摘要
本文选取阳原台 DD- 2型地震仪在 1 998— 1 999年间记录清晰、可靠的 50次张北地震和记录到 Pn震相的 2 5次地震资料。通过计算 ,得到京西北地区直达波的平均传播速度为 :Vpg=5.99km/s,Vsg=3.47km/s,平均波速比 Vpg/Vsg=1 .73,京西北地区的地壳厚度为 41 Km。
The data of 50 Zhangbei after shocks and the Pn seismic phase of 25 aftershocks recorded clearly and reliably by DD-2 Seimograph of Yangyuan seismostation during 1998 to 1999 period are analyzed.Through calculation we get the following results:the mean propagation velocity of direct wave in northwest Beijing area is Vps =5.99Km/s, Vsg =3.47Km/s,mean Vpg/Vsg =1.73,the crustal depth of the region is 41km.