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| | Abstract | | We conducted microtremor explorations at 15 sites in the Bandung basin, Indonesia, to know S-wave velocity profiles of shallow and deep soils for estimating amplification of strong ground motion during large earthquakes in the area. We temporarily deployed an array of 10 vertical seismometers with station spacing of 0.2 to 1 km at each site using stand-alone recorders with GPS timing signal to obtain microtremor data of 45 minutes. Then, small arrays were also deployed near the center of the large array by installing 7 vertical sensors in triangular configurations with spacing of 2-16 meters at each site. Vertical array records of microtremors were used to estimate Rayleigh wave phase velocity using SPAC or FK methods. Preliminary analysis of the obtained records indicates that phase velocity at the sites in the basin margin exhibits higher values than those obtained in the central part of the basin in high and low frequencies ranges. This clearly indicates that the thickness of the sediments is larger in the center of the basin. |
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