沉积层中的地震波及其震级  

SEISMIC WAVE IN SEDIMENTARY LAYERS AND EARTHQUAKE MAGNITUDE

作　　者：李留藏 孙亚强[1] 李运田 

机构地区：[1]山东省地震局菏泽地震监测中心台

出　　处：《地震》1991年第2期64-72,共9页Earthquake

摘　　要：本文讨论了沉积层中的地震波运动学、动力学的某些特征及对记录近震震级的影响。从理论上推导出,在松散沉积层地区,地震波传至地表面与传至沉积层内h深度某点的走时关系为;而沉积层对地震波(S)的振幅放大作用为。从而得出,在沉积层地区,地面地震仪记录震级高于深井地震仪记录震级的结论。并且,文章对菏泽地震台双套仪器所记录的部分地震进行了统计,其具体关系为M_(L地面)=M_(L沉积层)+0.5。该统计结果与理论结论具有一致性。This paper discussed some kinematic and dynamic characteristics of seismic wave in sedimantary layes and their effects on the local magnitude recording. It is derived theoretically that in loose sedimentary layers, the travel time relation of seismic waves propagating to both the ground surface and one point at the depth h in thesedimentary layer is: T(S-P) ground surface= T(S-P)sedimentary layer + h (2/(VS) -1/(VP)) cosα2;The amplification of sedimentary layer to the amplitude of seismic wave (S) is: Thus we concluded that within a sedimentary layer area.the magnitude recorded by the seismograph at the ground surface is higher than that in the deep well. Authors here have made statistics on some earthquakes recorded by double seds of instruments at Heze seismic station, and their concret relation is ML ground surface = ML sedimentary layer + 0.5. The statistic result and theoretic conclu sion are of consistency.

关 键 词：沉积层 地震波 震级 

分 类 号：P315.3[天文地球—地震学]