Abstract
The microtremor array observations and the 3-components single site observations were conducted to clarify the S-wave velocity structure of the Ohno basin in Fukui Prefecture. The Rayleigh wave phase velocities at each array site were calculated by the spatial autocorrelation method. The phase velocities at each site were inverted to a 1D S-wave profile using a genetic inversion. The subsurface structures down to the Neogene were back analyzed based on the H/V spectra. The 3D S-wave velocity structure around the Ohno Basin was interpolated by using Kriging techniques. The validity of the estimated structure from the microtremor observation was confirmed by comparing with the density structure and with the existing boring logging data. The estimated S-wave velocity structure indicated that the newly developed urban area of Ohno city was located on the low velocity zone.
