SEGJ Technical Conference

Estimation of group velocities based on seismic interferometry analysis on microtremor records observed with Hi-net stations in Iwate Prefecture

Abstract In order to estimate the S wave velocity structure such as the depth of the earthquake bedrock, based on the seismic wave interferometry, we calculated one-month stacked cross correlation functions (CCFs) at the 27 stations in Iwate prefecture of the Hi-net, estimate the group velocities, and compared observed velocities with calculated ones from the S wave velocity structure model by Nishida et al.(2008). As a result, we could see the characteristic phases propagating in the one-month stacked cross-correlation functions. Furthermore, we could obtain the group velocities at periods of about 1 second to about 7 seconds. From the group velocity distribution at 2 and 3 s periods, we could find that the difference between observed velocites and calculated ones in Kitakami Mountains was small but the difference was large in the northwestern part of Iwate Prefecture and the southwest part of Iwate Prefecture.