地震测深中的地震波衰减

SEISMIC ATTENUATION AND EXPLOSION SPECTRA FOR DEEP SEISMIC SOUNDING IN THE STUDY OF THE CRUSTAL AND UPPER MANTLE STRUCTURE

摘要:

基于在河南、湖北、江苏、安徽等省和西藏自治区进行的人工地震测深工作,详细分析了不同爆炸方式(水中爆炸、井中组合爆炸、矿山和洞室爆炸),不同炸药量(1.2～500吨)和不同观测距离(5～500公里)的实测资料,讨论了爆炸方式与衰减的关系。结果表明,水中爆炸的弹性波转换系数最大,并以组合爆炸方式获得最佳的效果。本文提出地震测深中的地震波衰减遵循关系式:
V_m=β(R/W^1/3)^-r
式中,V_m 为地表运动最大速度,(R/W^1/3) 为折合距离,r为衰减系数。(r=1.5～1.6)。文中简要讨论了地壳厚度与地震波衰减的关系。

Abstract:

We have analysed,in detail,seismic trace for the shot point and dif-ferent receiver points and proposed different explosion spectra on the ba-sis of modes explosion of such as underwater,cluster in the wells,blast and cave explosions and observable seismic data in the region about 5- 250km.The predominant frequency is 6,7,5 and 9 Hz for underwater, cluster in the wells,blast and cave explosions respectively.The attenuat-ion of peak-value of ground maximum velocity with distance is represented by(R/W1/3)-1.5-(R/W1/3)-1.6We have simply analysed the relation-ship between the observable distance and charge as well.