IFREE JAMSTEC Shuichi Kodaira   The 2011 Tohoku-oki  Deep sea observations of slip to the trench axis  On-going and future projects

 Nankai Trough  NanTroSEIZE  DONET  On-going and future projects Strong grand motion Teleseismic Tsunami

Yoshida et al. 2011 Lay et al. 2011 Fujii et al. 2011

- may indicate a need to revise the widely accepted conceptual model of a seismogenic zone

- however, these observations alone could not identify an exact up-dip limit of the coseismic displacement

Benchmark displacement obtained by acoustic ranging ItoIto et et al., al. 20112011

We still did not know the up-dip end of the slip

Sato et al., 2011 Kido et al., 2011 Fujiwara et al (2011)

10m 50m

LargeCo horizontal-seismic displacement displacement near reaching trench is ato cause the oftrench the large axis tsunami Normal Frontal prism Trench axis North American plate Reflective zone

(Kodiara et al., in review)

We still do not know where and how coseismic displacement extent to the trench axis Where is a surface break ? 1999 Before Earthquake 2011 After Earthquake (Kodiara et al., in review)

Co-seismic rupture reached at the trench axis associated with deformation of the trench filled sediment 2011 After Earthquake Coring sites

Record of a slip-to-the-toe event may be preserved in trench-fill sediment Just after EQ Before EQ Upward fining units

Figure courtesy of Toshiya Kanamatsu, IFREE

Upward fining units indicating turbidite triggered by the 2011 earthquake Similar lithology at1.8m below surface = Previous event ?

PC03 sec. 1-5

Figure courtesy of Toshiya Kanamatsu, IFREE ~900 m drilling to the fault zone at 7000 m deep Temperature monitoring, coring and logging

50 m N. American plate  2012-2017  High resolution seismic along the trench axis  Large scale active-source seismic imaging  High resolution bathymetry mapping 2012-15  Coring at the trench axis and forearc basin  Earthquake-geodetic observation, incl. BBOBS

and OBP ‘11 ‘14 ‘12 ‘15 ‘13

 Plan to deploy by 2015

 Japan Trench – S. Kuril trench, incl. outer rise

 Seismometer and

pressure sensor Chiba Ibaraki-Fukushima Miyagi-Iwate Aomori-Hidaka Tokachi-Kushiro Outer rise Existing cable

M7 after 1923 Kanazawa 2012  Japan Trench  The 2011 Tohoku-oki earthquake  Deep sea observations of slip to the trench axis  On-going and future projects

 Nankai Trough  NanTroSEIZE  DONET  On-going and future projects NanTroSEIZE: Achievements & Plan (as of Feb-2012) 2007 08 2009 2010 11 2012 2013 2014 15

Exp 314/315/316 319/322 326/332/333 338

Kumano C0009 Obs? Basin 1.6km C0002 Obs Riser 3.6 5.2 7.2 Tophole km km km Obs (1km) Splay C0001 Fault C0003

C0010obs Obs C0004 Landslide C0008 C0018

Acc. Toe C0006 Obs C0007 Shikoku C0011 Basin Temp/ C0012 Basalt Figure courtesy of Masa Kinoshita, IFREE Sakaguchi et al., 2011

High vitrinite reflectance; evidence of frictional heating at the frontal thrust The Cabinet office of Japan officially announced a new model of a rupture zone of the Nankai seismogenic

More than 30 m tsunami at Kochi and 20 m tsunami at the Hamaoka nuclear power plant Landing Station Node DONET for earthquake - tsunami early warning and monitoring crustal activity

Branching Unit

1900m

Backbone Cable

4300m

Ground Motion Sensing System Remotely operated Extension Cable vehicle19 19 Pressure Sensing System and Peripherals Each station consist of Cable  Strong motion

sensor Pressure sensing system seafloor  Broadband

Ground motion seismometer sensing system  Pressure sensor  Differential Finally buried Gimbals Mechanism pressure sensor  Hydrophone  Thermometer

20 - Deployed at C002 in ~ 1km deep - Strain meter, Broad-band seismometer, Borehole observatory geophone, thermometer, presser sensor - will be connected to DONET in 2013

Broadband Strain meter Geophone Seismometer 21 2011: route survey started

2013: deploy a main cable

2014: deploy sensors DONET1 ~ 2015: DONET2

DONET2 ( ( ) is DONET1) DONET2

Backbone cable length： ~350km( ~250km) # of Branching Unit：7 (5) # of Node：7 (5) # of Observation system： 29 (20+2) Strong-motion Broad Band Seismograph Seismograph

Time: 2011.03.11 14:56 (JST)

Mw: 9.0 Out of range Depth 20 km

18分 P wave

14：50：00(JST) 15:00:00 Quartz Differential pressure pressure gauge gauge Kii peninsula

Out of range

KMAKMA02 02 Hydrophone

Precision thermometer From 0.08 to 40Hz Obana & Kodaira , 2009 5 hours before

2 days later

One hour Figure courtesy of Akiko To, IFREE PSD (m2/s4/Hz) in dB Activated after the Tohoku eq. OBS LT-OBS Seismic profile JCG OBS Hinet/Fnet JCG profiles Explosion Relative velocity along to the plate boundary Earthquake

TOKAI eq. NANKAI eq. TONANKAI eq. Coupled HYUGA eq. (Non Earthquake) Figure courtesy of T.Hori & M. Hyodo, JAMSTEC 26 Plate motion

Deployed Tokai3 Planned Kumano2 Nagoya Univ. Tohoku Univ.

Ashizuri1 Tosa1 Muroto1

Tokai1 Kumano1 Tokai2 Kumano3 Shionomisaki2

Hyuga2 Co-seismic Muroto2 displacement of Tosa2 the 2004 EQ Hyuga1 Ashizuri2 Matsumoto(Mw- et al.,7.5) 2008

GPS/A array operated by Hydrographic and Oceanographic Department, JCG Kido et al., 2006 Ocean floor Seismogenic zone Simulation Seafloor and sub- network system drilling seafloor imaging CHIKYU

DONET Super Computer R/V KAIREI Imaging, Monitoring, Modeling and Understanding Seismogenic System

Seismic hazard Precise Damage Estimation

Tsunami hazard For Establishing Early Warning System and Estimating Damage by mega-thrust earthquake

Bilek et al. 2002

Sugioka et al., accepted Slow slip Learn from Tohoku EQ Hierarchical Model: Rupture extending a conditionally stable region may a cause of a giant earthquake

Extended Rupture zone

Conventional model: Jointly rupturing M8-class asperity may a cause of a large earthquake

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