SEMI EMPIRICAL SIMULATION OF STRONG GROUND MOTION

Abstract

The strong ground motions for the Tohoku earthquake (Mw = 9.1) of 11 March, 2011 has been simulated in this dissertation using semi empirical technique. This approach is based on.the ,. modeling of the rupture plane, initially semi empirical approach was started by Midorikawa- . (1993) and further modified by Joshi (2004). In this technique, the rupture plane. of the target_, event is divided into several subfaults, their number of subfaults and geometry is decided on the basis of self-similarity laws and scaling relationship of Kanamori and Anderson (1975). In this report simulation of strong ground motion for this earthquake has been done by a simple -rectangular rupture plane of dimension 510 x 210 square lam, buried at a depth of 10 km in a multilayered earth model. In this work, records have been simulated at nine different ,stations and are compared with the observed records and their: response. Several models,has been considered for comparison and iterative forward modeling is performed to finalized various parameters of the rupture plane of the Tohoku earthquake like- number of subfaults, position of nucleation point, rupture velocity and dip of the rupture model. The final selection of model- parameter is based on the root mean square error between .: the observed and recorded accelerogram at L maximum four stations. Iterative forward modeling and comparison of observed and simulated record at nine different stations support northward propagating rupture with high rupture velocity of 3.5 km/sec for this earthquake