天水地震区综合地球物理剖面的建立与壳幔结构

根据人工地震、重力、大地电磁和地热资料，在天水地震区建立了二个综合地球物理剖面．对这两个剖面进行了分析，研究了该地区的壳幔结构．结果表明，沿西秦岭北缘断裂带，地壳变薄，低速层、低密层和低阻层同步出现，同时在断裂带附近形成了宽几十到上百公里的相变过渡带，其影响深度可达上地幔．

ESTABLISHMENT OF COMPREHENSIVE GEOPHYSICAL SECTION AND CRUST-MANTLE STRUCTURE IN TIANSHUI EARTHQUAKE AREA

Based on the data of deep seismic sounding,gravity,magnetotelluric sounding and geotherm,two comprehensive geophysical sections are established in Tianshui earthquake area.Analysing the two sections,crust mantle structure in the Tianshui area are studied.The results show that crustal thickness along fault zone in the north edge of western Qinling is thin,and low velocity layer,low density layer and low resistivity layer synchronously exist there.The facies change transition zones of tens to a hundred kilometers in width and up to upper mantle in depth exist on the both sides of the fault zone,which means that depth of the fault zone possibly is up to upper mantle.