山地与平原地形对地震动影响的对比分析

Comparison of the Effects of Mountainous Regionsand Sedimentary Plains on Ground Motion

摘要:

山地和平原地形在破坏性地震中对震害和地震动有很大影响，不同地形对地震动有不同的地形效应。为研究山地和平原地形对地震动的影响规律，基于集集地震后续M_L6.6余震的强震观测记录，对位于不同地形且与震中位于同一直线上的四个强震台记录处理计算，从波形特征、频谱分析、加速度反应谱计算、与规范谱比较等方面进行对比分析，完成长周期地震动反应谱分布的计算。研究表明，山地地形对地震动的高频成分有地形放大效应，沉积平原对地震动的低频长周期部分有放大作用，并且长周期反应谱的峰值区域始终位于沉积平原中部。平原上强震记录产生的长周期放大系数谱已超出规范谱，沉积平原上长周期建筑的抗震设防应引起重视。

Abstract:

Mountainous regions and sedimentary plains have different amplification effects on the strong ground motions and damage arising from destructive earthquakes. To obtain the influence rules of these two terrains, based on the strong-motion records from the M_L6.6 aftershock of the Chi-Chi earthquake, we processed and analyzed records from four strong-motion stations located in different terrains and along the same line with the epicenter. Then, we compared and analyzed the calculation results from many aspects and obtained the distribution of the long-period response spectra of ground motion. The results show that the high-frequency components of the input earthquake motion are amplified by a mountainous region, and the long-period components of the input earthquake motion are amplified by a sedimentary plain. We found the peak value of the long-period response spectrum located in the middle of the sedimentary plain. The long-period amplification coefficient spectra of the strong-motion records on the sedimentary plain are beyond the range of the seismic design code. Consequently, more attention should be paid to the seismic fortification of high-rise buildings on sedimentary plains.