Abstract: In this paper,the structure of twodimensional crustmantle velocity and ratio of wave velocity γ is obtained by interpreting S wave data of depth seismic sounding profile alone Wenan—Yuxian—Cahayouzhongqi. The upper crust and middle crust is mainly made of granite, and all is brittle, the γ value for ratio of velocity is about 1.72 for the lower crust it is 1.78; and for the top of upper mantle it is 1.82. The result shows that the lower crust and the top of upper mantle have plastic features. In terms of the features of wave sets and lateral changes of γ, a few deep faults are inferred in this region. Combining with seismicity of this region, it is suggested that the occurrence of earthquakes is related to the structure as well as the character of rocks.

Key words: Seismic sounding, Ratio of wave velocity, Structure of velocity, Seismicity

摘要： 通过对文安—蔚县—察哈尔右翼中旗深地震测深剖面S波资料的处理解释,获得本区二维壳幔速度结构和波速比结构。该区的上、中地壳主要由花岗岩组成,整体呈脆性,其速度比γ值为1.72左右;下地壳的γ值一般为1.78;上地幔顶部的γ值在1.82左右,表明下地壳与上地幔顶部整体呈塑性的特征。根据波组及γ值横向变化特征,推断了该区的几条深大断裂,结合本地区的地震活动,推测地震的孕育发生不仅与构造相关,而且与该区的岩石性质有关。

关键词: 地震测深, 波速比, 速度结构, 地震活动