掲載雑誌（和）： 日本地震工学シンポジウム講演集 Vol： 7巻 年： 1986年 頁： 325-330頁 著者（和）： - タイトル（和）： - 抄録（和）：
- キーワード（和）： - 掲載雑誌（英）： PROCEEDINGS OF JAPAN EARTHQUAKE ENGINEERING SYMPOSIUM 著者（英）： Yoshimitsu FUKUSHIMA, Hirosi KAWASE タイトル（英）： THE IRREGULAR GROUND ANALYSES OF MEXICO CITY FOCUSED ON THE TIME-VARYING CHARACTERISTICS OF THE STRONG GROUND MOTION RECORDS FOR MICHOACAN EARTHQUAKE 1985 抄録（英）：
On September 19th, 1985, a destructive earthquake of Ms 8.1 occurred near the coast of Michoacan State of Mexico. Several accelerograms were observed in Mexico City. The accelerograms on soft soil indicate such characteristics as large maximum accelerations and long duration time. The direction of earthquake wave propagation was discussed by cross correlations of two horizontal components. Amplitude ratios off fourier spectra between records in soft soil zone and those in hard rock zone were compared with results obtained by one-dimensional wave propagation theory for alluvium soil profile. However the time-varying characteristics were not obtained by the theory. Thus the ground irregularity was considered to estimate the effect of a diluvial valley. A simple ray theory was performed to simulate the waves reflected in the diluvial valley. It was assumed that rays travel not only vertically, but also horizontally. Analyses by the boundary element method were also carried out. The simulated waves agreed well with the observed ones, particularly in time-varying characteristics. From the result, it was concluded that although the time-varying characteristics can not be explained solely caused by the irregular ground, but the large amplitudes and the longer duration time observed in the ground motions of Mexico City have been strongly affected by the soft alluvial layer and the irregularities of the diluvial layer. キーワード（英）： - 記事区分： - 区分 　　　委員会論文集