广元市地震波能量分布特征及地质灾害响应

根据汶川地震中广元市曾家站记录的强震数据及地震诱发崩滑的野外资料,对地震波能量分布特征进行了研究,得出广元市地震波能量最集中的时间段为60～80s,主要频率约为2.7Hz。在此基础上,分别从地形地貌、地层岩性、地质构造及地震波特性几个方面,初步分析了研究区地震诱发地质灾害在空间上的响应特征。研究区地质灾害的空间分布集中在800～1 800m的低、中山区;30°～50°的坡度地段;易破碎、发育裂隙的变质岩、软硬岩互层的地层;断裂构造延伸方向、断裂构造交汇处以及山体斜坡地脉动卓越频率大于地震动主频率的地区。研究区内东河口滑坡发生在地震波能量最强烈最集中的时段,经研究表明,该区地质灾害的时空响应特征与地震波能量在时间及空间上的分布有较好的一致性。

Research on Distribution of Seismic Wave Energy and Response of Geologic Hazards in Guangyuan

According to the strong ground motion records from the Wenchuan earthquake at the Zengjia station in Guangyuan and the field data of the earthquake-induced collapse and landslide,the distribution of seismic wave energy was investigated in this study.The results suggested that the period of the largest accumulation of seismic wave energy is 60~80 s and the main frequency is about 2.7 Hz.Following this,this paper analyzed the spatial characteristics of the response of the earthquake-induced geologic hazards in the study area from the aspects of geomorphology,lithology,geological structure,and performance of earthquake wave.The geologic hazards occurred mainly at the mountain area with an elevation of 800~1800 m;at the area with a gradient of 30°~50°;at the metamorphic rock stratum with intense weathering and fracture development,and the stratum with an interbedding of soft and hard rock;and at the area of the extension direction and intersection of the fault structure,and the area with a higher predominant frequency than the main frequency of the ground motion.In the study area,the Donghekou landslide occurred in a period with the most cumulative of seismic energy.Moreover,the results indicated that the spatial and temporal characteristics of the response of the geologic hazards are consistent with those of the seismic energy.