泰安地区近震波速及地壳厚度的测定

SURVEY OF NEAR EARTHQUAKE WAVE VELOCITY AND THICKNESS OF THE EARTH'S CRUST AROUND TAI'AN AREA

本文第一部分选取泰安台473型地震仪1985—1990年记录的70个地震资料,通过计算,得到泰安台附近的地壳厚度为H=36.5km,直达波的平均传播速度:V_P=6.18km/s、V_s=3.55km/s;反射波的传播速度:V_(P11)=6.45km/s、V_(S11)=3.79km/s;绕射波的传播速度:V_(Pn)=7.95km/s;平均虚波速度:V_φ=8.34km/s;平均波速比K=1.74。第二部分选取了泰安台基式地震仪有SP′震相记录的地震21个,求出了泰安台附近的地壳厚度为37km,并分析了SP′震相在泰安台的记录特征,初步得到SP′震相可观测范围为25°—60°。

With seventy earthquake records from 1985 to 1990 recorded by the model473 seismograph at Tai'an station, authors calculate in the first part of the pa-per that the crust thickness around Tai'an is H= 36. 5km and the average trave-lling velocity of direct waves is V_p^-= 6. 18 km/s, V_s^-= 3. 44km/s; that of refle-cted waves, V_(pll)= 6. 45km/s, V_(sll)= 3. 79km/s, that of diffracted waves, V_(pn)= 7. 95km/s; for imaginary waves, Vφ= 8. 34km/s, and the average ratio of Wave velo-cities, K=1. 74. With the data of twenty-one earthquakes that have records of the SP' phaserecorded by tape-SK seismograph at Tai'an station, the authors find out, in thesecond part of the paper that the crust of that region is 37km thick, and by ana-lyzirg the features of SP' phase at Tai'an station preliminarily conclude that theSP' phase is observable in the range of 25°--60°.