中国地区地震P波和S波走时表
P AND S TRAVEL TIMES FROM EARTHQUAKES IN THE CHINESE REGION
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摘要: 本文搜集了1952-1971年发生在我国境内及边境地区266次地震的观测资料,得到国内外五百多个地震台的 P 和 S 震相到时约二万条;根据我国地区大爆炸观测及其他地壳结构的研究成果,结合上述地震观测资料,提出了中国地区双层平均地壳速度模型,以便由深度走时校正把各种震源深度上的走时折算为表面震源走时,并进行剥壳处理.用迭代法校正震中和发震时刻.采用1970年寇蒂斯(curtis)所述的立方样条函数平滑数据的方法,得到表面震源 P 波和 S 波的走时表.运用海格劳兹-维谢尔特-贝特曼(Herglotz-Wiechert-Bateman)速度反演的方法求得中国地区地幔中,P 波和 S 波速度随深度的分布.算出震中距离=0-104,各种震源深度的一整套 P 波和 S 波走时表.经过试用的实践表明,用它来测定震中参数比用国外的走时表具有较高的精确度.Abstract: In this work, we collected the observed data of 266 earthquakes occurred in China and its bordering region during the years 1952-1971. A total of some 20,000 arrivals of P and S waves were available from more than 500 seismological stations at home or abroad. In order to reduce the travel time data of all earthquake focal depths to that of surface foci, and to strip the earth's crust, a 2-layer average velocity model of the crust for the region was proposed based on observations of large explosions and results of some other studies of crustal structure, combined with the above mentioned data of seismological observations. All of the earthquake epicenters and origin times have been revised by an iteration procedure. The smoothing technique of cubic splines as described by Curtis (1970) was applied for the P and S travel times for surface foci. The Herglotz-Wiechert-Bateman method was used to inverse P and S velocity distribution with depths in the mantle for this region. Finally, a set of travel times tables of P and S waves for various focal depths were constructed in the epicentral distance range of △= 0-104. Practical experiences show that the new tables have been relatively improved in accuracy for epicentral location of earthquakes of this region than other tables.