Abstract
　The following two kinds of empirical relations are derived: l) relations between the P-wave velocities and geological factors (facies, time and depth), based on oil well data in Akita prefecture; 2) relations between the S-wave velocities and the P-wave ones, based on published and new data from in situ velocities measurements in relatively decp boreholes in Japan. Combination of the above two relations provides means for estimating the S-wave velocities from geological factors. A VSP experiment was carried out in a well of 1.3 km depth in Akita prefecture to provide this study with S- and P-wave data of oil field area. To demonstrate the purpose of this study, calculations of ground vibrations due to the vertically incident SH-waves are conducted for a two-dimensional seismic structure model corresponding to a typical sedimentary basin in Akita prefecture.

【キーワード】：地震波速度，S波，深層地盤，地震動予測
Key words: seismic wave velocities, S wave, deep soil doposits, earthquake ground motion evaluation.

*秋田大学鉱山学部資源・素材工学科
Department of Geoscience, Mining Engineering
and Material Processing, Mining College Akita University
**室蘭工業大学情報工学科
Department of Computer Science and Systems Engineering, Muroran Institute of Technology.
!京都大学理学部地球物理学教室
Geophysical Institute, Faculty of Science, Kyoto University
!!地球科学総合研究所
JAPEX Geoscience Institute Inc .
#大阪工業大学建築工学科
Department of Architectural Engineering, Osaka Institute of Technology
##岩手大学工学部資源開発工学科
Department of Mining Engineering, Faculty of Engineering, Iwate University
%秋田大学大学院鉱山学研究科鉱山地質学専攻
現地熱技術開発KK
Geothermal Energy Research & Development Co.
%%もと秋田大学大学院鉱山学研究科鉱山地質学専攻
現三井金属資源開発KK
Mitsui Mineral Development Engineering Co.