活动断层运动的重力场反演

ON THE MOVEMENTS OF ACTIVE FAULTS BY THE INVERSION OF GRAVITY DATA

阐述了断层错动引起地表重力变化的基本原理 ,给出了弹性半无限空间点源位错到矩形位错引起的重力变化的基本解析式 ,并将结论推广到多个断层。介绍了利用重力变化反演断层运动的基本思路。以滇西实验场作为应用实例 ,对 1996年 2月丽江 7.1级地震发生前后场区内的活动断层运动进行了演算 ,给出了断层位移解 ,并与已有资料相比较 ,结果基本一致 ,但误差分析结果表明本文位错模型还有待于改善。

The principle of gravity changes caused by fault movements is explained systematically. The analytical expressions of gravity changes produced by the rectangle fault dislocation are given. Then the formula of gravity changes caused by several faults dislocation is derived .The method of inversion fault movements from gravity changes is explained and applied to the West Yunnan Test Field. The displacements of faults in the field before and after the Lijiang earthquake(Ms=7.1) is computed. Some results are in agreement with that of the existing documents, some are not prepared as the lack of data. Through the error analysis it is pointed out that the model should be more complicated.\;