摘要
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。
Based on the method of “two dimensional depth structure of the crust” proposed by Horiuchi et al.,about 4000 arrival times of 303 local shallow earthquakes recorded by the Beijing Seismolographic Network during 1990～1993 were used to investigate the depth distributions of Moho discontinuity beneath the Beijing and its adjacent area.We simultaneously determined the hypocenter parameters,P and S wave station corrections.Otherwise,the data of the North China Network were investigated too. The results shown as follows:(1) The depth distributions of Moho discontinuity becomes shallower from the northwest to the southeast.That is,in Zhangjiakou area,the Moho discontinuity is located at a depth range from 40～42km.In Beijing area,it is 36～39km.But at eastern and southeastern part of this area,it is only 28～30km and 30～32km.(2) Beneath Tangshan area,there is another elliptic surface shallower than Moho discontinuity.Separately,its major and minor axis is along the direction of east west and south north approximately.Its center is located about at a depth of 13～15km.But its boundary is not clear.(3) Part of the basement rock in mountain area were naked.The sedimentary layer in hollow area is comparatively thicker,and the maximum value is about 6.2km.
出处
《中国地震》
CSCD
北大核心
1998年第1期1-13,共13页
Earthquake Research in China
基金
地震科学联合基金会
关键词
地壳
深度结构
Moho面
台站校正值
地震
震源
Two Dimentional depth structure of the crust,Moho discontinuity,Station correction
