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| | Abstract | | Three-component microtremor exploration with a large size array was conducted in Aoyama and Motomiya districts located in an urban area of Morioka city. We have succeeded in estimating Love wave phase velocities by using two methods of spatial autocorrelation method and frequency wavenumber analysis method under noisy observation conditions such as traffic noises. The phase velocity dispersion curve of Love waves was obtained even with an array radius of 100m, which was larger than one used in previous studies. However, there were some cases where the dispersion curve varied at radii of 400m and 1000m. It is thought to be due to change spatially sin the basement depths of the Aoyama and Motomiya districts. When the S wave velocity structure was estimated using only the Rayleigh wave obtained from the microtremor data of the vertical motion, there was a trade-off between the layer thickness and the S wave velocity, and the S wave velocity structure was not uniquely determined. When the S wave velocity structure was estimated using the wave dispersion curve of Love and Rayleigh waves, the constraint conditions increased and the S wave velocity structure could be estimated uniquely. |
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