3-D Q STRUCTURE OF THE CRUST AND THE UPPER MANTLE BY TOMOGRAPHIC INVERSION AND PREDICTING STRONG MOTION

摘要

We usually perform the smoothing operation to Q structure obtained by block inversion to emphasize general tendency of spatial variation. We studied the effects of smoothing and grid size on strong motion prediction. First, we studied the effect of the smoothing of 3-D Q structure to seismic ground motion prediction by comparing between observed and calculated acceleration distribution of the 2001 Iwate-Ken earthquake (M6.3, H=130km). The result shows that the small and sharp variety of Q is important for ground motion prediction. Next, we estimated more detailed Q structure in Tohoku district with small block size and without smoothing. Low-Q zones coincident with the positions of Quaternary volcanoes. The result of PGA prediction is consistent with the observed acceleration distribution.