【摘要】 <正> 1976年7月28日唐山7.8级地震以后,为了进一步研究京、津、唐地震监视预报试验场的地壳深部结构背景,开展了人工地震测深工作,发现中强以上地震多发生在莫霍界面隆起的翼部,而震源又多在中层地壳内低速度层的顶、底部附近;震中多位于华北平原内古生代及更老地层隆起形成的重力高的周边、新生代第四纪断陷盆地的一侧。更多还原

【Abstract】 Combined with the results of gravity, geomagnetic and magnetotelluric prospecting data we carried out a comprehensive analysis of the data obtained from wide angle reflection shot at NW end (SP406.98) of Baigezhuang-Fengnan-Fengning profile into recording stations spreaded to the plain area. The results show the remarkable difference in the crustal structures between Mt. Yanshan and North China plain. The crustal thickness of the Yanshan area is ≥42.0 km and that of North China plain, 30-35 km. The thickness of the low velocity layer underneath the plain is generally 10 km, while it becomes thinner and is divided into several layers in the moutain area.In this paper, we also discussed the geodynamic process of the North China plain sedimentary basin and the genetic mechanism of the Tangshan earthquake.更多还原