Estimation of Fault Strength: Reconstruction of Stress Before the 1995 Kobe Earthquake
Futoshi Yamashita,*
Eiichi Fukuyama,
Kentaro Omura
We have estimated the stress field before the 1995 Kobe, Japan,
earthquake (moment magnitude 6.9) using in situ post-shock stress
measurements obtained from hydraulic fracturing experiments
near the fault. We reconstructed the pre-shock stress field
using a kinematic source model inverted from seismic waveforms
and geodetic deformations. We found that at the center of the
fault, two sides of the fault surface coupled completely before
the earthquake, with a coefficient of friction of 0.6, which
is equivalent to strong crust. At the edge of the fault, a possible
aseismic slip is expected to occur from the pre-shock stress
orientation.
* To whom correspondence should be addressed. E-mail: yamafuto{at}bosai.go.jp
