A unified source model for the 2011 Tohoku earthquake
Earth and Planetary Science Letters, 310 (3-4):
480--487 (October 2011)DOI: 10.1016/j.epsl.2011.09.009
Abstract
The devastating 2011 Tohoku earthquake was observed by dense networks
of geophysical instruments. A unified source model was constructed
through joint inversion of teleseismic, strong motion, and geodetic
datasets. The result indicates that the earthquake consists of three
main ruptures. After small rupture in the initial 50 s, the first
rupture expanded at a slow speed of 1.8 km/s to the northeast and
east. The second rupture began 20 s later at the slowest speed of
1.5 km/s and became dominant with the largest slip of 36 m. The
third rupture then played the leading role, propagating southward
at a speed of 2.5 km/s. Only the tsunami inversion requires an extension
of the source fault to a shallow part between the first rupture area
and the Japan Trench, recovering tsunamigenic slips larger than 40 m.
The slow rupture speed and tsunamigenic slips can explain the features
of the disaster by the earthquake. ⺠We constructed a unified
source model for the devastating 2011 Tohoku earthquake. âº
The slow rupture speed and large tsunamigenic slips were recovered
in the model. ⺠They can explain the severe tsunami damage
but moderate ground motion damage.