iodp exp 362 sumatra seismogenesis 012115
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Iodp Exp 362 Sumatra Seismogenesis 012115TRANSCRIPT
IODP Expedition 362:Sumatra Seismogenesis
Co-Chief ScientistsLisa McNeill (Southampton)Brandon Dugan (Rice)
Staff ScientistKaterina Petronotis (JRSO)
July 31 –September 30, 2016
Proposal ProponentsLisa McNeill (University of Southampton, UK)Sean Gulick (University of Texas, Austin, US)James Austin (University of Texas, Austin, US)Nathan Bangs (University of Texas, Austin, US)Timothy Henstock (Univ. of Southampton, UK)Chris Goldfinger (Oregon State University, US)Don Fisher (Penn State University, US)Brandon Dugan (Rice University, US)Julia Morgan (Rice University, US)Kitty Milliken (University of Texas, Austin, US)Glenn Spinelli (New Mexico Tech, US)Peter Clift (Louisiana State University, US)Ellen Thomas (Yale University, US)Kevin Pickering (University College London, UK)Kelin Wang (Pacific Geoscience Centre, Canada)U. Udrekh (BPPT, Indonesia)Haryadi Permana (LIPI, Indonesia)Grant Garven (Tufts University, US)Maria Ask (Lulea University, Sweden)Dieter Franke (BGR, Germany)Kai Berglar (BGR, Germany)
Heidrun Kopp (Geomar, Germany)Yusuf Djajadihardja (BPPT, Indonesia)Satish Singh (IPGP, France)Jean Claude Sibuet (IFREMER, France)Stefan Ladage (BGR, Germany)Christof Gaedicke (BGR, Germany)Frauke Klingelhoefer (IFREMER, France)D.H. Natawidjaja (LIPI, Indonesia)David Mosher (GSC, Canada)Kerry Sieh (NTU, Singapore)Wonn Soh (JAMSTEC, Japan)Jacob Geersen (Univ. of Southampton, UK)Nicolas Chamot-Rooke (ENS-CNRS, France)David Tappin (British Geological Survey, UK)
Background
• Subduction zone inputs help control fault properties, including
frictional properties, fluid production, and permeability (e.g.,
Underwood, 2009)
• Past drilling targeted inputs at erosional and accretionary
margins, e.g., Nankai, Cascadia, Barbados, Costa Rica
• In the last decade:
– A series of M≥9.0 earthquakes, the first since 1964 (seismological and
structural resolution many orders of magnitude greater than 1960’s)
– Breadth of fault slip phenomena has exploded and with it new theories
on how faults slip
• Recent and future ocean drilling expeditions target margins with
unexpected slip behaviour (shallow slip, non-earthquake slip)
and explore a wider range of inputs
1) Establish initial and evolving properties of the North Sumatran incoming sedimentary section
2) Constrain potential effects on seismogenesis, tsunamigenesis,and forearc development for comparison with global examples
Primary Objectives
1) Core and log the complete input stratigraphic sequence to derive primary stratigraphic, lithological, hydrogeological, chemical, physical, thermal, biological, and structural properties
2) Assess diagenetic alteration of sequence and how diagenetic processes will evolve with increasing burial and heating, and ultimately on accretion
Approach
Geersen et al., 2013
Sediment strengthening, thick input section
Smith, et al., 2013
Thermal modeling suggests temperatures of ~150°C at the
top of oceanic basement at the deformation front
The décollement sits at blue line, T ~100-125°C
1. Makran
2. North Sumatra
Sunda margin (Sumatra) 2004 Mw 9.2 earthquake
Chlieh et al., 2007
Rhie et al.,
2007
Fuji and Satake, 2007
• First Mw ≥ 9.0 earthquake since 1964
• Coseismic slip models indicate significant slip and moment release further seaward than expected
• Several models suggest slip close to the trench
geodetic seismic + geodetictsunami
Sunda margin,
eastern Indian Ocean
McNeill and Henstock, 2014, Tectonics
Thick sediment input
Dominated by Bengal-Nicobar submarine fan sediments
No previous drilling at this margin
Evolution of Sumatra Proposal
2007 Objectives
Prism evolution
Link seismogenic zone and prism structure
Forearc basin evolution
S-CORK monitoring post earthquake
2010 Objectives
Forearc plateaudevelopment
Forearc basin development
Links between forearc structure and seismogenic zone position and rupture process
Evolution of Sumatra Proposal
April 2013 Objectives
Input material properties (influence on plate boundary fault behavior and forearc structure)
Models for forearc plateau uplift and evolution
Submarine paleoseismology
Evolution of Sumatra Proposal
October 2013 Objectives
Properties and evolution of the input sediment section
Effects of evolving input section on plate boundary fault properties and forearc structural development
Nicobar fan history
Evolution of Sumatra Proposal
Proposed Drilling
Unit 1: Rapidly deposited trench wedge 0 - ~4 Ma ~0.1 - 3 km thickUnit 2: Bengal-Nicobar fan sediments ~4 - ~40 Ma ~1.0 km thickUnit 3: Pre-fan pelagic sediments ~40 - ~65 Ma ~0.4 - 1.0 km thick
Plate boundary fault (décollement) position and development:Two candidates: - Prominent lithological reflector within Unit 3 (Dean et al., 2010) at ~3.5-4.5 km- Reflector within lower Unit 2 (Cook et al., 2014) at ~3-4 km
Site SUMA-8A/8B
Core and log lower section of input sediments on the Indian oceanic plate (Nicobar Fan) to 1760 mbsf (water depth 4130 m)
Penetrates hypothesized pre-decollement section
Stress state in sedimentary section and oceanic basin
Site SUMA-10A
Core and log trench wedge infill and uppermost slowly deposited submarine Nicobar fan and hemipelagic materials to 1400 mbsf(water depth 4490m)
Penetrates trench wedge unconformity
Stress state in sedimentary section
• Décollement typically forms near the base of incoming sediments
• Composition: clays (e.g., smectite/illite), opal content, calcareous ooze, diatomaceous sediments, and non-pelagic/hemipelagic sequences play a role
• Hydrology: pore pressure, diagenetic fluid sources, compaction, permeability
• Thermal state of oceanic basement
• Degree of compaction or diagenetic alteration pre-subduction
Leg 190 Site 1173 Nankai-Muroto, Japan input
section, from Underwood, 2007
Importance of Inputs
• In situ temperature and pore pressure measurements
• Post-cruise experimental and numerical analyses – evolution of hydrology and
mechanical-frictional behaviour
– impacts of increased P/T as the input thickens, accretes and the plate boundary fault develops
• Does the shallowest section of allow coseismic/earthquake slip, as observed– What are the primary
controlling factors?
Expedition 362 – Beyond Coring & Logging
Exp 308
Long et al., 2008
Saffer & Tobin, 2011