灵台—阿木去乎剖面地壳速度结构

THE CRUSTAL VELOCITY STRUCTURE IN LINGTAI-AMUQUHU PROFILE

在Ⅰ测线观测资料的基础上,本文结合测区特点给出了高程校正及沉积层校正方法,利用反射波与莫霍面折射波运动学特性进行一维、二维地壳结构的正、反演计算,获得了自甘肃夏河至灵台460公里范围内的分层地壳结构,认为西部地壳厚度约51公里,东部仅为44公里,已属鄂尔多斯地台区结构,与地槽区的分界线大致对应地表陇县固关镇。武山与张家川之间在15—20公里深处存在低速层。结合地震波的动力学特性,可判定本测线通过的超壳断层有鄂尔多斯西缘—六盘山断裂、西秦岭北缘断裂和武山南北向断裂。

Using the recording data of the lengthwise profile( from Lingtai to Amquhu)and processing corrected traveltime depend on the station's height and the loessal thickness, the 1-D and 2-D crustal velocity structure in the area was obtained. Along the line in the west the crustal thickness is about 51 km and in the east only 44 km. The eastern of profile is the structure of Erduos Platform style. Guguan town is located in the boundary between geosyncline area and platform area. There is a P-wave lower velocity layer (LVL) which embeds in 15-20 km between Wushan and Zhangjiachuan. Combining the seismic wave's dynamical parameters of observed data, some over-Moho faults, containing the Western Fringe Fault of Erduos Platform-Liupanshan Mountain, the Northern Fringe Fault of western segment of Qinling Mountain and Wushan Fault with N-S direction, have been determined,