用Lg波资料反演场地效应与地震波衰减参数  

AN INVERSION OF SITE RESPONSE AND Lg ATTENUATION USING Lg WAVEFORM

作　　者：朱新运[1,3] 陈运泰[1,2] 

机构地区：[1]中国地震局地球物理研究所,中国北京100081 [2]北京大学地球与空间科学学院,中国北京100871 [3]浙江省地震局,中国杭州310013

出　　处：《地震学报》2007年第6期569-580,671,共12页Acta Seismologica Sinica

基　　金：浙江省科技计划项目(2007C33060);国家科技支撑计划(2006BAC01B03-04-02)资助

摘　　要：基于谱比法，以台站记录地震波频谱为观测数据，通过扣除仪器响应及几何扩散后同一地震不同台站记录谱比，扣除震源方向性、震源因子的影响，在此基础上，建立数学模型通过联合反演求解场地效应及地震波衰减参数．以浙江省地震台网台站记录的台湾地震数字化地震波资料为基础，使用地震波记录中的Lg波，评估浙江省台网丘陵地带基岩台站场地效应，计算穿越台湾海峡较单一路径Lg波衰减参数．研究使用20次发生于2002-2005年、震级在Ms5．0～6．7之间的台湾东北部较小区域地震，参与评估台站16个，地震波记录960条．地震波处理频段为0．5～10．0Hz，每间隔0．2Hz计算一次，对应于垂直、东西及南北分量获得的衰减参数，数据结果分别为：γ（f）=0．00175f^0.43485,γ（f）=0．00145f^0.48467，γ（f）=0．0021f^41241．庆元台（QIY）在1．5Hz以上放大效应非常明显，宁波台（NIB）在大部分频率点场地效应最小，参与评估台站场地效应各分向基本相当，未表现出方向性特征．Based on spectral ratio method, a joint inversion method was used to obtain parameters of Lg wave attenuation and site response. The inversion method allows simple and direct （two-parameters） determination of Lg wave attenuation and site response from sparse spectral data, which are not affected by radiation factor and different response of same instrument after geometrical spreading. The method was used successfully for estimating site response of Zhejiang seismic network stations and measuring Lg wave attenuation. The study is based on 20 earthquakes occurred in northeast of Taiwan with magnitude Ms5.0-6.7 and 960 seismic wave records from 16 stations in Zhejiang area from 2002 to 2005. The parameters of site response and Lg attenuation were calculated with an frequency interval of 0.2 Hz in the range of 0.5-10 Hz. Lg wave attenuation coefficient corresponding to U-D, E-W and N-S components are γ（f） =0.00175f^0.43485 ,γ（f） =0. 00145 f^0.48467 and γ（f）=0. 0021f^0.41241 , respectively. Site response of QIY station is significant above the frequency of 1.5 Hz, However, site response of NIB station are low for most frequency. The site response are found to be component independent.

关 键 词：LG波 场地效应 衰减参数 联合反演 

分 类 号：P315.3[天文地球—地震学]