Characteristics of long period microtremor and validation of microtremor array measurements in inland areas of China  

作　　者：CHE Ai-lan ZHANG Teng-yu FENG Shao-kong CHE Ai-lan ZHANG Teng-yu FENG Shao-kong(School of Naval Architecture,Ocean and Civil Engineering,Shanghai Jiaotong University,800 Dongchuan-Road,Shanghai 200240,China)

机构地区：School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiaotong University, 800 Dongchuan-Road, Shanghai 200240, China

出　　处：《Journal of Mountain Science》2016年第11期1910-1922,共13页山地科学学报（英文）

基　　金：financially supported by the National Natural Science Foundation of China(Grant No.11372180)

摘　　要：To study the characteristics of long period microtremor and applicability of microtremor survey,we have made microtremor observations using long period seismometers of the China's mainland from coastal cities like Shanghai and Tianjin through Beijing,Xi'an,to the far inland cities of Lanzhou and Tianshui.The observation shows that the level of power spectrum of long period microtremors reduced rapidly from the coast to the inland area.However,the energy of long period microtremors in Beijing,Xi'an,Lanzhou and Tianshui area are only approximately ten-thousandth to thousandth of that in Shanghai.Aiming at the complexity of the underground structure in the far inland,a series of underground structure models with different distributions were assessed using three-dimensional,dynamic finite element method(FEM) analyses.The results were used to evaluate microtremor survey methods and their limitations with regard to aggregate variability and thickness determinations.Multiple-wave reflections between layers with the change of underground structure distribution occurred,which have significant effect on the performance of the different field approaches.Information over a broad spectrum from which velocity-depth profiles were produced via inversion approaches.Neither the thickness nor the shear waveVelocity V of the subsurface layer inversion results appeared over a large evaluation with increasing slope angle.In particular,when the angle of the model reached 45°,it could not be accurately evaluated using one-dimensional inversion methods.Finally,the array microtremor survey(AMS) was carried out in Shanghai City,China.Although AMS techniques do not have the layer sensitivity or accuracy(velocity and layer thickness) of borehole techniques,the obtained shear wave velocity structure is especially useful for earthquake disaster prevention and seismic analysis.

关 键 词：Long period microtremor Array Microtremor survey Power spectrum INVERSION S-wave velocity structure 

分 类 号：P315[天文地球—地震学]