eos_leyte_landlside_2006.pdf

8/10/2019 eos_leyte_landlside_2006.pdf

1/10

A massive landslide devastated the commu-nity of Barangay Guinsaugon, Municipality ofSt. Bernard, Southern Leyte Province, Philip-pines, at about 10:30 local time on 17 February.The landslide occurred along the steep faultscarp of the Philippine Fault Zone (PFZ) (Fig-ure 1a), a large and active tectonic structurethat traverses the entire length of the Philip-pines [Allen, 1962]. Barangay Guinsaugon islocated at the foot of the scarp, directly in thepath of the downward moving mass of earth.As of 24 February, the landslide caused 122confirmed deaths; 1,328 people still are missing.

To assist in the search and rescue operationsthat followed the landside, a team of geologistsand physicists from the University of Philippines(UP-Diliman, Quezon City) and Ateneo deManila University conducted an investigation ofthis area on 2125 February. The UP-Ateneoteam provided technical advice on the geology,

which included the identification of the typeand characteristics of the landslide.

The Guinsaugon Rockslide-Debris Avalanche

Satellite imageries taken in 2003 and 2004show traces of two prominent structures, thenorth-northwest trending PFZ and a north-west trending structure oblique to the PFZ(Figure 1a and 1b). The horseshoe-shapedfeature found along the trace of the obliquestructure, at an elevation of 675 meters, is thesite of the recent landslide. Another horse-shoe-shaped feature, 500 meters south-south-east of the present landslide head, is perhaps

an old landslide scar (Figure 1b).The landslide has a planform area ofapproximately three million square meters anda distance of 4.0 kilometers from the crown totoe. It has a thickness of 67 meters near thetoe and 30 meters at the base of the fault scar(Figure 2a). The volume of the deposit is in theorder of 1520 million cubic meters. On the

basis of accounts from residents of the area ofthe duration and the distance traveled by thelandslide, the flow velocity was approximately100140 kilometers per hour.

The main sliding plane of the avalanche isa prominent north-northeast oriented planeat the head of the landslide intersected at anangle by a less planar feature (Figures 1c and1d). The more planar surface exhibits slicken-sides (striations indicating movement) of aleft-lateral fault. Below the crown are terracescomposed of slope material that moveddownward along sliding planes. The fan orfoot portion of the slide has ridges, radial

VOLUME 87 NUMBER 12

21 MARCH 2006

PAGES 121128

Eos, Vol. 87, No. 12, 21 March 2006

!"#$ &'()#(*&+")#$ (,!'+*() -!"./0#+*(1 2)+")

PAGES 121, 124

Scientists Investigate RecentPhilippine Landslide

BYA. M. A. LAGMAY, J. B. T. ONG, D. F. D. FERNANDEZ,M. R. LAPUS, R. S. RODOLFO, A. M. P. TENGONCIANG,J. L. A. SORIA, E. G. BALIATAN, Z. L. QUIMBA, C. L.UICHANCO, E. M. R. PAGUICAN, A. R. C. REMEDIO,G. R. H. LORENZO, W. VALDIVIA, ANDF. B. AVILA

Fig. 1. (a) Shaded relief image generated from a Shuttle Radar Topography Mission (SRTM) digi-tal elevation model with interpreted northwest lineaments (white dashed lines) intersecting the

Philippine Fault (black solid line); (b) False-color Landsat image that delineates the pre-landslidescar where the Guinsaugon landslide originated. The pre-2006 landslide scar (white dotted line)is found northwest of an older landslide scar (indicated by arrow). Raw image data were takenfrom http://www.landcover.org; (c) Oblique aerial photo showing the relative positions of the

Philippine Fault and the town of Guinsaugon with respect to the landslide. Raw image courtesyof Michael D. Kennedy (U.S. Navy). http://www.navy.mil/view_single.asp?id=32073; (d) Close-upview of the landslide head.


2/10

Eos, Vol. 87, No. 12, 21 March 2006

Fig. 2. (a) Schematic of the landslide at Guinsaugon, Leyte, showing the main parts of the depositand the approximate location of Barangay Guinsaugon before and after the event; (b) Radialcracks at the southern distal part of the landslide; (c) Rescuers search for survivors below ahummock field. Inset shows a six-meter-wide by three-meter-high hummock.

cracks (Figure 2b), and numerous hills knownas hummocks (Figure 2c). The deposit is com-posed of volcanic rocks from the Leyte Cen-tral Highland Volcanics, sedimentary rocks of

the Calian Formation, and breccias producedby the movement of the Philippine Fault (e.g.,J. D. Azares et al. (Southern Leyte revisited:New geologic data and insights, unpublishedreport 2003; R. M. Saturay Jr. and R. A. TamayoJr. (Southern Leyte field and structural evi-dence for major Cenozoic tectonic events inthe Philippines, unpublished report, 2003)).On the basis of these characteristics, the land-slide was identified as a rockslide-debrisavalanche.

The Guinsaugon rockslide-debris avalancheis the second major landslide of this kind tobe described in the twenty-first century, andthe volume of its deposit falls within the rangegenerated by debris avalanches from the twen-tieth century that are examined here. Deaths,casualties,and other damages associated witheach of these events are listed in Table 1.

Causal Mechanisms

The factors suspected to have triggeredthe Guinsaugon rockslide-debris avalancheare rainfall and a 2.6 magnitude earthquake.Multi-satellite precipitation analysis from theNASA-Japan Aerospace Exploration AgencyTropical Rainfall Measuring Missionreportedthat 500 millimeters of rain fell in SouthernLeyte between 4 and 7 February. The Philippine

Atmospheric, Geophysical, and AstronomicalServices (PAGASA) rainfall station at Otikon,located seven kilometers southwest of thehead of the landslide, recorded 683.6 millime-

ters from 814 February. The highest rainfallover this duration was 171 millimetersrecorded on 12 February (Figure 3a).

The earthquake reported by the PhilippineInstitute of Volcanology and Seismologyoccurred 25 kilometers west of the landslidearea around the time of the event. However,this earthquake may have been too weak anddistant to have caused the landslide. A properassessment can be made on the significanceof the earthquake as a trigger of the landslidewhen the exact time of the event is deter-mined and available seismic data is reviewed.

It is also worth mentioning that residentsfrom Barangay Guinsaugon reported that theriver in between the base of the fault scarpand Barangay Guinsaugon dried up two daysbefore the landslide incident. Local mountaintribesmen also reported having felt an earth-quake two months prior to the disaster andnoticed cracks on the ground. River andmeteoric water may have seeped into thesefractures and lubricated the slip planes.

An inventory of the location of the survi-vors, fatalities, and personal articles of thevictims shows transport by the rockslide-debris avalanche toward the toe of thedeposit. Houses, including a three-story con-crete building in front of the Barangay Guin-saugon grade school, were transported 550600

meters southeast from their original posi-tions. Many collapsed houses found at ornear the surface were transported downslopebut remained relatively intact with minimal

scattering. Neighboring houses that moveddownward remained adjacent to each other.A refrigerator and a computer were foundwhole. These data suggest an en masse trans-port of the community.

Hazards

Ground-penetrating radar surveys con-ducted five days after the landslide at theoriginal site of Barangay Guinsaugon indi-cate groundwater level at 1415 metersbelow the present surface. Groundwater iscloser to the surface at the distal portion ofthe rockslide-debris avalanche deposit. Heavyrainfall continued to saturate the debrisdeposit, causing an elevation of the watertable, an accumulation of water at the surfaceof the deposit, and an increase in stream dis-charge, which may trigger mudflows andmake retrieval operations difficult and dan-gerous (Figure 3b, item 1). Unstable materialon the main scarp and on steep slopes mayalso cause subsequent smaller landslides tooccur (Figure 3b, items 2 and 3).

Acknowledgments

We thank the Luis A. Yulo Foundation,Southern Leyte Governor Rosette Lerias, the


3/10

Eos, Vol. 87, No. 12, 21 March 2006

Philippine Army, the U.S. Marines, the Philip-pine Long Distance Company, the PhilippineNational Red Cross, the Provincial DisasterCoordinating Council, the Armed Forces ofthe Philippines Reserve Command, the Phil-ippine Department of Natural Resources,Secretary Angelo Reyes, the Asian DisasterPreparedness Center, the German TechnicalCooperation, Earthprobe Inc., Republic Bis-cuit Company, civilian volunteers, and the

rescue teams from Indonesia, Malaysia,Spain, Taiwan, and Turkey for supporting thesearch and rescue effort. We also thank JoseRamon T. Villarin, S.J., Daniel J. McNamara, S.J.,Emmanuel G. Anglo, Mariano A. Estoque,Tristan Calasanz, Gerald A. Galgana, andGemma T. Narisma of the Manila Observa-tory, Philippines, for providing daily weatherreports and advice.

References

Allen, C. R. (1962), Circum-Pacific faulting in thePhilippine-Taiwan region,J. Geophys. Res., 67,47954812.

Christiansen, R. L., and D. W. Peterson (1981), Chronol-

ogy of the 1980 eruptive activity: The 1980 eruptionsof Mount St. Helens, U.S. Geol. Surv. Prof. Pap., 1250.Nakada, S. (2000), Hazards from pyroclastic flows and

surges, inEncyclopedia of Volcanoes,edited byH. Sigurdsson et al., pp. 945955, Elsevier, New York.

Schuster, R. L. (1996), The 25 most catastrophic land-slides of the 20th century, inLandslides: Proceed-ings of the 8th International Conference and FieldTrip on Landslides,edited by Chacon et al., A. A.Balkema, Brookfield, Vt.

U.S. Geological Survey (2004), November 7, 2002,flight observations of M7.9 Denali Fault earth-quake, Glacier and Snow Program. (Available athttp://ak.water.usgs.gov/glaciology/m7.9_quake/nov_7_flight_desc.htm)

Voight, B. (2002), Honoring the memory of DavidVarnes: The Boxing Day 1997 sector collapse,debris avalanche, and depressurization blast onMontserrat, BWI, paper presented at the GeologicalSociety of America Annual Meeting, Denver, Colo.,2730 Oct. (Available at http://gsa.confex.com/gsa/2002AM/finalprogram/abstract_36155.htm)

Author Information

Alfredo Mahar A. Lagmay, National Institute ofGeological Sciences, University of the PhilippinesDiliman, Quezon City, E-mail: [email protected]; John Burtkenley T. Ong and Dan FerdinandD. Fernandez, Manila Observatory, Ateneo deManila University Campus, Loyola Heights, QuezonCity; Mark R. Lapus, Raymond S. Rodolfo, Arlene

Mae P. Tengonciang, Janneli Lea A. Soria, Eden G.Baliatan, Zareth L. Quimba, Christopher L. Uichanco,and Engielle Mae R. Paguican, National Institute ofGeological Sciences, University of the PhilippinesDiliman; Armelle Reca C. Remedio, Genevieve

Rose H. Lorenzo, and Francia B. Avila, ManilaObservatory, Ateneo de Manila University Campus;and Waldemar Valdivia, National Institute of Geo-logical Sciences, University of the PhilippinesDiliman.

Fig. 3. (a) PAGASA Rainfall data at Otikon Station from 819 February 2006 shows an accumulatedrainfall of 674 mm by 17 February 2006.; (b) Identified hazards: (1) ponding and an increase indischarge and mudflow; (2) potential landslide on the main scarp; and (3) steep slopes.


4/10

Eos, Vol. 87, No. 12, 21 March 2006

YearCountry(State/

Province)

Name & Type(s)Triggering

Process

Volumeof material

(m3)

Impact Comments

1962 Peru (Ancash)

Nevados

Huascaran debris

avalanche

Unknown 13 x 1064,0005,000 killed; much of villageof Ranrahirca destroyed.

Major debris avalanche from a

local mountain, average velocity

170 km/hr.

1970 Peru (Ancash)Nevados

Huascaran debris

avalanche

Earthquake (M7 .7) 3050 x 10618,000 dead; town of Yungaydestroyed; Ranrahirca partially

destroyed.

Debris avalanche from same peakas in 1962; average velocity 280

km/hr.

1974Peru

(Huancavelica)Mayunmarca rockslide-

debris avalancheRainfall?

River erosion?1.6 x 109

Mayunmarca village destroyed, 450

killed; subsequent failure of 150-m-high landslide dam caused major

downstream flooding.

Debris avalanche with average

velocity of 140 km/hr dammed

Mantaro River.

1980United States

(Washington)

Mount St. Helens rockslide-

debris avalanche

Eruption of Mount St.

Helens (Note: AM5.0earthquake preceded

the landslide event)[Christiansen andPeterson, 1981]

2.8 x 109

Worlds largest historic landslide;

only 510 killed, but major destruc-tion of homes, highways, and so

forth; major debris flow; deaths low

because of evacuation.

Evacuation saved lives; began as

rockslide; deteriorated into 23-km-long debris avalanche with aver-

age velocity of 125 km/hr; surfaceremobilized into 95-km-long debris

flow.

1986

Papua, New

Guinea (EastNew Britain)

Bairaman rockslide-

debris avalanche

Bairaman earthquake

(M7.1)200 x 106

Village of Bairaman destroyed bydebris flow from breached landslide

dam; evacuation prevented casual-

ties; huge effect on local landscape.

Debris avalanche formed 210-m-

high dam that impounded 50-mil-

lion-m3lake; dam failed, causing100-m-deep debris flow-flood

downstream.

1997

Soufrire HillsVolcano,

Montserrat,

West Indies

Soufrire Hills debris

avalanche

Growth of a lava lobe

and build-up of lava-block talus

64 x 106

The possibility of an edifice col-lapse was recognized in 1996, and

a precautionary evacuation in late1996 prevented loss of life in this

violent event.

Debris avalanche emplaced in

three minutes at an average speedof 40 m/s.

2002 Central Alaska Rock debr is avalanchesM7.9 Denali Fault

earthquake1070 x 106

Occurred in an isolated national

park.

Three, largely rock debris ava-

lanches crossed almost the entireone-mile width of Black Rapids

Glacier; total glacier area covered

with rock debris is about 13 km2.

2006Guinsaugon,

Southern Leyte,

Philippines

Guinsaugon rockslide-

debris avalanche

Rainfall and earth-quake. Lubrication of

fault plane by water.

1520 x 106

Barangay Guinsaugon, St. Bernard

destroyed with population of 1,857;as of 24 February 2006: 122 bodies

retrieved, 410 survived of which 20

were rescued; 1,328 still missing.

The debris avalanche transporteddownslope en masse Barangay

Guinsaugon 500600 m southwest

of its original location. Its flowvelocity is estimated at 100140

km/hr.

Table 1. Major Debris Avalanches in the 20th and 21st Centuries. (Modified fromSchuster[1996], with the addition of theSoufrire Hills [Nakada, 2000; Voight, 2002], Denali [U.S. Geological Survey, 2004], and Guinsaugon debris avalanches.)


5/10

Eos, Vol. 87, No. 12, 21 March 2006

The critically endangered ivory-billed wood-pecker (Campephilus principalis) apparently

has been rediscovered in old-growth baldcypress (Taxodium distichum,Figure 1) andswamp tupelo (Nyssa aquatica) forests of Bay-ou DeView, located seven kilometers north-west of Brinkley, Ark. [Fitzpatrick et al.,2005].The evaluation of the impact of drought onforest history and wildlife population levels iscritical to the conservation of the ivory-billedwoodpecker and other similarly endangeredspecies. Tree ring chronologies have beendeveloped from old-growth forests at BayouDeView to aid in this assessment.

This article also describes a conceptualmodel that has proven useful for the dis-covery of other noncommercial old-growth

cypress-tupelo remnants in the Southeast.These relict cypress-tupelo stands may becandidates for conservation, restoration, andperhaps the eventual reintroduction of theivory bill and other increasingly rare speciesnative to this ecosystem.

Tree Ring Chronologies and Drought

For this study, tree ring chronologies weredeveloped at three sites in the Western Low-lands of northeast Arkansas (Figure 2a), thearea that contains Bayou DeView. The chronol-ogies are all at least 850 years long, and werebased on core samples from centuries-old liv-ing bald cypress trees and fallen logs.

The simple mean ring-width chronologiesexhibit the slow centuries-long decline inradial growth rates typical of trees that matureand senesce in a natural forest setting (Fig-ure 2a). Bald cypress radial growth is drivenprimarily by precipitation during the growingseason [Stahle and Cleaveland, 1992], andrecent research indicates a similar responsefor tupelo. However, the mean and varianceof the simple mean ring-width chronologiesincrease in the twentieth

century, especiallyat Bayou DeView and at another WesternLowlands area, Mayberry Slough (Figure 2a),which may reflect both precipitation changesand human alterations of the drainage basin.

The three bald cypress tree-ring chro-nologies are significantly cross-correlatedand have been used to develop a regionalring-width index chronology, where non-cli-matic growth trends have been removed withdetrending and standardization (Figure 2b).The three most severe episodes of low growthin the Western Lowlands occurred during thefourteenth, fifteenth, and sixteenth centuries(Figure 2b).

The severe sustained droughts of the four-teenth and fifteenth centuries were concen-trated over the central United States (Figure 2c;Cook et al.[2004]) and appear to have shaped

the age structure of the oldest bald cypress stillsurviving along Bayou DeView. Both droughtslasted for 10 consecutive years and must havecaused the deaths of millions of forest trees inthe lower Mississippi Valley. Though only a frac-tion of the living bald cypress exceed 600 yearsin age (Figure 2b), the oldest bald cypress ger-minated before 1380 A.D. and appear to be thelast living members of a cohort that survivedthe extreme fourteenth- and fifteenth-centurydroughts.

The Effects of Decadal Drought

These decadal droughts may have created

the ideal conditions for cypress regeneration.Bald cypress is a tree of even-age groupswithin all-age stands [Mattoon, 1915]. Cypressis exceptionally long lived, but cypress seedswill not germinate in water, and seedlingswill not tolerate prolonged inundation. Con-sequently, old-growth cypress forests oftenincluded distinctive cohorts of even-age treesthat regenerated infrequently when low waterconditions persisted sufficiently long for bothgermination and seedling height growth. Theinner ring and pith dates for many cypress inthe Western Lowlands date soon after thesedroughts (Figure 2b). All cores were takenabove the basal swell of the tree and under-

estimate the true age of germination. Nev-ertheless, most of these trees, and no doubtmillions of other cypress in the Western Low-lands, probably germinated during the pro-longed drought and low water conditions ofthe fourteenth- and fifteenth-century droughts.

Ivory bill numbers also likely increased inthe wake of the decadal droughts. Ivory-billedwoodpeckers feed predominantly on wood-boring larvae in the Cerambycidae, Bupresti-dae, and Elateridae beetle families, especiallyin large old trees subject to decay and inrecently dead trees [Tanner, 1942]. Earlytwentieth century observations indicate thatthe abundance of beetles and ivory bills bothincreased in areas with recently killed stand-ing timber [Tanner,1942]. Other species alsorespond to disasters, including Bachmanswarbler (Vermivora bachmanii, now likelyextinct), which seems to have increased innumbers following habitat changes caused bythe New Madrid and Charleston earthquakesof 18111812 and 1886, respectively [Shugart,2004].

Old-Growth Cypress-Tupelo Conservation

Bald cypress grew in a variety of wetlandconditions and produced several grades of

cypress lumber, some of which was morevaluable for timber production than others(Figure 3). The commercially valuable virgincypress forests with tall columnar trees werea preferred habitat for ivory-billed woodpeck-ers [Tanner, 1942] and were among the mostheavily logged forest ecosystems in the world.Very few stands of virgin bald cypress withhuge trees have been preserved.Mattoon[1915] estimated that the permanent swampecosystem of the South covered nearly 17 mil-lion hectares, but it is estimated that no more

than 5000 hectares of virgin cypress remain,perhaps only 0.0002% of the original uncutecosystem. The best cypress growth was oftenobserved in the large back swamps away fromthe main stream channels where cypress treeswere obliged to grow under an unbrokencanopy over 30 meters high, producing theremarkable forests of tall, clear cypress stems(free of branching) so heavily exploited forlumber production.

Only three reasonably large tracts of virgincypress with commercial grade timber areknown to remain: a 1400-hectare tract on pri-vate property in southwestern Arkansas; andthe National Audubon Society sanctuaries atFour Holes Swamp, S.C. (713 hectares), and atCorkscrew Swamp, Fla. (283 hectares).

Fortunately, a few small stands of old, over-mature bald cypress and tupelo in noncom-mercial settings survived the era of massivetimber cutting and agricultural land clear-ing. The old-growth cypress-tupelo at BayouDeView have suffered selective logging (pri-marily for tupelo), but thousands of decrepit,overmature cypress and tupelo still exist,including small parcels of uncut centuries-oldforest in the Dagmar Wildlife ManagementArea and the Cache River National WildlifeRefuge, located near Brinkley. The BayouDeView woodlands are representative of other

Decadal Drought Effects onEndangered Woodpecker Habitat

BYD. W. STAHLE, M. K. CLEAVELAND, R. D. GRIFFIN,M. D. SPOND, F. K. FYE, R. B. CULPEPPER,ANDD. PATTON

PAGES 121, 125

Fig. 1. An ancient bald cypress tree in the800-year age class at Bayou DeView, Ark.,the rediscovery site of the ivory-billed wood-

pecker (diameter 2.6 meters at 2 meters above

ground). David Stahle pictured for scale. Photoby Mark Spond.


6/10

Eos, Vol. 87, No. 12, 21 March 2006

Fig. 2. (a) Mean ring-width chronologies for Bayou DeView, Black Swamp, and Mayberry Sloughare plotted without detrending for the past 850 years. (b) The standardized r ing-width chronol-ogy of bald cypress for the Western Lowlands is based on these three sites and documents severe

sustained drought in the fourteenth, fifteenth, and sixteenth centuries (shaded red). The samplesize profile (dashed curve indicates living trees, solid curve indicates trees and logs) suggests asurvivorship effect and a subsequent recruitment event for cypress-tupelo forests in the WesternLowlands during the fourteenth- and fifteenth-century droughts (arrows). (c) The spatial patternof tree-ring reconstructed Palmer Drought Severity Indices for North America during these epicdroughts is based on Cook et al.[2004].


7/10

Eos, Vol. 87, No. 12, 21 March 2006

selectively logged or uncut noncommercialcypress-tupelo stands still scattered sparinglyacross the southeastern United States.

Black River, N.C., is a premier example ofnoncommercial ancient cypress, dominatedby smaller cypress trees too shaky, pecky, andheart-rotten to justify logging. The Black Riversite today contains the oldest-known livingtrees in the eastern United States, includingone tree at least 1700 years old and several

partly hollow trees likely over 2000 years old[Stahle et al., 1988]. Noncommercial cypresstimber was often found in acidic, nutrient-poor blackwater streams like the Black River,and in deeper water along bayous wheresmaller, heavily buttressed, and branchingtrees were common.

This environmental gradient in the formand size of cypress trees across virgin south-ern floodplains was discussed byDickesonand Brown[1848] and illustrated byMat-toon[1915]. Mattoons intricate drawingshighlight the uneven distribution of bothvaluable and noncommercial cypress acrossthe subtle topographic and hydrologic gra-

dients of southern floodplains and swamps(Figure 3).These two important historical sources pro-

vide a clear predictive model for where in thecomplex, highly altered southern floodplainsold-growth bald cypresstupelo remnantscan still be found in noncommercial set-tings, proven in part by dendrochronologicaldiscoveries of centuries-old cypress at BayouDeView, Black River, Choctawhatchee River(Fla.), Pascagoula (Miss.), and elsewhere (e.g.,http://www.uark.edu/dendro/oldgrowth).

How much old-growth cypress-tupelo foreststill remains in noncommercial timberlandsof the southeastern United States and howthey might be integrated into conservationand restoration efforts is not known. However,the discovery of at least one surviving popula-tion of ivory bills proves the habitat value ofeven the decrepit overmature cypress-tupelostands such as Bayou DeView and addsurgency to the identification and protectionof other ancient swamp forests throughout thebottomlands of the South.

Acknowledgments

This research was supported by the U.S.National Science Foundation (grant ATM-0400713), and facilitated by the ArkansasGame and Fish Commission.

References

Cook, E. R., C. A. Woodhouse, C. M. Eakin, D. M. Meko,and D. W. Stahle (2004), Long-term aridity changesin the western United States,Science,306,10151018.

Dickeson, M. W., and A. Brown (1848), On the cypresstimber of Mississippi and Louisiana,Am. J. Sci. Arts,5(13), 515522.

Fitzpatrick, J. W., et al. (2005), Ivory-billed woodpecker(Campephilus principalis) persists in continentalNorth America,Science, 308, 14601462.

Mattoon, W. R. (1915), The Southern Cypress,Bull. 272,74 pp., U.S. Dep. of Agric., Washington, D.C.

Shugart, H.H. (2004), How the Earthquake BirdGot Its Name and Other Tales of an UnbalancedNature, 288 p., Yale University Press, New Haven.

Stahle, D. W., and M. K. Cleaveland (1992), Recon-struction and analysis of spring rainfall over the

southeastern U.S. for the past 1000 years,Bull. Am.Meteorol. Soc., 73, 19471961.

Stahle, D. W., M. K. Cleaveland, and J. G. Hehr (1988),North Carolina climate changes reconstructedfrom tree rings: A.D. 3721985, Science, 240,15171519.

Tanner, J. T. (1942), The Ivory-Billed Woodpecker,111 pp., Natl. Audubon Soc., New York.

Author Information

David W. Stahle, Malcolm K. Cleaveland, R. Daniel

Griffin, Mark D. Spond, and Falko K. Fye, Tree-Ring

Laboratory, Department of Geosciences, University of

Arkansas, Fayetteville: E-mail: [email protected]; R.

Brian Culpepper, Center for Advanced Spatial Tech-

nologies, University of Arkansas, Fayetteville; and

David Patton, Ancient Cross Timbers Consortium,

Checotah, Okla.

Fig. 3. These drawings illustrate the variable age structure and timber value typically found in vir-gin cypress swamps (redrawn from Mattoon[1915]) and provide a conceptual model for whereold-growth noncommercial cypress-tupelo woodlands can still be found in the southeastern Unit-ed States. (a) The transect across Okeefenokee Swamp, Ga., illustrates young cypress surroundingopen water, moving outward to a pure stand of large cypress, and then to the oldest edges of the

swamp where overmature cypress and mixed hardwoods were typically encountered, a vegeta-tion chronosequence reflecting the increasing age and infilling of the swamp. The pure stands oflarge cypress were heavily logged across the South, but the stands of decrepit overmature cypresswere sometimes left uncut and a few survive today as core habitat for obligate old-growth spe-cies. (b) Mattoons cross section of a typical southern floodplain also illustrates the deep cypress

swamp where large commercial timber was often found and was heavily cut. Stunted, poorlyformed noncommercial timber was typical of deeper cypress sloughs, where ancient trees can

sometimes still be found lining these picturesque southern bayous.


8/10

Eos, Vol. 87, No. 12, 21 March 2006

Minerals created under high temperature

conditions have been found in particles col-lected from the comet Wild 2 and may havecome from the formation of the Sun oranother solar system, NASA mission scien-tists said at a 13 March press conference.

The Stardust spacecraft trapped the parti-cles in an aerogel detector when it passedwithin 240 kilometers of the comet on 2 Jan-uary 2004. Mission scientists have been pro-cessing the tiny grains, which range in sizefrom 50 microns to less than one micron,since a few days after the Stardust returncapsule landed in the Utah desert on 15 Jan-uary 2006.

Stardust principal investigator Donald

Brownlee, from the University of Washington,

Seattle, said, The interesting thing is we arefinding these high-temperature minerals inmaterials from the coldest place in the solar

system. The minerals, which include peridot,olivine, and titanium nitride, formed at tem-peratures above 1400 K, whereas the cometitself formed at about 30 K.

Michael Zolensky, Stardust curator and co-investigator at NASAs Johnson Space Centerin Houston, Tex., suggested that if the high-temperature minerals originated from theSun, they could have been ejected and car-ried out to the edge of the solar system onsome sor t of conveyor belt.

Stardust scientists are still determininghow best to handle these small samples, andso far only six of the 132 cells in the aerogeltray have been processed. Zolensky said that

more than 150 samplespieces of particles

recovered from the aerogelhad been pro-vided to scientists on five continents. Afterthis processing phase concludes in the nextseveral months, qualified scientists anywherein the world will be able to request samplesfor analysis.

A second aerogel detector on Stardustcollected samples of interstellar dust, parti-cles much smaller than those collected fromthe comet. After a detailed scan of the tray

and its samples, which should start in abouta month, the images will be sent to partici-pants in the Stardust at Home project. Usinga virtual microscope, project participantswill search these images for evidence ofinterstellar dust impacts.

Information about Stardust is available athttp://stardust.jpl.nasa.gov, and details aboutStardust at Home is available at http://stardustathome.ssl.berkeley.edu/

SARAHZIELINSKI, Staff Writer

Fire-Made Minerals Found in Icy Comet

3456

PAGE 122

A newly developed advanced research air-craft will allow researchers to directly studythe atmosphere for extended periods of timeat altitudes that approach the troposphere-stratosphere boundary.

The plane, called the High-performance

Instrumented Airborne Platform for Environ-mental Research (HIAPER), can carry nearly3000 kilograms of scientific instrumentation,reach an altitude of more than 15,500 meters,and cruise without refueling for over 11,200kilometers. Owned by the U.S. National Sci-ence Foundation (NSF) and operated by theNational Center for Atmospheric Research(NCAR) in Boulder, Colo., HIAPER will beused to collect detailed information on the

meteorology of the upper edges of hurricanesand thunderstorms, high-altitude chemicalreactions that are believed to affect climate,and other research concerns.

HIAPER embarked on its first science mis-sion on 2 March to study atmospheric whirl-winds called rotors, which form on the leeside of steep mountains and have contributedto several aircraft accidents. Through April,HIAPER is flying over rotors near CaliforniasSierra Nevada range, as part of a projectnamed the Terrain-Induced Rotor Experiment(T-REX).

The current science campaign could nothave been done without the long-range capa-bilities of such an aircraft, explained Marga-ret Leinen, assistant director for geosciencesat NSF. HIAPERs ability to reach high altitudes

will allow researchers to observe rotors fromabove and release surveying instruments intothe most turbulent areas.

Leinen added that HIAPERs communica-tions and data capabilities will allow theentire T-REX science team to participate inthe experiment. Other researchers stationedon the ground are probing rotors thoughobserving techniques including radar, lidar,and wind profilers.

With our advanced instrument payloadand our flight paths, the amount of data we

will collect will be unprecedented fordescribing airflow over mountains, saidT-REX scientist Jorgen Jensen of NCAR.

For more information, visit the Web site:http://www.haiper.ucar.edu

MOHIKUMAR, Staff Writer

Research Aircraft Helps ScientistsStudy Troposphere

PAGE 122


9/10

Eos, Vol. 87, No. 12, 21 March 2006

Efforts over the past several decadestoward increasing the number of womenentering science and engineering fieldshave largely been successful, with under-graduate and graduate school enrollmentsaveraging between 30 and 50 percentwomen (see Nelson Diversity Survey, http://cheminfo.chem.ou.edu/faculty/djn/diversity/top50.html). Ph.D. attainments show similarprogress. However, the percentage ofwomen occupying tenure-track positionshas not risen commensurably. Across theboard, women in science and engineeringfill on average only 15 to 25 percent of aca-

demic positions.Since the number of women in graduate

school has been sufficiently large for at leasta decade, it is difficult to ascribe the lowerpercentage of women in faculty positions toa small pool of potential candidates. Asreported in the Chronicle of Higher Education(3 December 2004), the disparity between thenumber of women trained in a field and thenumber of women occupying positions inthat field is instead attributed by some to sub-tle biases that keep women out of research oracademic positions; others, according to thereport, argue that women are simply stayingaway of their own accord from these positions.

Though the possibility of the first attribu-tion cannot be discounted, the focus of acommunity mentoring effort initiated withinthe physical oceanographic community ison the latter attribution, namely, that womenare opting out of the pipeline in the early

years of their scientific careers. Thus, whilerecruitment efforts should be lauded, thecommunity also needs to turn its attentionto retention to capitalize on the investmentthat funding agencies and universities havemade on the education of women studentsand to create a scientific workforce whosediversity matches that of the student popula-tion and more closely mirrors that of the

U.S. population as a whole.Ocean sciences provide no exception tothese trends. For example, the number ofwomen receiving their Ph.D. in physicaloceanography has approached 40 percent atmost major oceanographic institutions; how-ever, the number of women with principalinvestigator (PI) status remains fairly low.Though not a direct accounting of the num-ber of women in the field, it is interesting tonote that in the past 10 years, only 12 per-cent of all proposals submitted to the physi-cal oceanography program at the U.S.National Science Foundation (NSF) havehad women as the lead PI.

It is important to recognize that in thefield of oceanography, a sizeable fraction ofwomen, as well as men, are employed in non-academic positions. Though the recentnational diversity study cited above focusedon academic positions, and the statistic fromNSF primarily sheds light on the retentionissue in academia and research institutions,the community mentoring effort concernswomen employed in the myriad places thatoceanographers apply their skill: governmentlabs, consulting firms, universities, researchinstitutions, and so forth. One of the goals ofthis effort is to gather firm statistics on theretention of women in the field in order toassess, among other things, whether these

workplaces differ in the hiring and retentionof women oceanographers.

MPOWIR Workshop

There are many factors that contributeto the lack of retention of women scientists:competition between family building andcareer building, competition between thecareer goals of a spouse/partner, lack offemale role models, lack of adequate mentor-ing, and so forth. While some of these prob-lems are best met with institutional changes,the lack of adequate mentoring is one thephysical oceanographic community can

address. Toward this end, an NSF- and U.S.Office of Naval Research-funded workshop,called Mentoring Physical OceanographyWomen to Increase Retention (MPOWIR),recently was conducted on this topic.

Twenty-nine physical oceanographers,men as well as women, from a spectrum ofworkplaces, assembled at the workshop todesign a mentoring program for juniorwomen in the field of physical oceanogra-phy to help remove barriers, real or per-ceived, in their career development. Theoverall goal of this community mentoringeffort is to develop a program within thephysical oceanographic community essen-

tially as a pilot project that, if successful,could be expanded to include women inall areas of ocean sciences, or geosciences,at a later date. Additionally, efforts towardretaining women in the field could betransferable to the retention of minori ties, agoal endorsed by the MPOWIR steeringcommittee.

The initial goal of the workshop was toidentify the obstacles that junior womenface in their career development and todetermine which of those obstacles couldbe met by a community effort rather than byinstitutional efforts. Toward this end, work-shop participants learned of institutional

efforts facilitated by NSFs ADVANCE programand of local mentoring programs, such asone recently implemented at the WoodsHole Oceanographic Institution in Massa-chusetts. Results from a survey available onthe MPOWIR Web site (http://www.mpowir.org) prior to the workshop also provided keybackground information.

In addition, participants read of mentor-ing efforts in other disciplines; however,they recognized that the physical oceanog-raphy community cannot simply adopt aprogram that has been developed foranother discipline. A career in oceanogra-phy is unique in that it often requires seatime; there are few, if any, industry jobs; thenumber of geographical locations whereoceanography jobs are available is limited;there are a relatively large proportion ofresearch positions versus academic posi-tions; and the field is relatively small com-pared with computing sciences, mathematics,physics, and so forth.

From workshop discussions, backgroundreadings, presentations, and survey results, itwas concluded that the transitions from Ph.

D. to postdoctoral student and then frompostdoc to entry-level position were themost vulnerable times for a junior womanin the field. Obstacles identified includeexclusion from large research programs;lack of collaboration and collaborators;lack of senior women role models; and lackof advice on career development and onbalancing family and work. Importantly, thesurvey results showed that only 30 percentof the respondents had formed an impor-tant mentoring relationship during theirpostdoctoral years.

Given the identified obstacles and theknown importance of mentoring, MPOWIR

workshop participants decided to design acommunity-mentoring program that wouldprovide continuity from the Ph.D. attainmentthrough the early years of a young womanscareer. Workshop participants decided tofocus on the collective community respon-sibility for mentoring rather than on men-toring that matched a single junior scientistwith a single senior scientist. The groupsgoal is to create a network of mentors thatcan fulfill the various needs of a junior scientist.

Because the goal is to make mentoringaccessible to junior women in a wide varietyof positions and at different types of work-places (e.g., research institutions, government

labs, and universities), the implementation ofthe program is multi-pronged. From themeetings deliberations, three main elementsfor a community-mentoring program emerged:

1. An Internet-based mentoring programistobe composed of four components: (a) amoderated, anonymous community forum toaddress issues related to the success ofjunior women in physical oceanography, butaccessible to the entire community; (b) asearchable database for mentors to be usedas a resource for junior women; (c) a list-server with important information availableto interested scientists about mentoring andfunding activities; and (d) a resource library

Mentoring Program for Womenin Physical Oceanography

PAGES 123, 126

,!!&+)-#


10/10

Eos, Vol. 87, No. 12, 21 March 2006

on mentoring issues, data and statistics, andlinks to funding opportunities.

2. The centerpiece of the MPOWIR pro-posed program, an annual Pattullo confer-ence, would provide an opportunity for alljunior women in the field to talk to seniorscientists about their current and plannedwork. The goal is for senior scientists, menand women, to provide feedback, giveadvice, and make connections for these

young women. The conference would alsoinclude round-table discussions on careerdevelopment issues. (In 1957, June GracePattullo was the first woman to receive aPh.D. in physical oceanography from theScripps Institution of Oceanography, andshe is believed to be the first to receivesuch a degree in the United States.)

3. AGU social gatherings on mentoringwould take place at all Ocean Sciencesmeetings and at the AGU Fall Meeting inalternate years. The goal of these socialswould be to facilitate connections between

junior scientists and more senior scientistsin the field. Talks and/or panel discussionson career and mentoring issues are alsoplanned. As part of this plan, a town hallmeeting was recently held at the Ocean Sci-ences 2006 meeting in Honolulu, Hawaii forthe express purpose of providing the com-munity with information about MPOWIR.Over 150 people attended the meeting andreception.

In order to implement these initiativesand to measure their success, workshop par-ticipants decided to establish an ongoingcommittee that would take responsibility forthe implementation of the proposed pro-gram elements, establish mechanisms toidentify mentees and attract mentors, andcreate a statistical database in order toquantify success. This committee has sincebeen established and is in the process ofsecuring funds to implement the above pro-gram elements.

The physical oceanographic communitycannot change the structure of family lifenor can it make major organizationalchanges to the structure of scientificcareers; however, it can begin to make a dif-ference in the mentoring of women juniorscientists. If successful, the MPOWIR com-munity-run program will aid capitalizationon the investment the funding agencies anduniversities have made on the education of

women, and it will help create a morediverse scientific workforce. Additionally, itis believed that by creating a scientificcommunity that facilitates the retention ofwomen, a community will be created that ismore attractive to minorities as well.

The MPOWIR workshop was held 912October 2005 at the Airlie Center in Warren-ton, Va.

M. SUSANLOZIER, Earth and Ocean Sciences,Duke University, Durham, N.C.; E-Mail: mslozier@

duke.edu

2729 March 2006 External Controls onDeep Water Depositional Systems, Piccadilly,London, U.K. Sponsors: Geological Society of Lon-don; Society for Sedimentary Geology. (A. Johnson,The Geological Society, Burlington House, Picca-dilly, London, U.K. W1J 0BG; Tel.: +011-44-020-7434-9944; Fax: +011-44-020-7434-0579; E-mail: [email protected]; Web Site: http://www.geolsoc.org.uk/deepwater)

Conference topics include links between cli-

mate and sea level, fluvial erosion and transport,paleoclimate modeling, ancient climate controls,and ancient shelf-edge systems.

1820 April 2006 Guiding National OceanResearch Investment: Public Workshop onthe Ocean Research Priorities Plan, Denver,Colo., USA. Sponsor: National Science and Technol-ogy Council Joint Subcommittee on Ocean Sci-ence and Technology. (S. Walker, USGCRP/CCSPOffice, 1717 Pennsylvania Avenue, Suite 250, Wash-ington, D.C., USA 20006; Tel.: +1-202-419-3464; Fax:+1-202-223-3064; E-mail: [email protected]; WebSite: http: //ocean.ceq.gov/about/jsost_workshop/welcome.html)

The workshop will focus on key aspects of theOcean Research Priorities Plan. Themes includethe oceans roles in climate variability and change,marine transportation and security, ocean educa-

tion, and ocean observations and technology. Theworkshop will allow participants to address com-

mon research needs and provide input on theestablishment of national ocean researchpriorities. 2627 April 2006 National Commission onScience for Sustainable Forestry Forest Dis-turbance, Management and Biodiversity Sym-posium, Denver, Colo., USA. Sponsors: National For-est Foundation; Surdna Foundation; The David andLucile Packard Foundation; others. (A. Lien,National Council for Science and the Environment,1707 H Street NW, Suite 200, Washington,D.C., USA 20006; Tel.: +1-202-530-5810; Fax: +1-202-628-4311; E-mail: [email protected]; Web Site: http://www.ncseonline.org/NCSSF)

The symposium will bring together a diversegroup of scientists, decision makers, and forestusers to learn about current research and issues inthe area of forest disturbance. Topics include theeffects of invasive species, insect outbreaks, andfires on biodiversity.

1921 June 2006 Academic Science and ItsRole in the Development of the ProductiveForces in the Northern Regions of Russia,Arkhangelsk, Russia. Sponsors: Russian Academy ofScience; Council for Research Productive Forces ofthe Administration of Arkhangelsk.(Y. Borovaya, Arkhangelsk Scientific Centre, RussianAcademy of Science, ul. Sadovaya 3, Archangel,Russia 163000; Tel.: +011-007-8182-215765;E-mail: [email protected])

The conference is dedicated to the centennial

anniversary of the opening of the first station ofthe Russian Academy of Science. Topics include

the development of oil and gas fields, research onshelf seas and continental reservoirs, and problemsin biodiversity and the conditions of ecosystemsin the northern regions of Russia.

27 July 2006XII International Symposiumon Vulcanospeleology, Tepoztlan, Morelos, Mex-ico. Sponsors: International Union of Speleology;Mexican Society for Underground Exploration;Association for Mexican Cave Studies; others.(R. Espinasa; E-mail: [email protected];Web Site: http://www.saudicaves.com/symp06/index.html)

The symposium will include presentations onlava caves as well as three days of field trips toIglesia Cave. There will be post-symposium fieldtrips to the longest lava tube in the Americas andto the lava tubes of El Volcancillo Veracruz, whichbegin from a crater more than 100 meters deep.Abstract deadline is 31 March.

1621 July 2006 7th International Confer-ence on the Occurrence, Properties, andUtilization of Natural Zeolites, Socorro, N.M.,USA. Sponsors: International Natural ZeoliteAssociation; Biolite, Inc.; GSA Resources, Inc.;others. (R. Bowman, New Mexico Tech, Depart-ment of Earth and Environmental Science, 801Leroy Place, Socorro, N.M., USA 87801; Tel.: +1-505-835-5992; Fax: +1-505-835-6436; E-mail:[email protected]; Web Site: http://www.ees.nmt.edu/Zeolite06)

Meeting topics will include zeolite formationand occurrence, mineralogy of natural zeolites,zeolites in radioactive waste control, and the envi-ronmental applications of zeolites. There will alsobe a mid-week excursion and a post-meeting field

trip to zeolite localities in the southwestern U.S.Abstract deadline is 1 April.

PAGE 122

M E E T I N GA N N O U N C E M E N T S

eos_leyte_landlside_2006.pdf

Documents

Transcript of eos_leyte_landlside_2006.pdf