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利用北京台网38个台站记录的北京及其附近地区1990~1993年303个20级(唐山地区30级)以上地震,共3014条P波到时、666条Pn波到时及1135条S波到时资料,采用Horiuchi等(1982a;1982b)提出的“地壳二维深度结构”方法,研究了这一地区Moho面的深度分布特征,同时联合测定震源位置及P,S波台站校正值。另外,用华北台网(1993,1994年)的资料也进行了试算。结果表明:(1)Moho面的深度分布明显由西北向东及东南方向递减,即北部山区张家口附近最深,可达40~42km左右,北京地区为36~39km,而位于东部的秦皇岛、北戴河一带则约为28~30km,东南部约为30~32km;(2)在唐山附近有一以唐山为中心、东西向为长轴、南北向为短轴的近似椭圆形分布的界面(约1°×2°),该界面边界模糊,中心深度约为13~15km;(3)山区部分基岩裸露,凹陷区沉积岩层相对较厚,最厚约为62km。
A total of 3014 P waves arrived in Beijing and its vicinity from 303 stations of 20 in 1990 ~ 1993 (30 in Tangshan area) recorded by Beijing station and 38 stations, and 666 Pn waves arrived And 1135 S-wave arrival data, the depth distribution of the Moho surface in this area was studied by using the method of “two-dimensional Crustal structure” proposed by Horiuchi et al. (1982a; 1982b) Station correction value. In addition, with the North China Network (1993, 1994) data also conducted a trial. The results show that: (1) The depth distribution of Moho surface obviously decreases from northwest to east and southeast, which is the deepest near Zhangjiakou in the northern mountains, reaching 40-42km, while Beijing is 36-39km. In the eastern part of Qinhuangdao and Beidaihe About 28 ~ 30km, southeastern about 30 ~ 32km; (2) near the Tangshan Tangshan as a center, east-west long axis, north-south axis of the approximate minor axis of the distribution of the interface (about 1 ° × 2 °), the boundary of the interface is fuzzy and the center depth is about 13-15 km. (3) Some basement rocks in the mountain area are bare and the sedimentary rock layers in the depression area are relatively thick with a maximum thickness of about 62km.