多震相走时和波形三维地震成象方法及在祁连山地壳结构研究中的应用

3D Seismic Tomography by Using Traveltime and Waveform of Multiphase and Application to Crustal Structure in Qilianshan Mt.

本文的理论方法是以几何射线理论为基础发展起来的、天然地震走时反演技术及天然地震层析成像技术。它存在着震源函数与介质参数的解耦问题。本研究采取了五种方法来改善反演结果。包括，利用，Pg，Pn等震相增大约束条件；用已有精度较高的人工地震测深结果作速度约柬：用波形反演来修改模型，把诸多物理量开发出来互为约束，以修改后的模型再作反演，使解的稳定性大大提高：采用最优化过程，选择遗传算法。可以进行震源定位，走时反演，波形反演：得到任意深度的速度分布及从地表到Moho面的速度剖面。用于在祁连山地区的结果表明，这些层析剖面对认识大地构造、重大深部事件动力学是很有益的。

A new technique of simultaneous inversion for 3D seismic velocity structure using direct,reflected,and refracted waves is applied to tile Qilianshan Mt. Pg..PmPand Pn arrival times of 32 events with 404 seismic rays are inverted for locations and crustal structure. was inverted. 3-Dseismic crustal velocity tomogrephy, including eight sections from the surface to the Moho,thirteen proiles and the Moho depth distribution was determined..