Permalink : http://hdl.handle.net/2115/44472

JaLCDOI : 10.14943/gbhu.73.175

I modify a vertical array analysis method that decomposes complex seismograms into body and surface wave time histories that have been proposed by Yoshida and Sasatani（2008）. In the previous study, P, S and surface waves at the surface were decomposed by a least-squares method without any weighting. In the present study, the data are weighted by using the maximum amplitude of each spectrum of seismograms. I carried out a numerical test of this method with synthetic vertical array records consisting of vertically incident plane P and S waves and laterally incident plane Love and Rayleigh waves. P, S, Love, and Rayleigh waves were perfectly decomposed for synthetic records without noise. I applied this method to real vertical array records from the Ashigara valley, a moderate-sized sedimentary valley. The array records from an earthquake occurring at the depth of 123 km near the array（epicentral distance of about 31 km）I find small difference between the present weighted and the previous non-weighted estimations.