINS data management,and to increasing efforts to developmetadata and data server formats that arefriendly and efficient for land-based ex-peditions. Most important to the successof the data management system (DMS),however, is the cooperation of you, thefunded investigators. NSF fundingthrough MARGINS carries with it anobligation to archive the metadata within60 days of the end of the expedition andto archive the data itself within two yearsof collection, with exemptions arrangedby discussion with your NSF programofficer. To help the MARGINS DMSdeliver on its research and educationalpromise, members of the DMS and theMARGINS Office will be in touch peri-odically with nice reminders and inquir-ies about the public availability of yourdata. NSF, of course, is the ultimate ar-biter; they can decline to accept new pro-posals if you are seriously out ofcompliance with the NSF data policy onprior efforts. In preparing your nextMARGINS proposal, remember thatNSF requires you to explicitly state a planfor data archival and sharing.

MARGINS DistinguishedLectureship Program

I’m very pleased about the superbquality of the four scientists who will bethe first, but not the last, cohort of MAR-GINS’ Distinguished Speakers. Repre-senting each of the four initiatives, Drs.

Neal Driscoll, Terry Plank, SusanSchwartz and Joann Stock will give botha public lecture and a technical talk in 3-4 colleges during the spring of 2006. Ouremphasis will be on matching speakerswith colleges or universities that are notalready involved with MARGINS re-search, including those not grantingPh.D. degrees. Our hope is to excite un-dergraduate and young graduate studentsand their teachers about the research andopportunities available through MAR-GINS. See page 11 for more information.

Status of the Initiatives

Members of the MSC assess the sta-tus of the initiatives at each meeting inorder to evaluate progress made and gapsremaining in the implementation of theScience Plans. As MARGINS moveswell into the second half of its originaldecadal program, and with a recommen-dation from the NSF-MARGINS ReviewCommittee to consider a second decadalprogram, the MSC is also beginning todiscuss possibilities for a longer-termfuture.

S2S

Several proposals have now beenfunded for the Waipaoa region of NewZealand; the first two cruises sailed ear-lier this year. A MARGINS S2S meet-ing/workshop will be held in conjunctionwith the New Zealand Marine ScienceMeeting <http://www.vuw.ac.nz/marineconference2005> in August to fa-cilitate synthesis and planning. Addi-tional work has been funded in NewGuinea (NSF Awards 0505987 and0504465, Fagherazzi and Overeem), withan emphasis on modeling the tidallydominated Fly River delta, the “missinglink” between current work on the floodplain and in the Gulf of Papua. Initialplanning has begun for a S2S Theoreti-cal and Experimental Institute (TEI) inthe summer of 2006, with Bill Dietrich,Rudy Slingerland and John Milliman

heading the group of conveners. The pro-posed theme of “Teleconnections be-tween Source and Sink in SedimentDispersal Systems” would consist of amoving field trip down a S2S system. Theidea is that daily keynote presentations,selected thematic poster sessions, andmini-workshops will alternate with fieldtrips that illustrate key processes andproducts, moving down the sedimentpathway. One goal of the TEI is to fosterinteractions among theoreticians (mod-elers), experimentalists, and fieldobservationalists as well as oceanogra-phers, tectonicists, and geomorpholo-gists.

RCL

A fairly large body of work has beenfunded to date in the Gulf of California/Salton Trough region, and work is pro-gressing well. A synthesis workshop willbe held Jan. 9-13, 2006, in Ensenada,Mexico (see advert, page 7) to (1) sum-marize the current research status in theGulf of California – Salton Trough focussite; (2) synthesize observations, resultsand related theoretical efforts; and (3) usethis information to identify gaps inknowledge and suggest possible direc-tions for future research. The three daysof meetings will be combined with a two-day field trip to view Plio-Pleistocenelow-angle normal faults in the LagunaSalada area. The meeting conveners areRebecca Dorsey, Raul Castro, JohnFletcher and Daniel Lizzaralde. For theRed Sea region, the MARGINS programofficers at NSF have indicated their will-ingness to consider proposals for workin the area, in contrast to the two previ-ous years. This in part reflects the suc-cess of a EuroMARGINS cruise in thecentral Red Sea early this year. It alsoreflects the strong sense of the MSC andNSF-MARGINS Review Committee thatthe Red Sea is the prime location forstudying active rifting of cratonic conti-nental lithosphere in a style analogous to


that of the rifted N. Atlantic margins. It’spossible that MARGINS may ultimatelyabandon the Red Sea focus site if itproves logistically impossible to get aca-demic US ships into the region. However,with good working relationships withSaudi Arabian and Egyptian scientists,and the successful EuroMARGINScruise, it makes sense to us to pursue thisavenue a next step further. In the mean-time, a proposal has been funded(0505812, Nyblade) to use Saudi seismicdata and PASSCAL data from an Ethio-pian deployment to study the seismicstructure of the crust and upper mantlein the northern and Central Red Sea.

SEIZE

Rapid progress is being made towardriser drilling in the Nankai focus site, in-cluding a planned (2006) joint US-Japa-nese 3-D seismic survey in the Kumanobasin off the Kii Peninsula, the target areafor riser drilling (See Bangs et al., p. 1).An extensive synthesis of seismic reflec-tion data from the Nankai Trough, fundedin the last cycle (0505789, Moore), willprovide a regional structural/stratigraphicframework for both riser and riser-lessdrilling in the Nankai seismogenic zoneas well as insight into the effects of pro-cesses such as seamount subduction/col-lision. Work also continues in the CostaRica region, including high resolutionseismic profiling in Nicaraguan lakes toinvestigate models of forearc deforma-tion due to oblique subduction (0440143,McIntosh), and the analysis of P to Swave converted phases from seismom-eters directly above the subducting slabto determine velocity structure across theoceanic Moho and its relation to the hy-dration of the oceanic lithosphere(0440396, Schwartz). Publication of theMARGINS book, The Seismogenic Zoneof Subduction Thrust Faults, edited byT. Dixon and J.C. Moore, is expected inSpring of 2006 (see page 18 for a list ofcontributed papers). With the proposalsfunded to date, many of the large, expen-sive marine geophysical surveys requiredby the SEIZE science plan are underway,and planning for drilling the seismogeniczone is well advanced. The MSC notes

see “Chair” continued on page 29

the need for improved and ultimately in-tegrated thermal-hydrological-chemicaland deformational modeling. Also im-portant will be experimental and theoreti-cal studies that speak to earthquakenucleation, propagation and arrest.

SubFac

In preparation for the 2004 NSF Re-view of MARGINS, the MSC noted thatmany of the large expensive geophysicalstudies needed to establish the frameworkfor SubFac studies have been funded,leaving just a few gaps. Last year’s fund-

“Lithospheric Rupture in the Gulf of California –

Salton Trough Region”

MARGINS Rupturing Continental Lithosphere Workshop

Ensenada (Mexico), January 9-13, 2006

Convened by: Rebecca Dorsey (Univ. of Oregon, USA), Raul Castro

(CICESE, Mexico), John Fletcher (CICESE, Mexico) and Daniel Lizarralde

(WHOI, USA)

A MARGINS-sponsored workshop on “Lithospheric Rupture in the Gulf of Califor-

nia – Salton Trough Region” will be held January 9-13, 2006, in Ensenada, Mexico.

The workshop will focus on recent research on lithospheric extension, crustal de-

formation, seafloor spreading, magmatism, basin formation, and upper-mantle pro-

cesses that have operated through time to shape this active oblique-rift system.

Insights from theoretical modeling and studies of other rifted margins will provide

additional perspective. Emphasis will be placed on integration of data from diverse

disciplines including structural geology, geophysics, geochemistry, petrology, vol-

canology, stratigraphy, and paleontology. The main goals of the workshop are to:

(1) summarize the current status of geophysical and geological research in the Gulf

of California – Salton Trough focus site; (2) synthesize observations, results and

related theoretical models in a focused setting that promotes open exchange and

development of ideas; and (3) use this information to identify gaps in knowledge

and suggest possible directions for future research.

The workshop will include two days of oral presentations and posters, a two-day

field trip to view Plio-Pleistocene low-angle normal faults in the Laguna Salada

area, and a final day for overview, synthesis, and summary of workshop outcomes.

Speakers will be asked to represent their respective research groups in overview

talks that emphasize the integration and synthesis of diverse data sets. Presenta-

tions and results will be disseminated after the workshop via an active web site to

be maintained by the MARGINS Office. A volume of related papers, edited by the

conveners, will be published as part of the “MARGINS Theoretical and Experimen-

tal Earth Science Series.”

Interested researchers from all countries should visit the meeting web site (http://

www.rcl-cortez.wustl.edu/) and submit an online application by August 15, 2005.

Post-docs and senior graduate students are encouraged to apply. Funding from

NSF is expected to cover a significant fraction of travel and accommodation costs

for US participants.

ing of a magnetotelluric study in the Izu-Bonin-Mariana (IBM) focus site (com-mencing Dec. 2005) and of an activesource crustal structure study of the CostaRican volcanic arc, back-arc anddowngoing slab (now underway) fillmost of those major gaps. In both IBMand Central America, data from bothlarge passive-source and active-sourceexperiments are beginning to be ana-lyzed, and show much promise for im-aging the crust and upper mantle of bothfocus sites. SEIZE projects in Costa Rica


DMS: MARGINS

Applications Data Partners Explore Further

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Data Link

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Antarctic Bathymetry

MARGINS

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UTIG Processed Seis

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Meetings & Reports

Acknowledgements

Statistics & Holdings

MARGINS Data Portal

This page provides access to cruise information and data collected during

MARGINS funded projects. Learn more about this web site by browsing

the What's New page, and reading other Project Related Documents.

You can download forms to document your field program.

Use GeoMapApp to view the global topography database, create and

download custom maps and grids as well as multibeam ping files.With

GeoMapApp you can also view and explore trackline gravity and

magnetics data, geochemical data from PetDB, seismicity, and seismic

reflection profiles.

Use Data Link to search for a cruise or data type of interest by keyword or

geographic region.

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Status Report on the MARGINS Data Management SystemAndrew Goodwillie and the mgDMS team, Lamont-Doherty Earth Observatory

An effective data management system -one that provides convenient access toand dissemination of diverse and multi-resolution data - is essential for the suc-cess of MARGINS. Such a system helpsto ensure timely sharing of informationto the broader community, facilitate in-tegration of the suite of studies carriedout within each Focus Site, and enablecomparisons between sites. To meet thesedata-sharing needs we are developing anintegrated data management system,called mgDMS, to provide basic cata-loguing and retrieval for data collectedunder the MARGINS Program<www.marine-geo.org/margins>. Thedata system is fully integrated with simi-lar efforts for Ridge2000 as well as data-bases for seismic reflection data, andbathymetry from the global ridge system(RidgeMBS) and the Southern Ocean(AntarcticMBS). The aim of our effort isto develop an easy-to-use and content-rich resource to facilitate geoscience re-search having global reach.

Metadata - information describingdata - provide the backbone of the MAR-GINS data system. The metadata cata-logue serves basic information about fieldprograms, geophysical and sample datainventories, navigation and sample/sta-tion locations, and so on. In addition tometadata, the primary data sets hostedlocally include key data of broad rel-evance such as bathymetry, as well ashigh-priority derived data products, anddata types for which no web-accessibledigital repository currently exists. Fordata that reside within an existing na-tional repository such as geochemicaldata in PetDB and deep submergencedata at WHOI, data access is providedby linking to these sites.

Three tools for accessing data in theMARGINS data system are provided atwww.marine-geo.org/margins (Fig. 1):Data Link, a web interface search pagethat allows users to query the metadatacatalogue by parameters such as data

type, location, Principle Investigator,field program name, and dates; CreateMaps and Grids, a web-based tool forcreating grids and maps from our globalDEM (bathymetry plus land) database;and GeoMapApp, a map-based interfacethat allows dynamic exploration of mul-tiple global data types. More informationon these tools and on the structure of thedata system is provided in Carbotte et al.,2004 and at our web site, www.marine-geo.org.

MARGINS Data Holdingsand Access

Cruise information (metadata) for anumber of MARGINS and MARGINS-related field programs has been submit-

ted to mgDMS and is now accessiblethrough the database (Fig. 1). These da-tabase entries include searchable listingsof field parties, projects associated witheach cruise, and links to relevant NSFFastlane award pages. Navigation infor-mation is included for the ship, as are thelocations of samples and stations. An in-ventory of data types collected on thecruise and their contact person is pro-vided, as are links that allow the avail-able data to be downloaded. Submittedcruise reports and links to cruise orproject web sites are also given. Pleasenote that data files submitted to the data-base are restricted with a proprietary holdunless immediate release is approved bythe PI.

Figure 1: Home page for the MARGINS database.

Data Management


Bathymetry

Bathymetry data are of particular im-portance for the MARGINS Focus Sites.They provide an integrating frameworkfor the range of multi-disciplinary stud-ies carried out at each site, as well as afundamental data set for understandinggeological processes. Although not allmulti-beam bathymetry data for allMARGINS cruises to date have beensubmitted to the database, we have com-piled all publically-available multi-beambathymetry in the Focus Sites. An ultra-high resolution (4 m) Simrad EM3000bathymetric grid for portions of the PapuaNew Guinea area provided by Dave Naar(University of South Florida) is alsoavailable (found under the Hi_Res_Grids option in the pull-down Placesmenu).

Data Visualization

GeoMapApp, the data visualizationtool integrated with the MARGINS datasystem, provides access to currently-available bathymetry data for each Fo-cus Site as well as to historical databasesof trackline underway geophysical data,single-channel seismics, and geochemi-cal data from PetDB. Options are pro-vided for the generation of downloadablecustom maps and for simple data manipu-lation tasks such as the digitization of pro-files. GeoMapApp is being extended toenable users to easily import their owndata. At present, both Excel spreadsheetsand ASCII data tables can be importedthrough the Import Data option underthe Database tab.

The Past Year

Behind the scenes, the inner workingsof the data system have undergone amajor overhaul for improved expansionand flexibility. The MARGINS data sys-tem web page, www.marine-geo.org/margins, has been modified to include up-front links to each of the seven FocusSites (Fig. 1). Metadata for seven MAR-GINS-funded cruises have been receivedand ingested into the data system. High-resolution bathymetry for part of PapuaNew Guinea and multi-beam bathymetry

from some MARGINS cruises in the Gulfof California, IBM, Central America, andNew Zealand Focus Sites have beenmerged into the global Digital ElevationModel (DEM). Historical multi-beamdata for non-MARGINS cruises that passthrough the Focus Sites were obtainedfrom the National Geophysical Data Cen-ter and added to the DEM. Collaborationwith ODP has continued: access and vi-sual exploration of DSDP data are nowavailable through the GeoMapApp inter-face (found via the Under Developmenttab).

Based upon feedback from PIs dur-ing the 2004 field season, the packet ofelectronic metadata forms for marineoperations was much revised. The cur-rent version is available at www.marine-geo.org/data_forms.html. In January2005, a subgroup of the MARGINS Of-fice and Steering Committee came toLamont for a meeting to discuss the in-clusion into the data system of MAR-GINS land-based field programs (see p.10). As a result of the guidance receivedat that meeting we are developing apacket of electronic metadata forms forterrestrial operations.

Representatives from the mgDMSgroup gave presentations at each of theMARGINS Steering Committee meet-ings over the last year. At Fall AGU,2004, the MARGINS data system washighlighted at the MARGINS townhallmeeting and at the mgDMS booth in theExhibition Hall. EOS published an articleon the data system (Carbotte et al., 2004).

More detail on this past year’s workis under What’s New on the MARGINSdata system web page: www.marine-geo.org/margins.

Future Work

In the coming year, we will continue

to actively solicit contributions for eachMARGINS Focus Site of cruise and landprogram information and we will con-tinue to add historical data. We are seek-ing cruise reports and field data, as wellas the derived data such as bathymetricgrids that are often of most use to thebroader community. Data submitted tothe database are restricted with a propri-etary hold until public release is approvedby the PI. The user interface for theMARGINS data system will be improvedand we will build new links with exter-nal MARGINS-related databases includ-ing UNAVCO and IRIS.

For future field programs we ask sci-entists to use our updated cruise and ter-restrial electronic metadata form packets,available at: www.marine-geo.org/data_forms.html. As per MARGINS DataPolicy <www.margins.wustl.edu/DataPolicy.html>, scientists are asked tosubmit their field program information,sample inventories, and navigationwithin 60 days of their program ending.Submission of data files is also to followthe Data Policy requirements.

The Need for CommunityInput

Development of the database as a re-source for MARGINS science relies onthe active involvement of the MARGINScommunity, both in submitting their fieldprogram information and data, and inidentifying additional relevant historicaldata or derived data products. We aregrateful to all who provided cruise infor-mation and data over the past year.

Community feedback is essential inour continued efforts to develop theMARGINS database. We encourage ev-eryone to try out the system and send uscomments on any aspects, especially us-ability and content.

ReferenceS.M. Carbotte, R. Arko, D.N. Chayes, W.

Haxby, K. Lehnert, S. O’Hara, W.B.F.Ryan, R.A. Weissel, T. Shipley L.Gahagan, K. Johnson, T. Shank, New in-tegrated data management system forRidge2000 and MARGINS research, EOSDec 21, vol 85, 553, 559, 2004.

Development of the database

as a resource for MARGINS

science relies on the active

involvement of the MARGINS

community.


Handling of Non-marine Data and Metadata in the

MARGINS Data Management SystemLamont-Doherty Earth Observatory, January 10, 2005

mgDMS group are now developing asuite of non-marine metadata forms tobe trialed later this year.

• Data Policy compliance: Without neartotal compliance under NSF andMARGINS Data Policy, the datamanagement system will be unable tofully serve the needs of the commu-nity. Over the coming year the MAR-GINS Office and mgDMS group willcontact PIs directly to confirm datatypes collected under NSF-MAR-GINS, inform them of their DataPolicy standing and solicit feedback.

Through this meeting, and others likeit, the mgDMS group are working to addthe flexibility and tools most needed bythe communities served. Their efforts willfacilitate PI Data Policy compliance, andprovide an indispensable tool for the con-tinental margin research community.

The MARGINS Steering Committee,aided by the MARGINS Office, is work-ing to establish MARGINS communitypriorities for data management. Membersof the community wanting to ensure thatspecific issues are considered may do soby contacting the MARGINS Office or aSteering Committee member (see p. 31).

-PW

In early January a data management sub-group of the MARGINS Office andSteering Committee (Geoff Abers, MarkReagan, Pat Wiberg, and Paul Wyer) metwith members of the Marine GeosciencesData Management System (SuzanneCarbotte, Bill Ryan, and Bob Arko),GeoMapApp developer Bill Haxby, andPetrological Database of the Ocean Floor(PetDB) PI Kerstin Lehnert, at Lamont-Doherty Earth Observatory in order tofocus on handling of non-marine data andmetadata in the MARGINS Data Man-agement System (DMS).

The Marine Geoscience Data Man-agement System (mgDMS), of which theMARGINS DMS is a part, was devel-oped to handle cruise metadata. However,all involved recognize the importance toMARGINS science of data collected sub-aerially, so the agenda dealt specificallywith the needs of existing terrestrialMARGINS research and future needsprojected by the MARGINS SciencePlans:• Data repositories: As a designated

portal to all MARGINS data, mgDMSneeds to maintain current metadataproviding sufficient information fordiscovery of all MARGINS data andsamples, whatever their location. The

mgDMS group continues its efforts toestablish metadata and data sharingagreements with other repositories,both in the U.S. and internationally.However, forging such agreements anddeveloping interoperability is timeconsuming, so community feedback onwhich repositories (particularly non-U.S. repositories) host the most criticaldata for MARGINS science andscience planning is essential.

• Unsupported data types: Some MAR-GINS digital data types, particularly inthe terrestrial realm, lack a standardonline repository. Community help isneeded with identification of these datatypes so that the mgDMS group candevelop facilities to serve them.

• Data and metadata retrieval: Non-marine data are structured andaccessed differently, necessitatingreview of the Data Link structure, oneof the interfaces for accessingMARGINS data.

• Non-marine metadata compilation andsubmittal: Metadata submission formsfor non-marine studies need to accom-modate a different range of data typesand data/sample identification methodsto their cruise equivalents. Withassistance from members of theMARGINS Steering Committee the

Changes in NSF-MARGINS Proposal Deadline(and other NSF policy news)

August 1, 2005 is Next DeadlineCurrent and potential MARGINS principal investigators should be aware of some important

updates affecting submission of MARGINS proposals:• NSF has updated the MARGINS Program Announcement with some important changes. The most critical change is that the

annual proposal submission deadline will be August 1 from 2005 on. As before, there will be only one deadline per year.• New guidelines for the MARGINS Postdoctoral Fellowship are being released.• The MARGINS Data Policy has been updated in answer to emergence of the MARGINS Data Management System. Data

obligations for existing principal investigators are not affected, but the PIs will need to refer to the new policy for informationon how and where to submit metadata. Those seeking funding for MARGINS research should refer to the updated policywhen preparing their proposals. The NSF Grant Program Guide <www.nsf.gov/pubs/gpg/nsf04_23/start.htm> containsguidelines for information required in proposals regarding plans for data sharing.

The above documents, along with other MARGINS announcements, are available via the MARGINS Announcementspage: www.margins.wustl.edu/Announce.html.

Data Management


Neal Driscoll:

Source to SinkNeal Driscoll is a Professor of Geology

at the Scripps Institution of Oceanography.His primary interest is in using the sedi-ment record to understand the interactionof tectonic deformation with the evolutionof landscapes and seascapes. His researchhas focused on unconformity generationand stratigraphic development in tectoni-cally active settings; and sediment inputand dispersal in evolving sedimentary ba-sins and along continental margins.

Among his other qualifications, Neal re-ceived the SIO Outstanding Undergradu-ate Teaching Award.Lecture themes: “Reading Earth historyfrom the geologic record.” “Dispersalsystems in actively deforming regions:Papua New Guinea has it all!”

Terry Plank: The

Subduction FactoryTerry Plank’s research in igneous

geochemistry focuses on the study of mag-mas associated with the plate tectonic cycleat both divergent and convergent platemargins. Many of her research projectshave addressed the recycling of materialbetween mantle and crust within the “sub-duction factory.” Recent work focuses onthe volatile content of arc magmas, and the

relationship to slab fluid compositions,mantle melting, and magma evolution.

An Associate Professor and Director ofUndergraduate Studies at Boston Univer-sity, Terry has studied volcanoes in thePhilippines, Central America and the Aleu-tians. She has received the HoutermansMedal from the European Association forGeochemistry, and the Geological Societyof America Donath Medal.Lecture themes: “The effect of wateron mantle melting at subduction zones.”“Recycling within the Subduction Fac-tory.”

Susan Schwartz: The

Seismogenic ZoneSusan Schwartz’s research interests in-

clude the mechanical behavior of theseismogenic zone at subduction margins,the velocity structure of the crust and up-per mantle in plate boundary regions, vol-canic deformation and seismicity, andseismotectonics of the San Andreas faultsystem and Costa Rica. Ongoing and re-cent field projects include imaging of theseismogenic zone across Costa Rica andthe Middle America Trench using geod-esy and seismology.

Susan is a Professor of Earth Sciencesand Director of the Center for the Study ofImaging and Dynamics of the Earth at theUniversity of California, Santa Cruz. She

teaches a range of classes at all universitylevels.Lecture themes: “Seismic, Geodeticand Fluid Flow Constraints onSeismogenic Zone Processes in CostaRica.” “Great Earthquakes and Tsuna-mis: Causes and Effects.”

Joann Stock: Rupturing of

Continental LithosphereTectonics and plate motions are Joann

Stock’s major research interests. Her stud-ies on the Pacific/North America plateboundary in the Gulf of California haveinvolved on-land studies on both sides ofthe gulf, and marine geophysical studiesof the gulf basins. Examples include de-tailed field mapping, volcanic stratigraphy,Ar geochronology, paleomagnetic mea-surements on the rocks deformed duringrifting, and use of geophysical surveys ofselected oceanic areas to constrain the his-tory of Pacific/North American plate mo-tion.

Joann joined the faculty at the Califor-nia Institute of Technology in 1992 and isan adjunct Professor at CICESE inEnsenada, Baja California, Mexico.Lecture themes: “Defining the conti-nent/ocean boundary: Insights from ac-tive rifts.” “Plate tectonics and how con-tinents split apart.”

Interested in hosting a speaker?

Any college or university wishing to invite a MARGINS speaker may apply via the MARGINS Office website:www.margins.wustl.edu/DLProgram/. Applications are due by November 1, 2005 for visiting speakers in Winter-Spring 2006.Invitations from institutions not currently involved with MARGINS research are strongly encouraged, including those grantingundergraduate or masters degrees, as well as those with Ph.D. programs. Institutions may request a technical and/or public lecture.

The MARGINS Office will cover airfares for speakers’ travel and coordinate travel and off-site logistics. Host institutions areresponsible for local living costs for the duration of the visit.

The MARGINS Speakers and Lecture Themes

The MARGINS Office announces the first annual MARGINSDistinguished Lectureship Program for academic year 2005-2006 with an outstanding line-up of speakers.

Distinguished scientists involved with MARGINS science andplanning are available to visit American colleges and universitiesto present technical talks and public lectures on subjects related tothe four MARGINS science initiatives: The Seismogenic Zone;Sedimentation from Source to Sink; the Subduction Factory; andRifting of Continental Lithosphere.

MARGINS Lectures


MARGINS Event Response: Anatahan VolcanoTobias P. Fischer1, David R. Hilton2 and Randall A. White3

1Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque; 2Geosciences Research Division, Scripps Institution of Oceanography; 3U.S.Geological Survey, Menlo Park, California

In May 2003, participants on a MAR-GINS research cruise coincidentally en-countered the first historic eruption ofAnatahan, the southern-most subaerialvolcano of the Mariana island arc.

In response to this unique event, the[Lamont] MARGINS Office organizedthe immediate dispatch of a team of vol-canologists to sample the products of theongoing eruption. Samples collected dur-ing the expedition were distributed to theMARGINS scientific community foranalysis. As a result, MARGINS scien-tists contributed to a Special Session onthe Anatahan eruption at the Fall 2003AGU meeting, and a special issue ofJournal of Volcanology and GeothermalResearch (JVGR) on the eruption co-ed-ited by representatives of the three mainorganizations working on Anatahan: Dr.David Hilton, MARGINS; Dr. JohnPallister, USGS and Rudi Pua, EMO.

Active seismicity and dome buildinghas continued since 2003, and from Aprilto July 2004 Anatahan erupted for a sec-ond time. The third historical eruptionbegan on January 5, 2005. Within twodays, ash was rising to 10,000 feet andblowing 40 nautical miles downwind,and observers were witnessing bombs ameter across being ejected hundreds ofmeters above the crater walls.

According to an EMO report distrib-uted in February 2005, “By January 20explosions were occurring every 3 to 10seconds and fresh ejecta and small lavaflows had filled the innermost crater tonearly the level of the pre-2003 East Cra-ter floor. The eruption peaked duringJanuary 26 and February 2, during whichtime the volcano sent ash as high as15,000 to 20,000 feet locally and as faras 100 miles downwind, and vog nearly

600 miles downwind. Two weeks laterthe 2003 crater floor had essentially beenentirely covered by fresh lava to a diam-eter of about one kilometer.”

Event Response(March 2005)

In order to investigate these new devel-opments, Dr. Tobias Fischer of the Uni-versity of New Mexico, Albuquerque, pe-titioned MARGINS to fund a secondAnatahan event response. NSF approvedthe response via a small supplement tothe MARGINS Office grant, allowing Dr.Fischer and Dr. David Hilton (Scripps)to travel to Anatahan in order to collectrock samples from the 2005 eruption,measure SO

2 flux from the volcano, and

help EMO and USGS with servicing ofseismic stations.

Drs. Fischer and Hilton, accompaniedby Juan T Camacho (EMO) and MikeCunningham (Americopters), arrived atAnatahan by helicopter on the morningof March 14, 2005. While there, theysampled a 3mm layer of ash depositedby the January 2005 eruption on thevolcano’s southeast flank in the vicinityof Frank Truesdell’s section named FTM-03-21 (Truesdell et al., JVGR Anatahanspecial issue, in press). The fresh depositwas scoria poor and contained rare lithics.Inside the main crater, they sampledscoriacious material in the vicinity ofbomb impact craters and bomb frag-ments. From a 15mm covering on the box

Anatahan’s East Crater looking from the west. The crater rim is in the foreground. The EastCrater is nearly filled with lava flows or dome material. Photograph: David Hilton, March14, 2005

Account compiled in part by Paul Wyer, MARGINS Office Coordinator, based on:• T. Fischer and D. Hilton (2005), NSF-MARGINS Expedition to Anatahan Volcano March 2005, www.margins.wustl.edu/Research/AnatahanReport2005.html• R. A. White (2005), Summary of the 5 April 2005 Anatahan Eruption to 50,000 ft., www.margins.wustl.edu/Research/AnatahanReport_3_7_2005.html

Event Response


containing the East Meadow USGS seis-mic station – which they cleaned and re-turned to functionality — they collectedscoria poor ash. Sites on the northeast partof the main crater and the abandoned vil-lage buried in the May 2003 eruption hadno deposits from the 2005 eruption.

Mini-DOAS (differential optical ad-sorption spectrometry) SO

2 flux measure-

ments were obtained by traversing overthe ocean beneath the plume on March14 and March 16. The plume appearedlarger on the 16th than the 14th, and con-tained a significantly higher average SO

2

concentration (340 ppm m versus 130ppm m). Based on the measured windspeeds on East Meadow (3.0 m/s vs. 2.5m/s) and width of the plume at the timeand location of the measurement (~3.2km vs. ~10 km), the SO

2 flux was ~800

metric tons per day on the 16th and ~1000metric tons per day on the 14th respec-tively. On the basis of these preliminaryresults, the SO

2 flux was about half that

of the May 2003 event. However, a de-tailed evaluation of all traverses under theplume will be performed to validate theresults.

Fischer and Hilton also made use ofthe helicopter transfers to, from, andaround the island to observe changes inthe volcano morphology since April2004. The previously deep East Craterarea was now filled with a dome or lavaflow. Vigorously discharging fumarolesand abundant sulfur deposits cover thesurface of the dome. The site of the aban-doned village is now grown over by veg-etation.

Sample Distribution

Samples collected during the March2005 Anatahan event response will be

distributed to the MARGINS communityfor analysis:• Scoria poor southeast flank sample,

Anat 05-01: N16020.057'’;E145039.729’; 49 m.

• Main crater scoracious sample, Anat05-02: N16020.409’; E145041.748’;433 m.

• Scoria poor East Meadow sample,Anat 05-03: N16o20.573’;E145043.028’; 82 m.

Contact Tobias Fischer, [email protected].

Eruption to 50,000 Ft.(April 2005)

Around the time of the MARGINS eventresponse (March 14) the seismicity anderuption of Anatahan started ramping upagain. Activity from that date on wasmarked by periods of seismic quiescence(March 17–21 and March 25–28) and ex-plosive activity (March 21–25 and March28–April 5, peaking on April 3). Eachphase of explosive activity probably cor-responded to reopening of the volcanovent. However, the decline in seismicactivity from April 3 to April 5 was fol-lowed by a slow increase in tremor am-plitudes starting at about 1000 UT on themorning of April 5. There were no pre-cursory seismic signals, but at around1600UT the Guam MeteorologicalWeather Office observed ash rising toaround 30,000 ft. on their radar, whichJennifer Piatt at the Air Force WeatherAgency verified with satellite imagery.Shortly after 1700 UT the Air ForceWeather Agency advised that the ash hadreached 50,000 ft.

The peak of the eruption lasted littleover an hour, but John Ewert of the USGSlater estimated that ~50,000 m3 of ashwas erupted during this interval. This

equates to a large VEI 3. Over anotherhour, the eruption dropped off rapidly tonear background level, at which it largelyremained. On the basis of observationsand computer models, Randall White andJohn Ewert of the USGS were able toadvise the EMO Director that Saipanwould receive only a light (< 2 mm) dust-ing of ash.

The late March-early April eruptiondisabled two seismometers and two mi-crophones on Anatahan island, and leftthe remaining short-period seismometer,ANA2, only partially operational. Fre-quent transmission dropouts owing to ashobscuring transmission paths and solarpanels led to a few false alarms but AndyLockart (USGS) has modified the alarmsystem triggering mechanism to copewith the new circumstances. Lockhartarrived in Saipan on May 10 to attemptrepairs to the seismic and acoustic sta-tions on Anatahan.

References:de Moor, J.M., Fischer, T.P., Hilton, D.R., E.

Hauri , L.A. Jaffe, Camacho, J.T. (inpress) Degassing at Anatahan volcanoduring the May 2003 eruption: Implica-tions from petrology, ash leachates, andSO

2 emissions. J.Volcanol.Geotherm.

Res.Fischer , T.P., Hilton, D.R., de Moor, J.M.F.,

Jaffe, L.A., Spilde, M.N., Counce, D., andCamacho, J.T., 2003. The first historicaleruption of Anatahan volcano, Marianaislands. Eos Trans. AGU 84, (46), V32B-1009.

Truesdell, F.A., Moore, R.E., Sako, M.,White, R.A., Koyanagi, S.K., Chong, R.,Camacho, J.T. (in press) The 2003 erup-tion of Anatahan volcano, Common-wealth of the Northern Mariana Islands:chronology, volcanology, and deforma-tion. J. Volcanol. Geotherm. Res.

Not Receiving MARGINS E-mail?If your address has changed within the last six months, and you haven’t updated your contact

information on file with MARGINS, please do so now at:

www.margins.wustl.edu/MailingUpdateForm.html


Summary of an RCL-related Special Session from the IVth National

Mexican Earth Sciences MeetingCentennial Meeting of the Mexican Geological Society, November, 2004

Joann Stock1, Arturo Martín-Barajas and Juan Garcia Abdeslem2

1California Institute of Technology. 2Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE)

A Special Session related to the MARGINS Rupturing Continental Lithosphere (RCL) Initiative took place Monday, Nov. 1,2004 at the 4th National Mexican Earth Sciences meeting in Juriquilla, Querétaro. This five-day conference celebrated the Cen-tennial anniversary of the Mexican Geological Society. There were over 740 abstracts presented, and more than 1000 attendees.

The topic of the special session was theGeology and Geophysics of the Exten-sional Province of the Gulf of Califor-nia. The session was convened by ArturoMartín-Barajas (CICESE), Juan GarcíaAbdeslem (CICESE) and Joann Stock(Caltech). The session contained 10 oralpresentations and 3 poster presentationsin the morning (www.margins.wustl.edu/meetings/SE14.pdf), followed by a 90-minute discussion session in the after-noon. The oral presentations, by Mexi-can, U.S., and French investigators, fo-cused on new results from studies of theregion. Thus, we heard about the latestresults on lithospheric structure from on-land seismic stations (Xyoli Perez-Cam-pos of UNAM discussing receiver func-tion results from the NARS-Baja seismicnetwork) and from marine studies. LuisRobles, Fiona Sutherland, and HillaryBrown each presented analyses of litho-spheric structure along different marine/onland seismic profiles collected duringthe Ewing 2002 Gulf of California ex-periment. Manuel Aragon used PEMEXmarine MCS data to document a previ-ously unrecognized, now abandoned,early basin system in the northern Gulf.Francois Michaud discussed newmultibeam data collected west of the Pen-insula, over the fossil ridge between thePacific plate and the Farallonmicroplates, which add important con-straints on the plate kinematics during thefinal stages of Pacific-microplate spread-ing. Peter Lonsdale discussed the char-acteristics of seafloor spreading as onegoes from south to north in the Gulf ofCalifornia. Enrique Nava described sedi-mentological characteristics of the riftbased on marine studies near the south-

ern part of the Peninsula. Martin Pachecopresented an updated synthesis of theevolution of the Altar Basin of Sonora.Joann Stock gave a comparison of threesmall rift systems including the Gulf ofCalifornia to examine the similarities anddifferences among them. The poster pre-sentations included seismic ruptureanalysis for seven large earthquakes inthe southern Gulf, presented by AngelicaMartinez; Olga Sarychikhina showed asubsidence analysis in the Cerro Prietoarea where subsidence is largely inducedby steam and water extraction in theMexicali Valley; and finally CarlosPallares presented data on synrift adakiticand high-magnesian rocks in Isla SanEsteban and their possible link to a sub-ducted slab.

Attendance at the oral session variedbetween 20 and 80 people, at times ex-ceeding the 50-seat capacity of the room.The afternoon discussion comprised 10–20 people at any one time, includingmany authors of the morning presenta-tions and others who were interested inthe general discussion. The discussionwas moderated by Martín-Barajas andStock, starting off with an overview ofthe MARGINS RCL Initiative and gen-eral concepts of structural evolution ofthe Gulf of California. We then proceededto explore different perspectives in themorning talks. This included the natureof the symmetry or asymmetry of theGulf of California; whether the seismicestimates for the continent-ocean bound-ary in the Gulf agreed with the morpho-logical estimates of crustal thickness inthe same region, determined by two dif-ferent research groups using differenttechniques. This was followed by a gen-

Sessions and Workshops

eral discussion of the plate tectonic his-tory, including the issue of the timing ofcessation of subduction, and how thechanging slab configuration at that timewould have affected the subsequent geo-logical and petrological development ofNW Mexico.

Although not all MARGINS-fundedRCL Gulf of California investigatorswere able to attend this meeting, it wasclear from the participation that signifi-cant advances are being made in numer-ous areas of importance to theMARGINS RCL Initiative at this FocusSite (i.e., lithospheric structure, conti-nent-ocean transition, geological and tec-tonic history). Many of these projects arebeing supported by non-MARGINS andnon-U.S. funding sources, so that theMARGINS RCL Initiative is benefitinggreatly from the international interest inthis Focus Site. In addition, there wasmention of some upcoming projects, suchas one to study in more detail the petro-genesis of the late Miocene to Recentvolcanic rocks (both marine and on-land).A more comprehensive review of all ofthe advances related to the Gulf of Cali-fornia-Salton Trough MARGINS RCLFocus Site is planned to take place inearly 2006 at a workshop to be held inEnsenada, Baja California.

The abstract volume for the 4th NationalMexican Earth Sciences meeting was pub-lished by the Sociedad GeológicaMexicana. It will be reprinted in GEOS<www.ugm.org.mx/geos2004.html>, v. 24,no. 2, 2004. The abstracts submitted to thespecial session are available online:www.margins .wust l .edu/meet ings/SE14.pdf.


Conveners: Robert Stern, University ofTexas at Dallas and Yoshiyuki Tatsumiand Kiyoshi Suyehiro, JAMSTEC,Japan.

Chair: Julie Morris, MARGINS Chair,University of Washington in St. Louis,USA.

On the evening of December 14, 2005,from 8-11:30 p.m., around 75 scientistsgathered for a mini-workshop on Scien-tific Drilling in the MARGINS Izu-Bonin-Mariana (IBM) Focus Area spon-sored by MARGINS and the Institute ForResearch on Earth Evolution (IFREE) atthe Japan Agency for Marine-Earth Sci-ence and Technology (JAMSTEC). Thelocation was the Grand Hyatt Hotel, SanFrancisco, CA, providing an open-dooropportunity for attendees of the preced-ing IODP Town Meeting next door toparticipate. In convening the mini-work-shop, MARGINS and IFREE expectedto stimulate international communicationand broaden scientific collaboration inproposal development, strengtheningexisting proposals and leading to the de-velopment of new proposals for IODPdrilling in the IBM convergent marginsystem.

Julie Morris opened the workshopwith an overview of the objectives of theMARGINS Subduction Factory Initiativein the Izu-Bonin-Mariana Focus Area.The initiative aims to improve our un-derstanding of the processes controllingchemical, mass and energy fluxesthrough subduction zones. This goal re-quires integration of constraints fromobservable features (geophysics,geochemistry and field observations) al-lied with experimental studies and uni-fied process modeling. Deep drilling iscritical in expanding our knowledge ofin situ subduction zone geochemistry andstructural relationships.

Kiyoshi Suyehiro of JAMSTEC pre-sented possible applications of the Japa-nese IODP vessel, Chikyu, in the IBMFocus Area and around the world. Pro-

posals to use Chikyu’s riser drilling ca-pabilities had, as yet, been limited, de-spite the potential to hit deeper targetsthan previously possible. With carefulplanning, and exceptional pre-surveyingof formations to drill through, it shouldbe possible to drill the Moho given shal-low water depth and thin crust to pen-etrate. However, to do so would requirearound four years of preparatory survey-ing, including deep and shallow seismicsurveys, side-scan sonar, core samples,etc., and repeated reoccupation of thehole across several seasons. The manytechnical challenges would be significant,but such an experiment could yield anentire crustal section, with abundant re-search potential in every depth range. Forless technical targets, the Chikyu couldexpect to drill one to two deep holes peryear.

Kiyoshi was followed by YoshiyukiTatsumi of JAMSTEC, who introduceda series of proponents with IODP pro-posals in the system. Patty Fryer (pro-posals 505, 506 and 648), YoshihikoTamura (proposal 614), and Jon Snow(proposal 640) each presented the statusof the pending IODP proposals in whichthey have been involved. The speakerscaptured the breadth of scientific prob-lems that might be addressed throughdeep drilling in the IBM Focus Area.

Proposals 505 and 506 would useriser- and riserless- drilling of serpentiniteseamounts associated with shallow sub-duction to investigate the chemical his-tory of the subduction zone, perhaps tothe onset of subduction. Associated workusing sensor arrays of multiple typeswould hope to “capture a subductionevent” at one of several probable sites.

Proposal 614 would contribute to un-derstanding of IBM’s 3-D evolution byinvestigating transient events and forma-tion of continental crust through drillingof Quaternary back-arc seamount volca-noes. Placing the proposed drilling sitesin the back-arc would allow investiga-

tion of “hot fingers” rising through themantle wedge without continental con-tamination.

Proposal 640 would drill a “megamullion,” which are striated structuresconsisting of mantle and lower crust ex-humed within the back-arc duringamagmatic extension.

Tatsumi stressed that the SubductionFactory community would need topresent convincing answers to why deepdrilling is needed in IBM and encouragedthe community to prepare a CDP (Com-plex Drilling Project: a multi-vessel andmulti-expedition project) proposal thataims to comprehensively understand therole of subduction factory in evolutionof the Earth system. Discussion alsopointed out that proposals would need toemphasize the global fundamental impor-tance of science questions to be addressedat Izu-Bonin-Mariana.

Robert Stern, University of Texas atDallas, noted what an incredible tool theIODP drilling ship Chikyu is, and rhetori-cally asked why there had been only 5proposals submitted to make use of itscapabilities in the IBM Focus Area. Hepresented some “conversation starters,”including tie-ins with the deep biosphere(if life is ultimately limited by high tem-perature, then the deepest biosphere mustbe found in cold subduction zones andforearcs) and opened the floor for discus-sion

The discussion that followed waslively and productive, continuing wellbeyond the planned 10 p.m. finishingtime. Most attendees remained until dis-cussion wrapped up at around 11:30 p.m.Much time was spent debating whetherdrilling to the Moho could be justified inthe light of the large time and financialcost involved in a project that would takemore than a year and multiple re-occu-pations of the hole to complete.Anotherchallenge relates to the maximum depthfor riser drilling of 2500 m below sea

MARGINS-IFREE Mini-Workshop at AGU 2004Scientific Drilling in the MARGINS Izu-Bonin-Mariana Focus Area

“MARGINS-IFREE” cont. on page 30


Results of the MARGINS Student Prize Competition — AGU 2004Results of the MARGINS Student Prize Competition — AGU 2004Results of the MARGINS Student Prize Competition — AGU 2004Results of the MARGINS Student Prize Competition — AGU 2004Results of the MARGINS Student Prize Competition — AGU 2004

Congratulations to all those that entered our second annual student competition, which took place at the AGU 2004 Fall Meeting. Asin 2003, the judges of the 2004 competition were greatly impressed by the quality and diversity of all 49 entries (nearly twice as manyas last year). We recognize here the outstanding entries that received the highest scores by our judges.

The MARGINS Prize accepted entries from students in any nation who could establish a link between their research and astated aim of a MARGINS Program Initiative. The winner and honorable mentions reflect the diversity of the field, with a near-even gender split (5 female, 3 male), representation across the four MARGINS Initiatives, and several countries represented.

Our thanks go to the Judges and to the students who entered. Together, it is their efforts that make the MARGINS StudentPrize possible. We are also grateful to AGU for their cooperation and assistance with logistics both before and during themeeting.

Winner:

Ian Bastow, Uni-versity of Leeds,UKStudent’s Comment:“It is a great honour tobe recognised by the

NSF MARGINS - I thank you for thisaward. It has also been a pleasure to workwith the marvellous EAGLE workinggroup over the past three years. Withouttheir input and the successful collaborationof all the GB/US/Ethiopian groups in-volved with the project, this presentationwould have never been possible.”

From the Judges:Judges remarked on how Ian’s “excellent”presentation balanced expectations,observations and data with clear coverageof assumptions and error bounds.

Title of Abstract:Upper Mantle Seismic Structure of theNorthern Ethiopian Rift - a Region ofIncipient Continental Breakup

Co-Authors:G.W. Stuart, J-M. Kendall, C.J. Ebinger,and A. Ayele

Honorable Mentions:

Megan Anderson,University ofArizonaStudent’s Comment:“Thanks for thehonorable mention!

I’m excited that my research has signifi-cance for the scientists involved in theMARGINS program and the tectonicquestions supported by their research

initiatives.”

From the Judges:Careful attention to the knowledge andunderstanding of her audience helpedMegan effectively convey her research tothe MARGINS judges.

Title of Abstract:Multiple Layers of Anisotropy in the Chile-Argentina Subduction Zone, South America

Co-Author:George Zandt

Laura Baker,California Instituteof TechnologyStudent’s Comment:“I am honored andinspired to have my

research recognized by MARGINS.”

From the Judges:“Well done!” Laura scored well across theboard, and did a great job of answeringquestions at the end of her presentation.

Title of Abstract:Subduction Dynamics and Mass Transfer:A Synthesis Model

Co-Authors:Chad Hall, Paul Asimow, Paula Smith,Michael Gurnis

Louise Bolge,Rutgers UniversityStudent’s Comment:“Thank you to theMARGINS Programfor this recognition.

This was my first talk at AGU, and I amvery excited that it was so well received.It’s always reassuring to know others areinterested in your research. Thank you.”

From the Judges:The clarity of Louise’s talk, “even for anon-specialist,” and good handling ofquestions, impressed the judges.

Title of Abstract:The Geochemical and Petrological Historyof Arenal Volcano, Costa Rica

Co-Authors:Michael J Carr, Mark D Feigenson,Guillermo E Alvarado

Kyla Simons,Lamont-DohertyEarth ObservatoryStudent’s Comment:“I am honored andgrateful to receive this

recognition. It is inspiring to be acknowl-edged for your effort and contribution tothe understanding of margins, and I hopethat the MARGINS Prize further encour-ages students to conduct margins relatedresearch.”

From the Judges:For one MARGINS judge this was the bestentry he’d seen. Kyla scored well in allareas.

Title of Abstract:Lithium Isotopic Composition of Guatema-lan Jadeitites

Co-Authors:Charles Langmuir and George Harlow

Jennifer Wade,Boston UniversityStudent’s Com-ment:“Thank you forhonoring our work in

Costa Rica! It’s very encouraging, as astudent, to be recognized by such a great

Spotlight on Education

MARGINS SpotliMARGINS SpotliMARGINS Spotlight on Education and Outrght on Education and Outrght on Education and Outreaceaceachhh


In this edition’s Spotlight on Educationand Outreach, we feature a MARGINS-funded scientist who has participated inexceptional education and outreach ac-tivities.

Dr. David Hilton, Scripps Institutionof Oceanography, UCSD, is a self-con-fessed “fieldwork junkie.” He even methis wife while visiting volcanoes in In-donesia. Fortunately, fieldwork is a pas-sion that he and his colleagues are happyto share. Together, they have documentedfieldtrips to the MARGINS CentralAmerica and Izu-Bonin-Mariana FocusSites online, creating real-time “web-ex-peditions” that combine background in-formation with daily updates on theirfield activities through images, videosand reports:• http://sio.ucsd.edu/volcano/• http://sio.ucsd.edu/marianas/

The MARGINS Office caught up withDavid shortly before his recent MAR-GINS event response to Anatahan in theIzu-Bonin-Mariana Arc (see p. 12), andasked him how he and his collaboratorscame to run online web expeditions docu-menting their field studies in CentralAmerica and the Mariana Islands, andwhat plans he has for future outreach.

David Hilton, Sept. 2005. In the background isGuguan Island in the Marianas,

Virtual Field Trips: An Interview with David HiltonVirtual Field Trips: An Interview with David HiltonVirtual Field Trips: An Interview with David HiltonVirtual Field Trips: An Interview with David HiltonVirtual Field Trips: An Interview with David HiltonPaul Wyer, MARGINS Office Coordinator

scientific community.”

From the Judges:Jennifer scored very highly on the organi-zation and clarity of her presentation.

Title of Abstract:High Water Contents in Basaltic MeltIinclusions from Arenal Volcano, CostaRicaCo-Authors:T. Plank, E.H. Hauri, W. Melson, and G.J.Soto

Girma Woldetinsae,Christian AlbrechtsUniversity Zu KielStudent’s Comment:“I am really happy andthe recognition encour-

ages me to update and continue my re-

search.”

From the Judges:“Fabulous!” was one MARGINS judge’scomment on a poster that attracted lots ofinterest from other delegates as well.

Title of Abstract:The lithosphere of the East African Riftsystem (Ethiopia-North Kenya): Insightsfrom three-dimensional density modelling

Co-Author:H.-J, Götze

Matthew Wolinsky,Duke UniversityStudent’s Comment:“I am excited andgrateful to be recog-nized by MARGINS,

and I look forward to many fruitful discus-

sions with members in the future. MAR-GINS enables scientific dialog acrosssubfields, which enriches my research andfacilitates the development of betterinformed research questions and collabora-tions.”

From the Judges:The MARGINS judges remarked onMatthew’s noteworthy enthusiasm for hisresearch and command of the subject.

Title of Abstract:Coupled Passive Margin StratigraphicEvolution and Fluid Flow

Co-Author:Pratson, L.F.

The idea for the first web expeditioncame about when the Scripps magazine“Explorations” was planning to do an ar-ticle on David’s work on volcanoes. Athis suggestion it was agreed that themagazine would send somebody alongon an expedition to Costa Rica, and fromthis he came up with the idea of an onlineweb expedition. With only a limited num-ber of people on any expedition, itseemed like an ideal way of “sharing theexcitement [of] visiting interesting andbeautiful parts of the world, liaising with

scientists with completely different back-grounds [and] meeting the local inhabit-ants.

“Once Scripps agreed to the originalidea - and to pay for a science writer(Joe Hlebica) and web master (WayneSuiter) to join us on the expedition - theidea took off. We did much of the workbefore the expedition even started andthat involved a lot of time designing webpages and writing background text. Itactually helped with the planning of thefieldwork.”

David sees the background work as akey element of a web expedition. He andhis colleagues wanted their audience tounderstand what the important sciencequestions to be answered were, and whatcould be gained through field research.Perhaps surprisingly, very little specialequipment was needed for the web ex-peditions. The only significant purchaseswere a digital camera, a video camera,and video editing and compression soft-ware. In total, the expense was around$2000, and members of the group ben-efited from learning how to use the equip-ment and technology. “I didn’t think it

see “Hilton” continued on page 30


The Seismogenic Zone of Subduction Thrust Faults

MARGINS Theoretical and Experimental Earth Science Series, Volume 2

Columbia University Press, 2006.

Table of Contents

• Timothy H. Dixon and J. Casey Moore, The SeismogenicZone of Subduction Thrust Faults: Introduction

• Roy D. Hyndman, The Seismogenic Zone of SubductionThrust Faults: What We Know and What We Don’t Know

The Incoming Plate

• Michael B. Underwood, Sediment Inputs to SubductionZones: Why Lithostratigraphy and Clay Mineralogy Matter

• M. Hutnak, A. T. Fisher, C. A. Stein R. Harris, K. Wang, E.Silver, G. Spinelli M. Pfender, H. Villinger, R. Macknight, P.Costa Pisani, H. DeShon, and C. Diamente, The ThermalState of 18-24 Ma Upper Lithosphere Subducting Below theNicoya Peninsula, Northern Costa Rica Margin

• Susan L. Bilek, Influence of Subducting Topography onEarthquake Rupture

Convergent Margin Structure, Fluids and

Subduction Thrust Evolution

• Barbara A. Bekins and Elizabeth J. Screaton, Pore Pressureand Fluid Flow in the Northern Barbados AccretionaryComplex: a Synthesis

• Demian Saffer, Pore Pressure Within Underthrust Sedimentsin Subduction Zones

• Julia K. Morgan, Elizabeth B. Sunderland, and Maria V. S.Ask, Deformation and Diagenesis at the Nankai SubductionZone: Implications for Sediment Mechanics, DecollementInitiation and Propagation

• Kirk D. Mcintosh, Eli A. Silver, Imtiaz Ahmed, ArnimBerhorst, Cesar R. Ranero, Robyn K. Kelly, and Ernst R.Flueh, The Nicaragua Convergent Margin: Seismic Reflec-tion Imaging of the Source of a Tsunami Earthquake

• J. Casey Moore, Christie Rowe, and Francesca Meneghini,How Accretionary Prisms Elucidate Seismogenesis inSubduction Zones

Laboratory Studies

• Chris Marone and Demian Saffer, Fault Friction and theUpper Transition From Seismic to Aseismic Faulting

• N.M. Beeler, Laboratory-observed Faulting in Intrinsicallyand Apparently Weak Materials: Strength, Seismic Coupling,Dilatancy and Pore Fluid Pressure

• Diane E. Moore and David A. Lockner, Friction of theSmectite Clay Montmorillonite: a Review and Interpretationof Data

Seismic and Geodetic Studies

• Akira Hasegawa, Naoki Uchida, Toshihiro Igarashi, ToruMatsuzawa, Tomomi Okada, Satoshi Miura, and Yoko Suwa,Asperities and Quasi-static Slip on the Subducting PlateBoundary East off Tohoko, Northeast Japan

• Thorne Lay and Susan Bilek, Anomalous EarthquakeRuptures at Shallow Depths on Subduction ZoneMegathrusts

• Kosuke Heki, Secular, Transient and Seasonal CrustalMovements in Japan From a Dense GPS Array: Implicationfor Plate Dynamics in Convergent Boundaries

• Kelin Wang, Elastic and Viscoelastic Models of CrustalDeformation in Subduction Earthquake Cycles

• Susan Y. Schwartz and Heather R. DeShon, Distinct Up-dipLimits to Geodetic Locking and Microseismicity at theNorthern Costa Rica Seismogenic Zone: Evidence for TwoMechanical Transitions.

Regional Scale Deformation

• Tetsuzo Seno, Collision Versus Subduction: the Importanceof Slab Dehydration

• Jonas Kley and Tim Vietor, Subduction and MountainBuilding in the Central Andes.

• Inside the Subduction Factory www.agu.org/cgi-bin/agubookstore?book=SEGM1389973&search=subduction%20factory

• Rheology and Deformation of the Lithosphere at Continental Margins www.columbia.edu/cu/cup/catalog/data/023112/0231127383.HTM

Additional MARGINS Volumes Currently AvailableOrder through the web addresses given, or additional information may be found at www.margins.wustl.edu/Books.html


MARGINS Steering Committee Highlights, Spring 2005

Steering Committee

The MARGINS Steering Committee(MSC) met with NSF Program Officersand visitors April 11–12, 2005, at NSFHeadquarters, Arlington, VA.1. Dr. Julie Morris, MARGINS Chair

welcomed new MSC members MikeBlum (Louisiana State University),Roger Buck (Lamont-Doherty EarthObservatory, Columbia University)and Elizabeth Screaton (University ofFlorida).

2. H. Lawrence Clark, Acting DivisionDirector of Ocean Sciences at NSF,briefed the MSC on OCE matters:• Candidate suggestions for the

vacant OCE Division Directorposition had been sought from thecommunity.

• Government funding for NSF isexpected to be flat for the foresee-able future; cruise timelines mightbe affected, and OCE could decideto become more specific in theterms of proposal solicitations.

• OCE plans and commitments for thenext decade would include replace-ment of the IODP drill ship JOIDESResolution, three new researchvessels, and an HOV to replaceALVIN.

• A specialist position within OCE isplanned for management of environ-mental impact issues.

3. Bilal Haq, NSF-MG&G, gave hisProgram Manager’s report on MAR-GINS and MARGINS funding:• Contributions from MG&G, ODP,

and EAR to MARGINS funding for2005 are expected to drop by ~15–25% relative to the $6.15M total2004 budget. Existing awardcommitments would leave ~$2.8Mavailable for new awards.

• Haq assured the MSC that awarddecisions are made on the basis ofbest science, with no reference tothe contributions from each fundingsource (EAR, MG& G, and IODP)within NSF.

• The new MARGINS deadline willmake it easier for NSF to redirectproposals to MARGINS or corepanels as appropriate.

• The standard of proposals submittedfor MARGINS support remainshigh in all Initiatives.

• The community is set to submit aproposal for the Community SurfaceDynamics Modeling System, whichevolved from planning of theCommunity Sediment Model. Iffunded the proposal will involveNSF, Office of Naval Research(ONR) and USGS support, andmight be phased in to mitigateexpense.

• The MARGINS Chair will, as in2004, present the 2005 MARGINSpanel with an overview of the statusof each Initiative with directreference to the Science Plan. TheMSC and Chair will not see theproposals or be involved in theprocess in any other way.

4. Revisions to the MARGINSPostdoctoral Fellowship announce-ment were considered by NSF and theMSC. The document will be releasedonce changes have been made andapproved.

5. Dr. Gregory van der Vink, EarthscopeProject Director, was a guest at themeeting. After briefing the MSC onEarthscope’s timeline and plans he leddiscussion of potential collaborationswith MARGINS (see p. 22):• Earliest stages of the Earthscope

USARRAY transportable seismicarray will provide terrestrial moni-toring of the Cascadia subductionzone and southern California at ~70km spacing. The transportable arraywill be supported by dense arrays offlexible and fixed seismometers,GPS receivers and magnetotelluricsensors.

• The southern California stationswill be well situated to monitorseismic activity in the SaltonTrough and northern Gulf ofCalifornia, as are the many perma-nent seismic stations in the region.

• USARRAY deployments of 18–24months are one-time only.Earthscope is keen to help maximizethe return across programs anddisciplines.

6. MSC member Rudy Slingerland

briefed the MSC on the proposedCommunity Surface DynamicsModeling System (CSDMS), withDr. Tom Drake, Coastal GeosciencesProgram Manager at ONR, attendingas a guest of the MSC:• ONR is particularly interested in

S2S system transitions, such asintegration between nearshore andonshore processes. For this reasonthey are interested in co-funding theCSDMS.

• The MSC affirmed that a CSDMSwould be valuable in advancing S2SScience Plan goals, much as theComputational Infrastructure forGeodynamics (CIG) benefits theother initiatives.

• The MSC felt it would be advanta-geous for the MARGINS DataManagement System group to berepresented at CSDMS meetings.Advantages might include use ofS2S focus sites and/or data as test-beds for the CSDMS and enhancedS2S community involvement inMARGINS Data Management.

7. Dr. Richard Jahnke visited the MSC onbehalf of the Ocean Research Interac-tive Observatory Networks (ORION)Executive Steering Committee, to talkabout ORION and the Ocean Observa-tories Initiative (OOI).• Although the OOI plans are well

advanced, opportunities remain forMARGINS research to benefitthrough technological transfers,international observatory efforts,testing of hypotheses, and investiga-tion of critical processes at MAR-GINS Focus Sites.

• The MSC would consider ways toraise the profile of MARGINS withrespect to OOI, and encouragerepresentation of mutually advanta-geous objectives at OOI planningworkshops.

8. MSC Initiative subgroups briefed therest of the MSC on scientific progressin each Initiative.

9. MSC member Mark Reagan reviewedthe March 2005 Anatahan eventresponse (see p. 12).

10. Harold Tobin, Earth and Environmen-tal Science Department, New Mexico


Tech, briefed the MSC on IODP“Complex Drilling Project” proposalsfor the Nankai seismogenic zoneMARGINS Focus Site.

11. The status of the MARGINS Theoreti-cal and Experimental Earth ScienceSeries published by Columbia Univer-sity Press (CUP) was discussed:• SEIZE 2003 Theoretical Institute

and 2004 Intermargins ExtensionalDeformation of the LithosphereWorkshop volumes are in prepara-tion.

• The MARGINS Office and serieseditors are negotiating a per-bookpartial underwriting with CUP forexpedited publication and use ofcolor without author fees. Otherissues include author reprints,citation and electronic availabilityof papers.

12. As part of MSC-led Education andOutreach efforts, it was agreed that aMARGINS Speaker Series be coordi-nated by the MARGINS Office. See p.11.

13. Drs. Andrew Goodwillie of the MarineGeoscience Data Management System(MgDMS) and Paul Wyer of theMARGINS Office updated the MSCon MARGINS data management

issues:• In January an MSC subgroup met

with MgDMS to discuss manage-ment of non-marine data types.

• As a result of the meeting, MgDMSoverhauled the structure of the DMSto allow more flexible datahandling.

• MgDMS are reworking both marineand non-marine metadata forms foreasier use and greater clarity.

• The MSC will continue to liaisewith the MgDMS group whereappropriate. Annual meetingsbetween the MgDMS group and aspecialized MSC subgroup willfocus on topical MARGINS datamanagement issues.

• Alongside their other activities,MgDMS continue to pursue col-laborative efforts with other US andinternational databases of directrelevance to MARGINS.

• See pp. 8-10 for more informationon MARGINS data management.

14. Workshops:• A MARGINS Office award supple-

ment will fund an RCL-Gulf ofCalifornia Workshop.

• A proposal is being prepared for aSource-to-Sink Theoretical and

Experimental Institute workshop.• A supplement to the MARGINS

Office award may be proposed tofund a MARGINS Education andPublic Outreach workshop in 2006.

• The MSC also considered timelinesfor potential future Initiative, FocusSite, and synthesis workshops.

15. Other matters:• Pat Wiberg rotated off the MSC and

was thanked by Dr. Morris and theMSC for her contributions overseveral years.

• Lincoln Pratson, Duke University,would join the MSC effective theday after the meeting.

• Morris asked the MSC to considernominations for its next Chair, tocommence in late 2006. The Chairmay be a current member of theMSC, a past member rotating backon the MSC in order to serve asChair, or from outside the MSCaltogether.

The next MSC meeting was deferred untilJan/Feb 2006 in order to realign the bi-annual meetings with the new NSFtimeline for MARGINS proposals. Ifnecessary, an MSC teleconference willbe held in Summer/Fall 2005.

-PW

In June, MARGINS Office Administrator Laura Kyro took a position with the Washington University School of Medicine asa publications and web designer. Laura joined us in 2004 when the Office relocated to Washington University in St. Louisand played a major role in establishing the office at its new location and handling the myriad responsibilities that crossed herdesk each day. We at the MARGINS Office will miss her and wish her every success in her new role.

Laura is replaced by Meredith Berwick, a recent graduate of Washington University with anA.B. in environmental studies and German. Meredith’s degree program and experiences in thePathfinder Program in Environmental Sustainability provided her with a solid background inscience policy, writing, and management. The position is ideal for Meredith because, in herown words, “The chance to be involved with a major science program such as MARGINS soearly in my career is an unusual one. This is a great opportunity for me while I consider attend-ing graduate school.” When not saving the environment, Meredith can be found practicing theviolin, playing with her cats, or watching low-budget action movies.

We welcome Meredith to the Office and plan to use her perspective as a recent undergraduatestudent to further our education and outreach efforts.

MARGINS Office UpdateMARGINS Office UpdateMARGINS Office UpdateMARGINS Office UpdateMARGINS Office Update


EGU 2005: Submarine Erosion Special SessionEGU 2005 hosted a large number of sessions and papers of interest to the MARGINS science community. Among theMARGINS-related content was a Special Session on Submarine Erosion convened by Neil C. Mitchell (Cardiff Uni-versity) and Roger Urgeles (University of Barcelona). The seventeen abstracts, from studies around the world, focusedon canyon morphology and its creation by erosion by sedimentary flows and slope instability, as well as attempts toestablish relationships between recognized onland processes and less certain offshore equivalents. The session empha-sized improving techniques for measuring erosion, stratigraphic control and slope stability, as well as for theoreticalmodeling, and their great potential for future advances in quantitative submarine geomorphology. The MARGINSwebsite hosts a more detailed report by the session conveners: www.margins.wustl.edu/Meetings/EGUreport05.html.

The MARGINS Office is well positioned to highlight cutting edge science presented at workshops and special ses-sions of specific interest to the MARGINS community via its website, Newsletter, and mailing list. Such reports maybe submitted via e-mail to [email protected].

During July 11-16, 2004 InterMARGINShosted its first workshop: “Modeling theextensional deformation of the lithos-phere.” The workshop was an enormoussuccess and the international participantswere appreciative for its open, frank, andpositive discussions. The workshop’sambitious objectives were to:1) Summarize the latest developments inextensional basin and lithospheric defor-mation concepts, key results (both obser-vational and modeling), and modelingcodes developed over the last few years.2) Benchmark basin and lithosphericcodes in terms of temperature structure,strain rates, subsidence/uplift patterns inspace and time.3) Identify and generate a set of fun-damental lithospheric extension observa-tions (geological, onshore and marinegeophysical, petrophysical, and petro-logical data) for constraining and testingtheoretical and conceptual models.To capture the spirit and cross-disciplin-ary nature of the various discussions andinteractions, the workshop proceedingswill be published as part of the “MAR-GINS Theoretical and ExperimentalEarth Science Series” series. Publicationis expected towards the end of 2006.Chapters received thus far are:

• COWIE, P.: Spatio-temporal evolution ofstain accumulation during lithosphericextension: Observational constraintson theoretical models for continentalbreakup

• ROBERTSON, A.H.F.: Overview ofprocesses related to rifting andopening of Mesozoic ocean basins inthe Early Tethys: Oman, Himalayasand the Eastern Mediterraneanregions

• DIREEN, N.G. et al.: Nature of thecontinent-ocean transition zone alongthe southern Australian continentalmargin: a comparison of theNaturaliste Plateau, south-westernAustralia, and the central GreatAustralian Bight sector

• MANATSCHAL, G. et al.: Observa-tions from the Alpine Tethys andIberia/Newfoundland margins perti-nent to the interpretation of continen-tal break-up

• HARRY, D.L. AND GRANDELL, S.: Adynamic model of rifting betweenGalicia Bank and Flemish Cap duringopening of the North Atlantic Ocean

• TUCHOLKE, B., et al.: Breakup of theNewfoundland-Iberia rift

• SIBUET J-C, et al.: Lower CretaceousMotion of Flemish Cap with Respectto North America: Implications on theFormation of Orphan Basin and SEFlemish Cap/Galicia Bank conjugate

margins• COCHRAN, J.: Constraints on the

Extensional Deformation and Ruptur-ing of Continental Lithosphere fromthe Red Sea

• RESTON, T.: The formation of the non-volcanic rifted margins by the pro-gressive extension of the lithosphere

• HUISMANS, R.S. and BEAUMONT,C.: Roles of lithospheric strainsoftening and heterogeneity indetermining the geometry of rifts andcontinental margins

• EGAN, S.: A Kinematic ModellingAppreach to lithosphere Deformationand Basin Formation: Application tothe Black Sea and Iberia Margin

• MORESI, L.: Comparison of Methodsfor Very Large Deformation Modelsof Lithospheric Extension and Failure

• HEALY, D. & KUSZNIR, N.: Earlykinematic history of the Goban Spurrifted margin derived from a newmodel of continental breakup and seafloor spreading initiation

• BUROV, E.: The Role of the Gravita-tional Instabilities, the DensityStructure and the Extension Rate inthe Evolution of Slow ContinentalMargins

• DYKSTERHUIS, S.: Initial WeaknessControls on Rift Mode: Implicationsfor the Iberian-Newfoundland Margin

Imaging, Mapping, and Modeling Extensional Processes and SystemsMARGINS Theoretical and Experimental Earth Science Series volume 3

Editors: G. Karner, G. Manatschal and L. Pinheiro

MARGINS Newsletter No. 14, Spring 2005 Related Programs

Earthscopewww.earthscope.org

Earthscope has already started deployinginstruments in Southern California andthe Pacific Northwest, and its Transport-able Array of seismometers will soonbegin its march across the US.

Of particular interest to MARGINSscience are the instrument deployments(USArray seismometers and PlateBoundary Observatory GPS stations andlaser/borehole strainmeters) in Cascadiaand within and around the Salton Trough,which is a northern extension of the Gulfof California. From now through ~2008-2009, both areas will be traversed by theUSArray Transportable Array of 400broadband seismometers at ~70km spac-ing. Western USA GPS stations, “back-bone” seismometers, and strainmeters arebeing deployed across a 2004-2008timeframe.

The combined Earthscope data shouldprovide an immensely useful resource toMARGINS scientists, particularly thosefocused on subduction seismogenesis andcontinental rifting. Existing and poten-tial MARGINS PIs may wish to considerways to maximize the Earthscope oppor-tunity in their studies by applying forappropriate proposal supplements and/orworking some degree of integration intonew proposals. In addition, NSF-EAR areinviting proposals auxiliary to any partof Earthscope, and intend to supportshort-term Flexible Array seismometerand/or campaign GPS deployments tar-geted at specific scientific problems. Seethe Earthscope website for details.

Ocean Research InteractiveObservatory (ORION)www.orionprogram.org

Much advance planning has gone into theOcean Research Interactive Observatory(ORION) Program, envisioned by NSF

as an opportunity to “design, build andoperate a science-driven ocean observa-tory system. . . [that would] allow reso-lution of episodic and long-term phenom-ena that can not normally be detected bytraditional means.”

The scientific nodes of the anticipatedORION/Ocean Observatories Initiative(OOI) Regional Cabled Observatorywould, in conjunction with the joint Ca-nadian-US NEPTUNE project, span~200,000 km2 of the Juan de Fuca andExplorer plates at ~100 km intervals.Among the scientific topics to be ad-dressed are dynamic processes of fluidsand gas hydrates on the continental mar-gin, plate tectonic processes, and earth-quake dynamics of the Cascadiasubduction zone – a Subduction Factoryallied study site. Insights into theCascadia seismogenic zone may also betransferable to the mechanically similarNankai Trough Focus Site. Hence pro-posals for integrative study may be pos-sible in both SubFac and SEIZE. TheCanadian component of NEPTUNE isexpected to become operational in 2008.

Coastal observatories will be set upto provide continuous documentation ofdynamic coastal systems using cabledand mooring based instruments. Al-though only U.S. coastal environmentsare presently being targeted, event dataand the progressive technologies appliedmay be of great interest to Source-to-Sinkscientists.

The Global component of ORION/OOI will place long-term observatoriesat key ocean locations. These locationsare still to be decided, and those with aninterest are encouraged to consider howORION and MARGINS might each ben-efit from long-term observatories in oneor more MARGINS focus sites. Pleasecontact Richard Jahnke at ORION/OOIfor information on forums where yourvoice can be heard.

IODPwww.iodp.org

A significant portion of MARGINS re-search is supported and enacted under theIODP Program. One example is theNanTroSEIZE complex drilling project,which includes eight proposed riser andnon-riser drilling sites, to depths from~500 to ~6000 m below seafloor in theNankai Trough. The fundamental goal is“creation of a distributed observatoryspanning the up-dip limit of seismogenicand tsunamigenic behaviour.” The drill-ing effort is supported by non-IODP geo-physical and seafloor studies, includingdeep- and 3-D- reflection seismic sur-veys. For more information see:www.ees.nmt.edu/NanTroSeize/

InterMARGINSwww.intermargins.org

In 2004 the ongoing relationship betweenMARGINS and InterMARGINS yieldedtangible benefits, as fifteen US scientistsparticipated in the highly successful“InterMARGINS Rupturing of the Con-tinental Lithosphere” (IMEDL) work-shop (MARGINS Newsletter no. 13, Fall2004). IMEDL was the first workshopunder the InterMARGINS banner.

The InterMARGINS Office moved toJAMSTEC, Japan, in the New Year. Weoffer our thanks to Bob Whitmarsh, theoutgoing Chair, for his efforts in estab-lishing InterMARGINS as a working pro-gram, and wish Dr. Wonn Soh and hiscolleagues success in their stewardship.

Ocean Margins LINKwww.nerc.ac.uk/funding/

thematics/oceanmargins/

The Ocean Margins LINK (OML)Programme is co-funded by the UKNatural Environment Research Council

Related ProgramsAs the MARGINS Program continues to mature, its relationship to other major science initiativesbecomes ever more important. This article discusses developments in several related U.S andinternational programs.

see “Related” cont. on page 29


NSF Award 0405654 [2004 Panel]

Collaborative Research: Seismic Mea-surements of Magma Flux, Arc Com-position, and Lower-plateSerpentinization in the Central Ameri-can Subduction FactoryW. S. Holbrook

University of Wyoming

Intellectual Merit: The fundamentalgoal of the Subduction Factory (SubFac)initiative of NSF’s MARGINS programis to determine the inputs, outputs andcontrolling processes of subduction zonesystems. Achieving this goal requires aninterdisciplinary array of studies that willdelineate the geophysical and geochemi-cal characteristics of the entire subduc-tion system, from the downgoing plateto the backarc. In particular, success ofthe MARGINS SubFac initiative will de-pend on improved knowledge of the com-position, thickness, and spatialheterogeneity of volcanic arcs, whichrepresent the accumulated magmatic out-put of the Subduction Factory.

We propose an active-source seismic in-vestigation of the volcanic arc, backarc,and downgoing plate in the Costa Ricanportion of the Central American FocusSite. Detailed knowledge of arc structureconstitutes a major gap in our knowledgeof this Focus Site. Our program focuseson the central Costa Rican segment ofthe arc, the site of important transitionsin lava chemistry, because the narrowisthmus here is well-suited for detailedseismic imaging using onshore-offshoretechniques. This location also enables theincorporation of data from the regionalCosta Rican seismic network with ourproposed areal active-source array. Thiscombination will result in the most de-tailed 3D image of arc crustal structureto date.

Our principal goals are to determine thebasic crustal architecture, composition,

integrated magma flux, and fractionationprocesses of the arc, and to constrain thedegree of hydration (e.g., serpentin-ization) in the downgoing Cocos Platelithosphere. This work will address sev-eral fundamental questions, including: (1)What is the bulk composition of the Cen-tral American arc and, by inference, ofits primary magma? (2) What is the long-term magma flux into the arc, and howdoes it compare to other arcs? (3) Whatare the length scales and degree of lat-eral variability in the Costa Rica arc? (4)Does the state of hydration of oceaniccrust and upper mantle vary along the arc,and if so, does it correlate with changesin the “fluid signal” (e.g., Ba/La) of arclavas? These questions are intimatelyconnected to all three “fundamental sci-ence themes” delineated in the Subduc-tion Factory Science Plan.

Forcing functions in the Costa Rica sub-duction system contrast strongly withthose in the other SubFac focus site, theIzu-Bonin-Mariana system: the CostaRican system is characterized by a sig-nificantly younger lower plate, higherconvergence rates, thicker upper-platecrust, and the absence of a back-arcspreading system. Lavas from theMarianas and Costa Rica show intrigu-ing contrasts in trace-element and major-element chemistry, suggesting linksbetween forcing functions and lavachemistry. Comparison of our results toforthcoming results from the Marianassystem will enable testing of hypothesesregarding the influence of key forcingfunctions on arc magmatic processes.

Broader Impacts: Our study will havebroad impacts on a number of importantfronts, including education, outreach, in-ternational collaboration, and enhancingscientific infrastructure in a developingcountry. This study directly serves NSF’sgoals of integrating research and educa-tion, and of training future scientists, by

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NSF Awards

MARGINS-NSF Awards 2005These are the funded MARGINS Proposals for the fiscal year 2005 as of 17 June 2005. At the time of writing we understand thata number of proposals from 2005 NSF-GEO panels are still pending final decisions. If and when additional awards within theMARGINS Program are announced we will add the details to the MARGINS Awards web page <www.margins.wustl.edu/NSF_MARGINS/AwardNum.html>.

providing support for several graduatestudents and postdoctoral researchers. Wewill involve undergraduate students andgraduate students in the field work, bothat sea and onshore, providing valuablehands-on experience in geophysical dataacquisition. We also propose to involvea high school teacher in the data acquisi-tion on board the Ewing, under the aus-pices of the “Texas Teachers in theField”program. This work will also sup-port NSF’s goals of promoting diversity,gender equity, and mentoring early-ca-reer scientists from underrepresentedgroups by funding at least one femalegraduate student and one female postdoc.

We will contribute to enhanced scientificunderstanding in the geological commu-nity and society by disseminating dataand results from this work in a timely andopen fashion. We will follow the MAR-GINS policies for data dissemination bymaking our data available at cost to in-terested parties within the recommendedtime frames. We will establish and main-tain a web site dedicated to displayingpreliminary results and evolving models.


Our work will help build and strengtheninternational partnerships by promotingcollaborations with researchers overseas.We are cooperating directly withGEOMAR (Kiel Univ., Germany) insharing of instruments and ship time, andwe will collaborate with them in devel-oping from our combined data sets a jointinterpretation of faulting and hydrationon the outer rise of the Subduction Fac-tory. Finally, our work will involve di-rect participation of researchers andstudents from Costa Rica, a developingcountry, in all stages of this work — plan-ning, execution, analysis and publica-tion.searchers and students from CostaRica, a developing country, in allstages of this work — planning, execu-tion, analysis and publication.

NSF Award 0505812

Seismic Structure of the Crust and Up-per Mantle in the Central and North-ern Red Sea Focus Site (RCL)A. Nyblade

Pennsylvania State Univ., UniversityPark

Intellectual Merit: In this proposal, werequest funding to address one of the fun-damental questions in the MARGINSscience plan for Rupturing ContinentalLithosphere (RCL): How is strain parti-tioned during lithospheric rupturing? Wewill address this question for the North-ern/Central Red Sea focus site using 4years (2000-2003) of broadband seismicdata from the Saudi Arabia National Digi-tal Seismic Network (SANDSN) aug-mented by broadband data frompermanent GSN/FDSN/IMS seismic sta-tions in the study area and broadband datafrom recent PASSCAL experiments inEthiopia. The PIs have an agreement withthe operators of the SANDSN networkto use these data for research on crust andupper mantle structure in and around theArabian Peninsula. The SANDSN datacover the period in which PASSCAL ex-periments were conducted in Ethiopia.There are many telesesimic events incommon to these data sets that span theRed Sea, allowing us to extend our in-

vestigation of crust and upper mantlestructure, using surface wave analyses,from the Arabian Peninsula across theCentral Red Sea and into the conjugatemargin on the Sudan side. The data setsare in hand, and combined, they provideus with a unique opportunity to studycrust and upper mantle structure through-out much of the Northern/Central RedSea focus site without incurring the ex-pense of a large seismic field deployment.

To address the key question of how strainis partitioned during lithospheric ruptur-ing, we will analyze and model the broad-band seismic data using proven modelingtechniques for:• Mapping first-order structure

(crust and upper mantle) within,beneath and surrounding theruptured lithosphere.

• Evaluating heterogeneity of thecontinental lithosphere prior torifting.

• Locating seismicity and constrain-ing ambient stress fields andlithospheric rheology.

The data analyses will include joint in-versions of receiver functions and surfacewave dispersion, body wave tomographysurface wave tomography, receiver func-tion stacks of the 410 and 660 km dis-continuities, moment tensor inversionsfor focal mechanisms, and local/regionalwaveform modeling. The results of ourresearch will also provide new insightsinto the processes that led to the break-up of the Afro-Arabian plate, such as therole of the Afar Hotspot.

Broader Impacts: A team of U.S. andSaudi Arabian scientists will workcollaboratively to achieve the scientificgoals of this project. This project will thuspromote scientific cooperation betweenscientists in the U.S. and Saudi Arabia.Exchange visits will be made and paperswill be co-authored. The scientific col-laboration fostered in the project betweenscientists in the U.S. and Saudi Arabiapave the way for students from SaudiArabia to come to the U.S. for graduatetraining. A graduate student will be sup-ported on this project and will be pro-vided with experience working on an

international collaborative project.

NSF Award 0440396

Imaging the Northern Costa Rica Sub-ducted Slab With Broadband ReceiverFunctions (SEIZE)S. Schwartz

University of California, Santa Cruz

Intellectual Merit: Understanding thestate of hydration of subducted lithos-phere is very important due to the likelyrole deep slab dehydration plays in pro-ducing arc lavas and generating interme-diate depth earthquakes within thedowngoing slab. Slab dehydration atshallower depth may also be importantin influencing seismogenic behavioralong the plate interface. Metamorphicdehydration reactions in oceanic crusthave been implicated in theserpentinization of the forearc mantlewedge and the termination of interplateearthquakes in some subduction zones.A major result of the Costa RicaSeismogenic Zone Experiment(CRSEIZE), designed to elucidateseismogenic processes, is the imaging ofa distinct pattern of geodetic locking andmicroseismicity along the plate bound-ary in northern Costa Rica. The onset ofinterplate microseismicity occurs down-dip of the region of geodetic locking andcoincident with the ~250˚C isotherm.This has been interpreted as a down-dipweakening of the plate interface due tofluid production from low-grade meta-morphic reactions in basaltic crustcoupled with a decrease in permeabilityaround 250˚C producing elevated porepressure and sufficient weakening of thethrust interface to permit earthquake fail-ure. The implication of slab dehydrationin the initiation of interplate earthquakeshas thus increased the importance of de-termining the state of hydration of sub-ducting lithosphere. This proposal willanalyze P-to-S converted phases gener-ated at the Moho of the subducting Co-cos slab recorded by CRSEIZEbroadband seismometers positioned di-rectly above the slab. Teleseismic con-verted phases provide a direct method to


image the structure of the subducted slab,and will be used to determine velocitystructure across the oceanic Moho andrelate it to the extent of oceanic crustalhydration. In addition, the velocity struc-ture in the vicinity of the plate boundarywill be investigated and related to theonset of seismicity and the inferred weak-ening of the plate interface.The possiblerole of a large normal fault outer riseearthquake in hydrating the oceanic crustnear the Nicoya Peninsula will also beinvestigated. This work will result in anenhanced understanding of the velocitystructure of the subducting lithosphereand plate interface and itsmaterialproperties.

Broader Impacts: Earth and Ocean sci-entists in numerous disciplines includingseismology, geodesy, structural geology,hydrology, mineral physics and petrologyshare an interest in convergent marginseismogenic zones. Our findings will beof particular interest to these scientistsworking in this environment as well ason processes occurring deeper in subduc-tion zones, such as melt and intermedi-ate earthquake generation. The largestearthquakes threatening increasing popu-lations occur within the seismogenic zoneat convergent plate margins, an improvedunderstanding of its mechanical/fric-tional behavior will impact the field ofearthquake hazard assessment. This re-search will make up a portion of the Ph.D.theses of graduate student Claudia Flores,presently the recipient of a UCSC Costa-Robles minority fellowship, and help toimprove representation of women andminorities in geophysics. Finally, main-taining a funded research project in CostaRica will allow the strong internationalcollaboration between UCSC andOVSICORI-UNA (The Seismologicaland Volcanological Laboratory at theNational University in Costa Rica) tocontinue to thrive. Benefits derived byCosta Rican scientists from previous col-laborations include access to state-of-theart equipment to monitor and analyzeearthquake and geodetic data and the op-portunity to come to the U.S. and inter-act intensely with U.S. scientists.

NSF Award 0505789

Inputs to the Nankai TroughSeismogenic Zone: Effects of Large-scale Lateral Variations in BasementTopography and Sediment Thickness(SEIZE)G. Moore

SOEST, University of Hawaii

Intellectual Merit: We propose to ana-lyze a set of regional 2-D and 3-D seis-mic reflection data across the NankaiTrough accretionary prism to character-ize one of the type examples of a tectonicsetting that globally generates most ofEarth’s largest and most destructiveearthquakes and tsunamis. The proposedwork is a major component of the inte-grated Nankai Trough Seismogenic ZoneExperiment (NanTroSEIZE) that willbuild its solid science base, especially forthe recently highly-ranked shallow non-riser drilling and the deep riser drillingplanned through the Integrated OceanDrilling Program (IODP). With ground-truth from drilling in two existing and oneplanned transect, this seismic data set willprovide unprecedented illumination of aplate boundary fault system to visualizeits geometry, history, and associated rockproperties, as it evolves down dip into aseismogenic zone. We will characterizelarge-scale thrust packages in more land-ward parts of the prism and correlatethem along strike. Our work will not onlyprovide the regional stratigraphic/struc-tural framework of the Nankai Trough,it will also allow us to assess globally-important subduction processes such asthe affect of seamount subduction/colli-sion on accretionary prism evolution.

This project is a collaborative effortamong the University of Hawaii andtwoJapanese institutions (JAMSTEC andUniversity of Tokyo Ocean Research In-stitute). JAMSTEC has already providedus with thousands of km of regional seis-mic lines. Our analysis of these data sea-ward of the Nankai Trough has revealedremarkable variations in oceanic base-ment topography and sediment thicknessand type. We propose to extend our analy-sis of these seismic lines to track the de-

formation of the Nankai accretionaryprism as the ridges and troughs of theShikoku Basin are subducted.

Broader Impacts: Foremost, this projectwill provide significant support for fun-damental goals of the U.S. MARGINS-SEIZE program and the internationalIODP, as outlined in the IODP InitialScience Plan. It builds on strong relation-ships with our Japanese colleagues thatinclude NSF/ODP-funded seismic pro-grams in the Nankai Trough in 1987 and1999.

Support for both graduate and under-graduate students will directly serveNSF’s goals of integrating research andeducation. Students will learn data pro-cessing and interpretation of the 3-D data,and at least one young woman scientistwill be supported.

This project will support seismic dataprocessing/interpretation infrastructure atacademic institutions. In addition, a high-quality data set will be available for theentire U.S. marine geoscience commu-nity. We will contribute to enhanced sci-entific understanding in the geologicalcommunity and society by disseminatingdata and results from this work in a timelyand open fashion. We will establish andmaintain a web site dedicated to display-ing preliminary results and evolvingmodels.

We will also further international coop-eration by strengthening our alreadystrong ties with two Japanese institutions.

Our work addresses seismic hazards inthe heavily populated area of southernHonshu and processes that also generatedestructive earthquakes in the westernU.S., along the Cascadia subductionzone.

NSF Award 0440143

Distinguishing Tectonic Mechanismsof Extension and Forearc Translationnear the Central American VolcanicArc by High-Resolution Seismic Pro-filing in Lakes Nicaragua andManagua (SEIZE)K. McIntosh

NSF Awards


University of Texas at Austin

Intellectual Merit: Upper plate defor-mation at convergent margins frequentlyinvolves some form of arc parallel shear-ing attributed to oblique convergence.This arc-parallel component of obliqueconvergence may be absorbed by defor-mation in the forearc, backarc, or con-centrated along the arc. Two of the majordeformation modes associated with ob-lique convergence are crustal block rota-tion and forearc detachment by strike-slipfaulting along the volcanic arc—theforearc sliver model. The forearc slivermodel is widely supported in theSumatran and Kuril arcs, while interpre-tations of the Aleutian arc initially sup-ported the block rotation model, but newdata suggests arc-parallel strike-slip fault-ing may also be important. In general,although oblique subduction occurs alongparts of almost all subduction zones, themodes of upper plate deformation asso-ciated with it are frequently controver-sial. The Central American convergentmargin is another area affected by obliquesubduction. Here, both block rotation andforearc sliver models have been proposedto accommodate dextral forearc transla-tion, but available data are incon-clusive.The focus of deformation is the Nicara-gua depression, a prominent Quaternarymorphologic and structural depressionaligned with the belt of active CentralAmerican volcanoes, which extendsapproxi-mately 600 km from the north-ern Gulf of Fonseca in El Salvador andnorthern Nicaragua to the Caribbean Seain Costa Rica. To test these two hypoth-eses, we plan to exploit the existence oftwo large, shallow lakes (Nicaragua andAmerican volcanic arc. We propose tocollect roughly 1000 km of high-resolu-tion seismic data using a portableâ€œuniboomâ€� seismic reflection sys-tem mounted on passenger ferries. ThisManagua), which cover a combined areaof ~9000 km2 in Nicaragua. Here thedepression encompasses some of the larg-est, most active, and most intensivelyfaulted volcanoes of the entireCentralwork will map the active faultpatterns in the lakes and allow us to dis-

tinguish between the proposed deforma-tion models.

The block rotation model requires a se-ries of NE striking, left-lateral faultscrossing the lakes. The Tiscapa fault, re-sponsible for the destructive 1972, M6.2earthquake in Managua, is one of sev-eral known left-lateral faults that projectinto the lakes; we will map its extent intoLake Managua and acquire data to de-tect the presence and extent of similarfaults in both lakes. The forearc slivermodel suggests that a major right-lateralfault system is aligned with the activevolcanic chain and that extensional, pull-apart basins will develop between right-stepping arc segments. Thus we willinvestigate the presence of intraarc right-lateral faults and also focus on three ma-jor right-step-over areas in the two lakes.

In addition to testing deformation mod-els related to oblique subduction, we willalso learn about development of the Nica-ragua depression. Some models suggestthat the depression formed largely in Plio-Pleistocene times by arc-normal exten-sion associated with slab rollback.However, if the forearc sliver model ap-plies here, then pull-apart basin develop-ment at right-step-overs along the strikeslip system may also be an important andongoing factor in formation of the Nica-ragua depression. Our data acquisitionwill approach both the NE and SW mar-gins of the lakes to investigate the pres-ence and orientation of basin-formingnormal faults. Although the Matearefault, south and west of Managua, is con-sidered the SW boundary of the depres-sion, we may be able to map subsidiaryfaults in both lakes.

We consider the Nicaragua depression tobe an excellent location to investigatepro- posed models of upper plate defor-mation in response to oblique subduction.Geologic, geodetic, and earthquake stud-ies have made good use of the exposedland areas here, and the water-coveredareas allow efficient seismic data acqui-sition over a wide area. The combineddata sets should lead to true interdisci-plinary progress.

Broader Impacts: Strike-slip earth-

quakes generated by a right-lateral faultzone along the arc or on a series of left-lateral, across arc faults each pose a ma-jor seismic hazard for the populated areasof the Nicaragua depression; the capitalcity and economic hub of Managua hasbeen completely destroyed twice in thelast 70 years by strike-slip events and hasa rapidly growing, present-day popula-tion of over one million inhabitants. Ourwork will better define the modes of ac-tive deformation and will thus help guideseismic hazard mitigation efforts. Thiswork will form all or part of a Master’sproject for a UT graduate student. Thiswill be a collaborative project betweenUT and scientists at INETER, compa-rable to the geologic survey of Nicara-gua. Finally, this study of the Nicaraguadepression component of the CentralAmerican volcanic arc will complementother geologic, geophysical, and geodeticprograms supported by the NSF-Marginsfor the Subduction Factory initiative inCentral America.

NSF Awards 0505987 and 0504465

Collaborative Research: ModelingSediment Delivery and RelatedStratigraphy in a Tidal DominatedDelta: Fly River Papua New Guinea(S2S)S. Fagherazzi1 and I. Overeem2

1Florida State University2University of Colorado at Boulder

Intellectual Merit: The routing of sedi-ments from mountainous areas down tothe continental margin is dictated by sev-eral processes acting at different tempo-ral and spatial scales. In the lower reachesof many rivers tidal fluctuations are thekey factor controlling the delivery ofsediments to the continental shelf, theshape and morphology of the river delta,and the stratigraphy of the accumulateddeposits. In this project we propose todevelop a numerical model to study themorphology, sediment delivery, and re-lated stratigraphy of tidal dominated del-tas. As a case study we will focusoureffort on the Fly River, Papua NewGuinea, one of the community selected


Gulick, S. P. S., A. S. Meltzer, and S. H.Clarke, Jr., 1998. Seismic structure of thesouthern Cascadia subduction zone andaccretionary prism north of theMendocino triple junction, J. Geophys.Res., 103 (B11), 27,207-27,222.

Gulick, S. P. S., N. L. Bangs, T. H. Shipley,Y. Nakamura, G. F. Moore, and S.Kuramoto, 2004. 3-D architecture of theNankai accretionary prism’s imbricatethrust zone off Cape Muroto, Japan: Enechelon thrust accommodation of alongstrike stress regime changes, J. Geophys.Res., 109, B02105, doi:10.1029/2003JB002654.

Kodaira, S., N. Takahashi, A. Nakanishi, SMiura, Y. Kaneda, 2000. Subducted sea-mount imaged in the rupture zone of the1946 Nankaido earthquake, Science, 289,104-106.

Moore, G. F., Shipley, T. H., Stoffa, P. L.,Karig, D. E., Taira, A., Kuramoto, S.,Tokuyama, H., and Suyehiro, K., 1990.Structure of the Nankai Trough accretion-

ary zone from multichannel seismic re-flection data, J. Geophys. Res., 95, 8753-8765.

Moore, G.F., Taira, A., Klaus, A., et al.,2001a. Proc. ODP, Init. Repts., 190 [CD-ROM]. Available from: Ocean DrillingProgram, Texas A&M University, CollegeStation TX 77845-9547, USA.

Moore, G.F., Taira, A., Bangs, N.L.,Kuramoto, S., Shipley, T.H., Alex, C.M.,Gulick, S.S., Hills, D.J., Ike, T., Ito, S.,Leslie, S.C., McCutcheon, A.J.,Mochizuki, K., Morita, S., Nakamura, Y.,Park, J.O., Taylor, B.L., Toyama, G., Yagi,H., and Zhao, Z., 2001b. Data report:Structural setting of the Leg 190 Murototransect. In Moore, G.F., Taira, A., Klaus,A., et al., Proc. ODP, Init. Repts., 190, 1-14 [CD-ROM]. Available from: OceanDrilling Program, Texas A&M Univer-sity, College Station TX 77845-9547,USA.

Moore, G.F., Taira, A., Klaus, A., Becker, L.,Boeckel, B., Cragg, A., Dean, A.,Fergusson, C.L., Henry, P., Hirano, S.,

Hisamitsu, T., Hunze, S., Kastner, M.,Maltman, A.J., Morgan, J.K., Murakami,Y., Saffer, D.M., Sánchez-Gómez, M.,Screaton, E.J., Smith, D.C., Spivack, A.J.,Steurer, J., Tobin, H.J., Ujiie, K.,Underwood, M.B., and Wilson, M.,2001c. New insights into deformationand fluid flow processes in the NankaiTrough accretionary prism: Results ofOcean Drilling Program Leg 190:Geochemistry, Geophysics, Geosystems,2:10.129/2001GC000166.

Moore, J.C., Saffer, D., 2001. Updip limit ofthe seismogenic zone beneath the accre-tionary prism of southwest Japan: An ef-fect of diagenetic to low-grade metamor-phic processes and increasing effectivestress. Geology 29, 183-196.

Obana, K., Kodaira, S., Mochizuki, K.,Shinohara, M., 2001. Micro-seismicityaround the seaward updip limit of the1946 Nankai earthquake dislocation area.Geophys. Res. Lett. 28, 2333-2336.

“3-D” cont. from page 5

focus sites of the Source-to-Sink experi-ment. The Fly River delta is consideredthe archetype of tidal dominated deltas

and the proposed research will becomethe missing link between ongoing stud-ies in the upper and mid Fly River (Dayand Dietrich, 1997; Dietrich et al. 1997;Dietrich et al. 1999) and studies charac-terizing the styles of sediment depositionin the Gulf of Papua (Walsh andNittrouer, 2003; Walsh et al., 2004; Walshand Nittrouer, 2004). This project spe-cifically focuses on the delta morphol-ogy, but also provides a completedescription of how strong signals pro-duced by external factors (climatechange, human activity, sea-level rise)influence the delivery of sediments to theshelf and propagate to the both the low-lands and the continental shelf.

The understanding of the combined in-fluence of tidal, fluvial, and nearshoreprocesses on the sediment transport andstratigraphy of tidal dominated deltas willanswer the following fundamental ques-tions:

What filter or transport function does thedelta provide between the episodic inputs

of sediments from upland areas and theoutput to the continental shelf? Whatmechanisms are responsible for the com-plex morphology of tidal dominated del-tas? What processes form the elongatedislands and tidal channels characteristicof tidal deltas? How is the variability ofsediments preserved in thestratigraphicrecord of a tidal dominateddelta? How does the delta system respondto climaticfluctuations, sea-level rise, andhuman activities?

The research activities will include:

i) Modeling the morphological develop-ment of the Fly tidal delta and the stylesof sediment accumulation within the deltaii) Characterizing the amount and vari-ability of sediment outputs from the river-delta system to the shelf iii) Determiningthe influence of sea-level rise, climaticfluctuations, and human activities ondelta morphology and stratigraphy.

Broader Impacts: The understanding ofthe mechanisms of sediment transportand deposition in tidal dominated deltasis of critical importance for the combinedmorphological and ecological equilib-rium of coastal areas. The evolution of

tidal deltas is often dictated by a delicateequilibrium between vegetation and sedi-ments. Fish productivity is also affectedby sediment concentration in the watercolumn, so that a variation in sedimentload and sediment availability has reper-cussions on different aspects of coastalecosystems. A morphological model oftidal dominated deltas is an importanttool for assessing the impact of humanactivities on coastal areas. Consequencesof mining activities, construction of arti-ficial dams, removal of sediment-stabi-lizing vegetation, automatically alter thedelta sediment budget. These modifica-tions often produce coastal erosion, witha high societal impact. The systemreponse to sea-level rise and climaticfluctuation will finally provide possiblescenarios for the future evolution of tidaldeltas and related consequences for hu-man settlements.

The proposed research contributes toeducational programs in two universitiesthat involve both graduate and under-graduate students. The models and re-lated results will be made available in aCD ROM as an educational tool for K-12 and college students.

NSF Awards


“Chair” cont. from page 7

also contribute to SubFac progress in theregion. MSC members note the impor-tance of testing hypotheses of massiveslab serpentinization at the outer rise, in-vestigating the intrusive component ofcrustal growth at volcanic arcs, integrat-ing gravity and magnetic data, and es-tablishing complete heat flow transectsacross the forearc and arc to constrainthermal modeling. The MSC is lookingtowards an integrative TEI in 2007. Asuccessful event response was completedat Anatahan in the Marianas in March,including flux monitoring of volcanicgases and sampling of recent eruptives(see pages 12-13).

Relationship with OtherPrograms

With SEIZE and SubFac (the earliestof the MARGINS initiatives) maturingso well, it makes sense to consider whatcomes next. Possible directions couldcome from consideration of initiativeselsewhere in the GEO Directorate atNSF, which have science goals overlap-ping MARGINS interests. The article onrelated programs (page 22) reflects inpart presentations made to the MSC atthe April meeting by Greg van der Vinkof Earthscope, Rich Jahnke of the OceanObservatories Initiative (OOI) andHarold Tobin representing theNanTroSEIZE IODP Riser-drillinggroup. We also discussed plans andprogress in the Community Surface Dy-namics Modeling System and the Centerfor Geo-informatics efforts, focused ondeveloping community resources for so-phisticated modeling of Earth surface anddeep Earth processes.

Natural collaborations withEarthscope occur in the Gulf of Califor-nia/Salton Trough focus site, and are ef-fectively already underway, with a15-month MARGINS-funded deploy-ment of OBSs in the Gulf, commencingin October of this year. Additional ma-rine seismic work, particularly in thenorthernmost Gulf would certainly bedesirable. Proposals to use theEarthScope flexible array to better con-

strain structure and tectonics in the SaltonTrough region would also be helpful.Other possibilities for collaboration in anext generation MARGINS Program in-clude Cascadia and the Aleutians, alliedfocus sites for the Subduction FactoryScience Plan, where seismic and geodeticinstruments are being deployed betweennow and 2008 (see page 22 for furtherinformation). The Ocean ObservatoriesInitiative would include a coastal obser-vatory component with technologyhighly relevant to S2S, as well as thecabled observatories being proposed forthe Juan da Fuca plate/Cascadia margin.The Canadian NEPTUNE deployment onthe Juan da Fuca plate is expected to be-come operational in 2008.

Clearly, any next steps for MARGINSwill be the result of extensive commu-nity discussion, with NSF guidance. Anext program would need to have newguiding visions, rather than just wrappingup unfinished efforts. A first priority forMARGINS must be to do justice to allthe current initiatives and the next stepsmay be some distance down the road. Butwe wanted to share with you some of theMSC’s thinking about the long-term fu-ture of MARGINS; we’d like to hear yourthoughts on the subject.

Rotations

Saying good-bye is always difficult.Pat Wiberg has rotated off the steeringcommittee, and we will miss her insightinto rapid sedimentary processes, herunderstanding of data needs on the sub-aerial end of the S2S system and herthoughtful guidance. Jeff Ryan, from theUniversity of South Florida, and a nowfinishing rotator at NSF’s Division forUndergraduate Education, will rotateonto the MSC. Please nominate yourselfor someone else for the MSC at any time.I’m also dismayed but pleased that LauraKyro is leaving the MARGINS Office,having translated her short-term job withMARGINS into a permanent position atWashington University. We will missLaura’s unique combination of superborganizing skills and great artistic anddesign ability. Congratulations and best

of luck Laura. Laura’s job will be filledby Meredith Berwick. Meredith is a re-cent Washington University graduate inEnvironmental Studies, interested in add-ing science planning and education to heracademic background.

and industry to focus on the geologicalevolution of ocean margins. LINK is theUK Government’s principal scheme forpromoting industry-academia researchpartnerships in order to maximize thevalue of industry-generated data fourteenfull projects and nine stand-alonestudentships have been funded.

The Programme has three mainthemes: deep structure and rifting; sedi-mentary processes; and fluid flow.Multidisciplinary interests include im-proved prediction in exploration and res-ervoir characterization, gas hydrates as ahazard and potential energy source, pre-diction of deepwater geohazards, and sus-tainable management of hydrocarbonresources and the deep-water environ-ment.

Research partnerships that can con-tinue beyond the scheduled end of OMLin late 2006 are a priority. Links have al-ready been forged with IODP,Euromargins, and InterMARGINS. OMLplans to hold a conference in early 2006inviting leaders in margin research to dis-cuss global margin research themes. Thisconference may be of interest to MAR-GINS scientists.

An article introducing OML and re-viewing the ‘Pushing the Margins’OML Workshop, London, 16 Nov.2004, by Dr. Alick Leslie, OML ScienceCo-ordinator, British Geological Sur-vey, Edinburgh, is available online at:www.margins.wustl.edu/Meetings/OML.html

-PW

“Related” cont. from page 22


would be easy, but once we got familiarwith the technical aspects of web pages(movie making, editing, transmitting dataand working on web pages), we foundit’s really not that difficult.”

I asked David how the time spent onthe web expeditions fitted in with the rig-ors of fieldwork: “After each day of field-work, when we would normally bewinding down - after a long hike or drivefor example - everyone got together andcataloged the day’s activities in wordsand pictures with the help of Wayne[Suiter] and Joe [Hlebica]. On our sec-ond virtual expedition (to the Marianas)we didn’t have support people with us inthe field so the workload (filming, edit-ing, writing) was shared between the ex-pedition participants. It involved thesame amount of work as the first expedi-tion – both before and during the field-work.”

Despite being the first efforts at out-reach of this type for most of those in-volved (including David), the webexpeditions show a maturity of designand content that belies the steep learningcurve. From David’s answers, it’s clearthat having everyone enthusiastic andonboard with the effort both in the fieldand at Scripps is what made the web ex-peditions so successful.

David is careful to thank those whohave supported the web expeditions:“The Scripps Web Operations Group [ledby Wayne Suiter] has been very support-ive of our endeavors. They provide theserver, help with the design of the webpages, contribute to the writing and lookafter the technical aspects of the project.In the Marianas, the technical staff of theR/V Wecoma ship helped us transmit databy satellite. . . Various colleagues and stu-dents have also been willing participantsin the virtual expeditions. Toby Fischer(University of New Mexico) and AlisonShaw (ex-Scripps, now [a MARGINSPostdoctoral Fellow at] Carnegie Insti-tution) were involved in both Costa Ricaand the Marianas [expeditions].

“I hope we’ve been able to convey thefun of doing science in the field. The di-

versity of people following our web castshas been incredible – from NSF programmanagers in Washington, DC to kids inthe outback in Australia. We have hadmore that 170,000 individual visits to theCosta Rica site (in 4 years). . . I thinkmany people are now aware of the kindsof research that goes on within universi-ties.” David continues, “I know that somegeology programs use the web pages aspart of their curriculum. That’s a greatway to get people interested in geology.Maybe future graduate students will beintroduced to the subject by going on webexpeditions?”

With regard to the future, David willhelp produce a web expedition to the IzuIslands of Japan to accompany MAR-GINS-related work this summer (2005).He notes that not every trip is suited toweb expeditions because of practical andtechnical considerations, but he hopes todo more in future. There are also otheravenues he’d like to explore, such as run-ning short courses at local universities/colleges or involving school kids andtheir teachers in his team’s work.

“Every proposal has a ‘Broader Im-pacts’ segment to it. As long as the req-uisite funding can be raised and [theparticipants accept the] commitment in-volved then such expeditions should be-come (and are in fact becoming) morecommon.”

What’s David’s best advice to othersseeking to add outreach to their research?“Just do it.”

David Hilton’s web expeditions have beenfeatured by Yahoo! Kids and have beenExploratorium’s ‘Cool site of the Month’<www.exploratorium.edu>.

The Costa Rica and Mariana field expedi-tions were funded by NSF. Scripps sup-ported the web expedition to Costa Rica,and the Marianas web expedition wasfunded through an outreach funding re-quest to NSF.Central America expedition participants:• Scripps Institution of Oceanography:

David Hilton, Alison Shaw, JoeHlebica and Wayne Suiter Matamoros.

• University of New Mexico, Albuquer-que: Tobias Fischer and Mindy

Zimmer.

• Northern Illinois University, DeKalb:Jim Walker.

• Instituto Costarricense de Electricidad,Costa Rica: Guillermo AlvaradoInduni.

Marianas expedition participants:• Scripps Institution of Oceanography:

David Hilton, Lillie Jaffe

• Boston University: Jennifer Wade.

• Carnegie Institution: Erik Hauri,Alison Shaw

• University of New Mexico: TobiasFischer, Maarten de Moor.

The MARGINS Office plans to featureMARGINS Education and Outreach lead-ers in future Newsletters. Nominations,including self-nominations, may be madeby e-mail to [email protected].

“Hilton” cont. from page 17

level, because many objectives in theIBM forearc and backarc basin lie at sig-nificantly greater water depths.

With a carefully chosen site, therecould be other important features of theIBM Focus Area to drill, either on theway to the Moho, or on their own. Forexample, drilling opportunities in IBMmight investigate subduction initiationproducts and arc evolution from its ear-liest development (> 50 Ma) onwards. Atonalite layer could be drilled in an in-tra-oceanic setting. Whatever the deep-est target, the community would have tobe convinced of the scientific importanceof the whole column, not just the ulti-mate target.

The conveners closed the mini-work-shop with high hopes for quality propos-als from the community to address theexcellent scientific drilling opportunitiespresented by Chikyu and the IBM FocusArea. Morris suggested that the commu-nity might consider a full workshop inthe near future to consider how best toutilize these opportunities to the best in-terest of the defined Subduction Factorygoals.

“MARGINS-IFREE” from page 25


MARGINS Steering Committee

Bilal HaqMarine Geology and Geophysics Program

Division of Ocean SciencesTel: (703) 292-8582Fax: (703) 292-9085

e-mail: [email protected]

Rodey BatizaOcean Drilling Program

Division of Ocean SciencesTel: (703) 292-8581Fax: (703) 292-9085


David FountainTectonics Program

Division of Earth SciencesTel: (703) 292-8552Fax: (703) 292-9025


NSF Program DirectorsNational Science Foundation, 4201 Wilson Boulevard, Arlington, Virginia 22230

This information is also posted on the MARGINS website, where it is continuously updated.

Contact Information

Julie Morris, ChairDepartment of Earth and Planetary SciencesWashington University in St. LouisCampus Box 1169One Brookings DriveSaint Louis, MO 63130Tel: (314) 935-6926e-mail: [email protected]

Geoffrey AbersDepartment of Earth SciencesBoston University685 Commonwealth AvenueBoston, MA 02215Tel: (617) 353-2616e-mail: [email protected]

Peter van KekenDepartment of Geological Sciences425 East University AvenueUniversity of MichiganAnn Arbor, MI 48109-1063Tel: (734) 764-1497e-mail: [email protected]

Paul J. UmhoeferDepartment of Geology, Box 4099Northern Arizona UniversityFlagstaff, AZ 86011Tel: (928) 523-6464e-mail: [email protected]

Uri S. ten BrinkU.S. Geological Survey384 Woods Hole Rd.Woods Hole, MA 02543 USATel: (508) 457-2396e-mail:[email protected]

John MillimanVirginia Institute of Marine ScienceCollege of William and MaryP.O. Box 1346Cloucester Point, VA 23062Tel: (804) 684-7105e-mail: [email protected]

Lincoln PratsonDivision of Earth and Ocean SciencesDuke University203 Old Chem Bldg, Box 90230Durham, NC 27708-0277Tel: (919) 681-8077e-mail: [email protected]

Don ReedDepartment of GeologySan Jose State UniversitySan Jose, CA 95192-0102Tel: (408) 924-5036e-mail: [email protected]

Rudy SlingerlandDepartment of GeosciencesPenn State University503 Deike BldgUniversity Park, PA 16802Tel: 814-865-6892e-mail: [email protected]

Julia K. MorganDepartment of Earth Science, MS-1266100 Main StreetRice UniversityHouston, TX 77005-1892Tel: (713) 348-6330Houston, TX 77005-1892email: [email protected]

W. Roger BuckLamont-Doherty Earth ObservatoryRt. 9WPalisades, NY 10964Tel: (845) 365-8592e-mail: [email protected]

Mike BlumDepartment of Geology and GeophysicsE235 Howe-Russell Geosciences ComplexLouisiana State UniversityBaton Rouge, LA 70803Tel: (225) 578-5735e-mail: [email protected]

Mark ReaganDepartment of GeoscienceUniversity of IowaIowa City, IA 52242Tel: (319) 335-1802e-mail: [email protected]

Liz ScreatonDepartment of Geological SciencesUniversity of Florida241 Williamson, Box 112120Gainesville, FL 32611Tel: (352) [email protected]

MARGINS OfficeWashington University in St. Louis, Department of Earth and Planetary Sciences

1 Brookings Drive, CB 1169, St. Louis, MO 63130Tel: (314) 935-9367, Fax: (314) 935-7361, E-mail: [email protected],Website: www.margins.wustl.edu

Jeff RyanDepartment of GeologyUniversity of South Florida4202 East Fowler Ave., SCA 528Tampa, FL 33620-5201Tel: (813) 974-1598/6287e-mail: [email protected]

This newsletter is supported by the National Science Foundation underGrant No. OCE 03-25002. Any opinions, findings, and conclusionsexpressed in it are those of the authors and do not necessarily reflect theviews of the National Science Foundation.

Upcoming Meetings:AGU Fall Meeting 2005

San Francisco, California, December 5–9, 2005www.agu.org/meetings/fm05

RCL Gulf of California WorkshopEnsenada (Mexico), January 9-13, 2006

www.rcl-cortez.wustl.edu

MARGINS OfficeWashington University in St. Louis

1 Brookings Drive, CB 1169

St. Louis, MO 63130 USA

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This newsletter is produced on behalf of MARGINS by the MARGINS Office:Editors: J. Morris <[email protected]> and P. Wyer <[email protected]>Composition, graphics, and sub-editing: L.Kyro and M. Berwick<[email protected]>

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