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在人工地震测深工作尚不能大面积开展的地区,利用重力资料推断解释地壳厚度的平面分布,来研究地震孕育和矿藏生成的深部环境,是一项既经济又具有科学性的工作。为了弥补采用平均场、向上解析延拓和频率域滤波等方法以及采用二维计算方法的不足,本文依据豫鲁皖部分地区(东经114°～116.5°,北纬32.5°～39.5°)的重力资料和浅部地质、物探资料,采用三维正演方法分别计算浅部各层密度界面产生的重力异常,并从布格重力异常中消除其影响,得到剩余深部重力异常;然后采用多次正演计算和异常曲面逼近的反演方法,求得该区地壳厚度的最佳分布。用重力反演方法得到的地壳厚度,2倍均误差小于1公里。与人工地震测深剖面对比,两者的起伏形态基本一致,相差一般不超过2公里。本文最后指出了震中位置相石油、天然气与地壳厚度的空间对应关系,并作了初步分析。
It is an economical and scientific task to study the in-depth distribution of the crust thickness by gravity data in order to study the deep environment of earthquake breeding and mineral deposits. In order to make up for the disadvantages of using average field, upward resolution and frequency domain filtering, and using two-dimensional calculation methods, based on the gravity data of parts of Henan, Shandong and Anhui Provinces (longitude 114 ° -116.5 ° longitude and latitude 32.5 ° -39.5 ° north latitude) And shallow geology and geophysical prospecting data, the gravity anomalies produced by the density interface of the shallow layers are calculated respectively by the three-dimensional forward modeling method, and the residual gravity anomalies are eliminated from the Bouguer gravity anomalies. Then, multiple forward anomalies are calculated And the inversion of anomalous surface approximation, the optimal distribution of crustal thickness in this area is obtained. The crustal thickness obtained by gravity inversion method is less than 1 km with 2 times the average error. Compared with the artificial seismic sounding profiles, the undulations of the two are basically the same, the difference is generally not more than 2 km. At the end of this article, we point out the spatial correspondence between the epicenter oil, gas and crustal thickness, and make a preliminary analysis.