约束走时层析成像  

Restrained travel time tomography

作　　者：张文生[1] 何樵登[1] 

机构地区：[1]长春地质学院

出　　处：《石油地球物理勘探》1997年第1期68-74,共7页Oil Geophysical Prospecting

摘　　要：地震层析成像技术是反演地下速度结构的一种重要方法。与医学CT不同，一般地震波射线对目的区覆盖不均匀，所获得的数据不充分。在这种情况下，若初始猜测不准，常规的成像方法，如阻尼最小二乘法、ART法等难以获得理想效果。为此，我们研究了带有约束条件的成像方法。这种方法是通过加入不等式约束条件后再求解最小二乘问题的。文中得出了这种约束条件下的最优化问题的解。处理该问题的方法也适用于其它非线性约束最优化问题。最后的数值结果及解的评价证明了该方法在处理射线数据不足情况下的有效性及优越性，且有一定的抗噪能力。Seismic tomography is an important technique for estimating subsurface veloci-ty structure. Unlike medical CT, seismic tomography often uses less enough databecause seismic rays fail to uniformly cover the objective area. If a poor initial mod-el is chosen in such case, conventional tomography methods, such as damped leastsquare method, algebraic reconstructioh technique etc. can hardly produce satisfac-tory results. To cope with the problem, we put forward a restrained tomographymethod, which s0lves least square problem after an inequality restriction is given.The solution of optimized problem under the restriction is deduced in the article.The idea of solving this prob1em is also app1icable to solving other non1inear re-strained optimization problems. The final numerical result and the relevant evalua-tion prove this method effective and superior in the case 0f less enough data. Whatis more, the method has certain noise resistance.

关 键 词：地震数据处理 反演 CT 约束 速度结构 

分 类 号：P631.443[天文地球—地质矿产勘探]