SEGJ Technical Conference

Extracting the surface-wave phase velocity in the southern Kanto area using Seismic Interferometry Part2. Validation of 3D S-wave velocity model

Abstract Surface wave group velocities were extracted with processing continuous data of three-component microtremors in the Kanto basin and Izu peninsula using the procedures based on the seismic inferferometry in order to validate the existing 3D S-wave velocity model of deep sediments by Yamanaka and Yamada in 2006. Cross correlations were calculated from the microtremors for every station pairs among 16 sites in the area. Dispersive waves in the cross correlations were identified as surface waves between the two sites. The group velocities for Love and Rayleigh waves were estimated from the multiple filtering analysis of the cross correlation. The observed group velocity of Rayleigh waves were compared with the theoretical ones calculated form the 3D S-wave velocity model of the deep sedimentary layers. The observed group velocities are similar to the theoretical ones at most of the sites in the basin area. However, significant differences were identified for the station pairs across the Sagami bay area and the Kanto mountains. It is concluded that the S-wave velocity in such an area must be improved.