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| | Abstract | | We compared the results of the CCA microtremor survey, PS-logging and the Shallow structure model of the Osaka basin. Microtremors were observed at 18 sites along the east-west profile across the Uemachi fault in the Osaka basin with a miniature array (0.6 m radius) and a centerless small array (about 10 m of the side angle). Observed phase velocities are obtained in the frequency of 0.8-30 Hz using the centerless circular array method (CCA). We calculated theoretical phase velocities of the fundamental, first-higher and second-higher mode Rayleigh waves for the Osaka sedimentary basin model and the PS-logging structure. The phase velocities by the CCA are similar to the theoretical ones of the fundamental mode on a frequency lower than 5 Hz at the most of the array site. We made a cross section of the profile from the CCA results with a simplified inversion technique. This cross section consists with the Vs cross section of the Osaka sedimentary basin model. |
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