Expectations for international MARGINS' collaborations from the point of view of an

"active margin" country

Gaku KIMURAThe University of Tokyo

iFREE JAMSTEC

One Day Suddenly!

2004　 Sumatra Tsunami1944 Tonankai Earthquake Mie Prefecture

Top 12 since 20C

1906 Equador1923 Kamchatka1938 Banda1950 Tibet1952 Kamchatka1957 Alaska1960 Chile 1963 Kuril1964 Alaska1965 Rat Alaska2004 Sumatra2005 N.Sumatra

Nankai Trough: Longest Historical Record

Ide et al., 2007

Obana & Kodaira, 2009

国土地理院／世界最稠密 GPS南海トラフ

Recent Great Discoveries

Obara, Science 2002, Ito et al., Science 2007, Ide et al., Nature 2007

Plate boundary depth contour

Rupture AreaRupture Area

Rupture Area

Deep Low Frequency TremorDeep ultra-low Frequency TremorSlow slip

Shallow ultra Low Frequency Tremor

Soon: Direct observation within fault zone bore hole

Recent Great Discoveries : far field observation

Deep LFT

Shallow LFT

Chikyu

Moore et al., 2009

Splay Fault

Oceanic Crust Decollement

3D Nankai accretionary wedge

Moore et al., 2007, 2009

The splay Fault from the bottom

Many landslides around active portion of the splay fault

Horizontal slice at -2910m

Clear deformation ofyoung (<0.5My) slope sediments

南海トラフ海底地形・断面図

フィリピン海プレート

Splay Fault

10cm

X-rayCT

Drilling Result of the splay fault Kinoshita, Tobin et al., 2009

1944 Tonankai!Disturbed mud is a key

Analyzed byYamaguchi et al.

Conclusion1. Nankai Trough SEIZE is a quite successful on-

going international collaboration through individual PIs, IODP frame, Margins program and others.

2. International collaboration is strongly expected from “active margin” countries because natural geo-hazard issues are so serious and urgent.

3. A new frame of international MARGINs is expected in each country.