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-8A/8B

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

Site SUMA-10A

Stratigraphy

• 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