各向异性介质中利用跨孔qP波和qSV波走时的统计法成像

STATISTICAL TOMOGRAPHY IN ANISOTROPIC MEDIA BY USING CROSSHOLE TRAVELTIMES OF qP WAVE AND qSV WAVE

跨孔层析成像通常在各向同性条件下进行,地壳中存在着广泛的各向异性,考虑各向异性介质的成像具有重要的理论意义和实际价值,本文以各向异性介质的走时扰动理论为基础,进行了qP波和qSV波跨孔走时的联合成像,与各向同性情形相比,各向异性介质的成像是一个更为病态的问题。本文首次将正则化方法与统计检验理论相结合,提出了统计法跨孔成像。数值模拟结果表明,此法具有精度良好、计算稳定和较少受初始模型限制的优点,并可进一步推广到其他地球物理反问题求解。

Crosshole tomography is usually carried out under the condition of isotropy. However, anisotropy exists in crust extensively. Considering the problem of aninsotrpic tomography has important theoretical and practical value. In the paper, based on the anisotropic traveltime disturbance theory, crosshole tomography by using qP- and qSV-wave traveltimes is studied. Compared with isotropic tomography, the anisotropic tomography is a more ill-posed problem. Here, combining regularization method and stastistical hypothesis testing theory, we proposed statistical crosshole tomography method and solve the problem effectively. Numerical results show the method has the advantages of ideal precision, stable calculation and less influence confined by initial models, moreover, it can be extended to solve other geophysical inverse problems.