第二影区地震震相到时特征变化浅析  

A Brief Analysis on the Change of Arrival Time Characteristics of Seismic Phase in the Second Shadow Area

作　　者：陈凯男 刘立申[1] 王利兵[1] 赵志远[1] 宋昭[1] 罗娜[1] 贾华[2] CHEN Kai-nan;LIU Li-shen;WANG Li-bing;ZHAO Zhi-yuan;SONG Zhao;LUO Na;JIA Hua(Hongshan Seismological Station,Hebei Seismological Bureau,Xingtai,Hebei 054000,China;Hebei Seismological Bureau Handan Center Station,Handan,Hebei 056002,China)

机构地区：[1]河北省地震局红山基准地震台,河北邢台054000 [2]河北省地震局邯郸中心地震台,河北邯郸056002

出　　处：《山西地震》2021年第1期1-4,共4页Earthquake Research in Shanxi

基　　金：河北省地震局科技星火计划项目(DZ20150422041)。

摘　　要：运用国家台甚宽和超宽频带地震计记录的波形数据,对震中距介于105°~128°(即第二影区)的地震波形进行仿真处理,分析各台站地震波由地幔传播到核幔交界面时,各震相记录特征发生的变化。结果表明,当震中距增大到105°左右时,地震波进入到核幔过渡带这一复杂的低速层中,地震波能量衰减加快;P波与Pdif波震相未表现出明显的分界,S波震相也未出现断崖式消失,且随着震中距的增大还会出现。这也间接印证这一低速层的不均匀性。Based on the waveform data recorded by the very wide and ultra-wide band seismometers of national seismological stations,the seismic waveforms with the epicenter distance between 105°and 128°(the second shadow area)were simulated,and the changes of the recorded characteristics of each seismic phase were analyzed when the seismic wave propagates from the mantle to the interface between the core and mantle.The results show that when the epicentral distance increases to about 105°,the seismic waves enter the complex low-velocity layer called the core mantle transition zone,and the energy attenuation of seismic waves is accelerated.The seismic phase of P wave and Pdif wave will not show obvious boundary,and the seismic phase of S wave will not appear cliff-like disappearing,but will also appear with the increase of epicentre distance.This also indirectly confirms the unevenness of this low-speed layer.

关 键 词：震相特征 第二影区 核幔过渡带 

分 类 号：P315.73[天文地球—地震学]