学会誌「自然災害科学」

自然災害科学42 Vol.16,No.2, 1997, p125f

【論文】[Regular Paper]

観測記録と数値シミュレーションから推定される1995年兵庫県南部地震によるやや長周期地震動の伝播特性

Propagation Characteristics of Long Period Ground Motion During the 1995 Hyogo-ken Nanbu, Japan, Earthquake Estimated From Observation and Simulation

片岡 俊一*・片岡 正次郎**・大町 達夫***

Shun'ichi KATAOKA*, Shojiro KATAOKA** and Tatsuo OHMACHI***

Abstract

To deepen our understanding on long period ground motion used for seismic design, the ground motion in the Osaka basin due to the 1995 Hyogo-ken Nanbu earthquake is studied. First, peak frequencies observed at Fukushima in Osaka city are discussed with the underground structure. Then, direction and velocity of wave propagation are estimated, using up-down component observed at very densely spaced stations in Osaka city. The velocities are close to the phase velocity of the fundamental mode of Rayleigh wave. Propagating direction is about N30W, indicating that the long period ground motion is predominated by the surface waves affected by 3-D topographical conditions. Using boundary element analysis, the 3-D effects on the ground motion is investigated, with a result that the long period ground motion is propagated from N40W direction with surface wave velocity.

キーワード:

1995年兵庫県南部地震，大阪堆積盆地，表面波，センブランス解析，3次元境界要素法

Key words:

the 1995 Hyogo-ken Nanbu earthquake, Osaka basin area, surface wave, semblance analysis, 3-D BEM
*
清水建設(株)技術研究所(東京工業大学大学院総合理工学研究科在籍中)
Institute of Technology, Simizu Corporation (Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology)
**
カリフォルニア工科大学土木工学科
Department of Civil Engineering, California Institute of Technology
***
東京工業大学大学院総合理工学研究科
Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology