Overview of NanTroSEIZE: The Nankai Trough Seismogenic Zone Experiment Harold Tobin University of...
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Transcript of Overview of NanTroSEIZE: The Nankai Trough Seismogenic Zone Experiment Harold Tobin University of...
Overview of NanTroSEIZE:The Nankai Trough Seismogenic
Zone Experiment
Overview of NanTroSEIZE:The Nankai Trough Seismogenic
Zone Experiment
Harold TobinUniversity of Wisconsin – Madison
Masataka KinoshitaJAMSTEC - IFREECo-Chief Project Scientists & Expedition 314 co-Chiefs
for NanTroSEIZE Proponents, Project Management Team, and Expedition 314 – 316 Scientists
NanTroSEIZE transect spans NanTroSEIZE transect spans the up-dip limit of the M8+ the up-dip limit of the M8+ seismogenic asperity seismogenic asperity
3D seismic& drilling transect3D seismic& drilling transect
1944
1946
Inferred Asperity of1944 Tonankai earthquake
(Ichinose et al., 2003)
(Baba and Cummins, 2005)
(Kikuchi and Yamanaka, 2001)
NanTroSEIZE targets an up-dip maximum of large slip in 1944 and the presumed locked portion of the plate interface today
NanTroSEIZE objectives:NanTroSEIZE objectives:Building a Building a distributed observatorydistributed observatory spanning spanning the up-dip end of the interplate seismogenic the up-dip end of the interplate seismogenic
zonezone
~8 planned drilling sites, to depths from ~300 to ~6000+ m ~8 planned drilling sites, to depths from ~300 to ~6000+ m
below the seafloorbelow the seafloor
Core sampling, logging, downhole testing, and long-term Core sampling, logging, downhole testing, and long-term
monitoring – all to provide data on monitoring – all to provide data on fault physics fault physics at several at several
locations in P, T, and structural/diagenetic evolutionlocations in P, T, and structural/diagenetic evolution
Objectives of NanTroSEIZE Document the material properties and state of the plate boundary fault
system at several P-T and lithology conditions, testing hypotheses for stable
vs. unstable frictional behavior.
Investigate partitioning between seismic vs. aseismic processes on the main
plate boundary, through monitoring of seismicity, borehole strain, pore fluid
pressure, and temperature.
Test whether there are interseismic temporal changes in state – including
possible earthquake precursory signals.
Calibrate observations in the broader geophysical volume (3D seismic)
surrounding the boreholes to the rock properties and state.
NanTroSEIZE is primarily about FAULT MECHANICS
NanTroSEIZE:Background on project
organization
NanTroSEIZE:Background on project
organizationSet of IODP Drilling Proposals submitted and reviewed from 2001 - 2004
IODP’s first “Complex Drilling Project” (CDP) designation and first “Project Management Team” (PMT) set up to implement
3D MCS survey funded as Site Survey by NSF-ODP (~25%) and MEXT (~75%), acquired in 2006U
.S. P.I.s: G. Moore, N. Bangs, H. Tobin, S. Gulick, D. Saffer)
Drilling of Stage 1 from Sept 2007 - Feb 2008
Set of IODP Drilling Proposals submitted and reviewed from 2001 - 2004
IODP’s first “Complex Drilling Project” (CDP) designation and first “Project Management Team” (PMT) set up to implement
3D MCS survey funded as Site Survey by NSF-ODP (~25%) and MEXT (~75%), acquired in 2006U
.S. P.I.s: G. Moore, N. Bangs, H. Tobin, S. Gulick, D. Saffer)
Drilling of Stage 1 from Sept 2007 - Feb 2008
3D seismic box
Mega-Splay Fault
Oceanic Crust Decollement
Nankai accretionary wedge3D imaging by pre-stack depth migration
Stages OverviewStages Overview Stage 1 – 2007-2008
Riserless drilling of 8 sites up to ~1400 m depth.
Stage 2 – Planned for 2009 First riser-based deep site drilling at NT2-11 to ~3000 m.
Additional riserless operations at Inputs sites and riserless observatories (“CORKs”)
Stage 3 – Planned for 2011-2012 ?? ~6000 m riser site drilling C0002 (NT3-01) Observatory installation efforts at other sites.
Stage 4 - Long-term monitoring system completion in 2 deep riser boreholes.
Stage 1 – 2007-2008 Riserless drilling of 8 sites up to ~1400 m depth.
Stage 2 – Planned for 2009 First riser-based deep site drilling at NT2-11 to ~3000 m.
Additional riserless operations at Inputs sites and riserless observatories (“CORKs”)
Stage 3 – Planned for 2011-2012 ?? ~6000 m riser site drilling C0002 (NT3-01) Observatory installation efforts at other sites.
Stage 4 - Long-term monitoring system completion in 2 deep riser boreholes.
Chikyu gets underwaySeptember, 2007
First expeditions on Chikyu
71 scientists from 12 countries were onboard for 5 months of continuous operations (Sept 21, 2007 – Feb 5, 2008)
Drilled 33 holes at 8 sites up to 1400 meters below the sea floor
Obtained core samples from active faults and environment
Found major variations in stress orientations, providing evidence for location of the up-dip limit of frictionally locked plate interface
Future plan to drill up to 6000+ meters depth to sample and instrument in and around the seismogenic zone
First expeditions on Chikyu
71 scientists from 12 countries were onboard for 5 months of continuous operations (Sept 21, 2007 – Feb 5, 2008)
Drilled 33 holes at 8 sites up to 1400 meters below the sea floor
Obtained core samples from active faults and environment
Found major variations in stress orientations, providing evidence for location of the up-dip limit of frictionally locked plate interface
Future plan to drill up to 6000+ meters depth to sample and instrument in and around the seismogenic zone
NanTroSEIZE Stage 1:NanTroSEIZE Stage 1:Expeditions 314, 315, and 316Expeditions 314, 315, and 316
Stage 1 drilling on interpreted arbitrary line from 3D seismicStage 1 drilling on interpreted arbitrary line from 3D seismic
Interp. by G. Moore, 2008
NanTroSEIZE Future PlansNanTroSEIZE Future Plans2009: IODP Expeditions 319, 322, 323
Drill and prepare to install seismic / geodetic / hydrologic observatories at 3 sites above seismogenic zone
Core the subduction inputs to basement
2009: IODP Expeditions 319, 322, 323
Drill and prepare to install seismic / geodetic / hydrologic observatories at 3 sites above seismogenic zone
Core the subduction inputs to basement
NanTroSEIZE Future PlansNanTroSEIZE Future Plans2011 Install monitoring systems in cased boreholes:
Seismometer array, Strainmeter, tiltmeter, pore pressure, and temperature
2012 until 20?? Drill with riser system to megasplay fault/plate boundary at
C0002, or equivalent site.
2011 Install monitoring systems in cased boreholes:
Seismometer array, Strainmeter, tiltmeter, pore pressure, and temperature
2012 until 20?? Drill with riser system to megasplay fault/plate boundary at
C0002, or equivalent site.
Link to cabled observatory network for real-time monitoring
Japanese seafloor cabled network DONET will be completed in 2010
NanTroSEIZE IODP borehole observatories will be connected
What has changed since project conception?What has changed since project conception?
Where does the plate boundary lie beneath the forearc basin and mega-splay?
What has changed since the project conception?What has changed since the project conception?
2009 ExpeditionsCall for Participants out now!2009 ExpeditionsCall for Participants out now!
www.iodp.orgwww.iodp.org
NT2-11 Observatory option 1:TD=2500m bsf
BBseismometer is installed at ~1600m to avoid high temperature3 tiltmeters are installed within 9-5/8” section in the accretionary prismPP at the bottom, plus ~1600m (perforated and packer-sealed)