Confirmation of Nonlinear Site Response: Case Study from 2003 and 2005 Miyagi-Oki Earthquakes

Kenichi Tsuda, Ralph J. Archuleta, & Jamison H. Steidl

Published 2006, SCEC Contribution #1107

We have confirmed the nonlinear site response from observed data of the 2003 (Mw7.0) and 2005 (Mw7.2) Miyagi-Oki earthquakes. Both events produced large peak ground accelerations (PGA), suggesting that a nonlinear site response could exist. We calculated the surface site responses for K-NET and KiK-net stations using weak motion data with source and path parameters determined by a spectral inversion of KiK-net borehole records. We compared these site responses to those derived from strong motion data. This comparison suggests that nonlinear site response occurred at many stations. We also did 1D simulations of wave propagation that incorporated soil nonlinearity. The results of the nonlinear simulation agreed better with the observed data at surface than the results of the linear elastic case.

Citation
Tsuda, K., Archuleta, R. J., & Steidl, J. H. (2006). Confirmation of Nonlinear Site Response: Case Study from 2003 and 2005 Miyagi-Oki Earthquakes. Bulletin of the Earthquake Research Institute, 81(3/4), 303-307.