NUMERICAL REPRODUCTION OF THE 2011 OFF THE PACIFIC COAST OF TOHOKU EARTHQUAKE TSUNAMI WAVEFORM OBSERVED AT CHOSHI OFFSHORE

Abstract

 The 2011 off the Pacific coast of Tohoku earthquake, Mw 9.0, occurred on March, 11, 2012. Faulting near the axis of Japan trench produced extraordinarily large tsunamis which do devastating damages to the coastal area in Tohoku.
 In this study, we have examined the applicability of the nonlinear hydrostatic model to the giant tsunami, by comparing the calculated results with the waveform observed at offshore of Choshi city, Chiba prefecture, Japan. The pattern of the observed temporal variation was successfully reproduced for both the surface displacement and horizontal velocities. On the other hand, the magnitude of the temporal variation was underestimated. It is suggested that the underestimate results from the assumption of an instantaneous rupture. We also examined the characteristics of tsunami propagation near Choshi area.