The 2011 off the Pacific coast of Tohoku Earthquake: Crustal Deformation and Fault Model (Preliminary)

A mega thrust earthquake with a moment magnitude 9.0 (JMA) occurred in Japan on March 11, 2011 (JST). We constructed a fault model using coseismic surface displacement data observed by the GPS Earth Observation Network System (GEONET).

A fault model which consists of two rectangular faults with a uniform slip in an elastic half-space shows that 

• A total major rupture length reaches ~400 km with a fault width of ~80-90 km. (Northern segment: ~200 km long/ Southern segment: ~180 km long).
• A fault upper edge is at a depth of 10 km.
• A reverse fault motion is inferred. Slip amounts of northern segment and southern one are estimated to be ~28 m and ~6 m, respectively.
• A total moment magnitude is 8.8. (Northern segment: M_w8.7 / Southern segment: M_w8.2) 

This is a preliminary result. We constructed a revised model using additional GPS data which manually collected after restoration of a data transmission system.

New!!  Revised fault model

[PDF: 578KB]


[PDF: 571KB]

Date-Time	March 11, 2011 14:46 JST March 11, 2011 05:46 UTC
Hypocenter Location	38.103°N, 142.860°E, Depth: 24 km (JMA, as of March 13, 2011) 38.322°N, 142.369°E, Depth: 22.4 km (USGS, as of March 13, 2011)
Moment Magnitude	9.0 (JMA, as of March 13, 2011) 9.0 (USGS, as of March 13, 2011)

IMAKIIRE Tetsuro : Principal Researcher for Geography and Crustal Dynamics Research Center
TOBITA Mikio : Director of Division (Crustal Deformation Research Division)
OZAWA Shinzaburo : Chief Researcher (Crustal Deformation Research Division)
NISHIMURA Takuya : Chief Researcher (Crustal Deformation Research Division)
SUITO Hisashi : Cheif Researcher (Crustal Deformation Research Division)
KOBAYASHI Tomokazu : Researcher (Crustal Deformation Research Division)

Coseismic slip distirbution model
Crustal Deformation and Fault Model (Preliminary)
Crustal Deformation (In Japanese)