The damage pattern observed during the 1819 Kutch earthquake and 2001 Bhuj earthquake of magnitude [Formula: see text] in India implied the significance of the effect of Kutch basin on seismic ground motion. In the present study, the Kutch rift basin is modeled as a simplified rectangular basin of size 150[Formula: see text]km [Formula: see text] 90[Formula: see text]km [Formula: see text] 1.5[Formula: see text]km. The shear wave velocity of the Kutch region varies from 300[Formula: see text]m/s at the surface to 800[Formula: see text]m/s at the depth of 60[Formula: see text]m. Three-dimensional ground response analysis is carried out for the simplified Kutch basin subjected to ricker wave, using the spectral element code SPEED. The soil medium is modeled through visco-elastic soil model, where the damping is represented by Quality factor. It is found out from the numerical analysis that maximum amplification of 3.6 times occurs at the corner of the basin where interference of waves reflected from multiple edges happen. The long period structures with fundamental period in the range of 1.5–2.5[Formula: see text]s located near the basin edge are found to be significantly affected by the basin effect.

中文翻译：

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谱元法简化卡奇盆地3D地面响应分析

在印度 1819 年 Kutch 地震和 2001 年 Bhuj 地震[公式：见正文]期间观察到的破坏模式暗示了 Kutch 盆地对地震地震动的影响的重要性。在本研究中，Kutch 裂谷盆地被建模为一个简化的矩形盆地，大小为 150[公式：见正文]km [公式：见正文] 90[公式：见正文]km [公式：见正文] 1.5[公式：见文字]公里。Kutch 地区的横波速度从地表的 300[公式：见文]m/s 到 60[公式：见文]m 的深度处的 800[公式：见文]m/s 不等。采用谱元代码SPEED对受Ricker波作用的简化Kutch盆地进行三维地面响应分析。土壤介质通过粘弹性土壤模型进行建模，其中阻尼由品质因子表示。数值分析发现，在盆地的拐角处出现了3.6倍的最大放大，多棱反射波发生干涉的地方。发现位于盆地边缘附近的基本周期在1.5~2.5[公式：见正文]的长周期构造受盆地效应影响显着。