郯庐断裂带中南段地壳结构分段特征

本文采用双差地震层析成像方法对郯庐断裂带中南段地壳速度和泊松比结构进行了研究,获得了郯庐断裂带中南段中上地壳介质结构的分段特征.结果表明,郯庐断裂带中南段由南至北可以划分为三段,即庐江以南段、庐江至郯城段及郯城以北段,郯城以北段又可细分为郯城至五莲及五莲以北两个亚段.庐江以南段、郯城以北段地壳介质速度和泊松比呈现相对高...

Segmentation of crustal structure beneath the middle-south segment of Tan-Lu Fault Zone

In this paper, the double-difference seismic tomography method is applied to study the crustal velocity and Poisson's ratio structure of the middle-south segment of the Tan-Lu fault zone, and the segmental characteristics of the middle-upper crustal medium structure are obtained. Results show that the Tan-Lu fault zone can be divided into three parts from south to north according to the characteristics of crustal velocity and Poisson's ratio, namely the southern part of Lujiang, the segment from Lujiang to Tancheng, and the northern part of Tancheng. Furthermore, the northern part of the Tancheng segment can be divided into two secondary segments, which are the Tancheng to Wulian part and the northern part of Wulian. The southern part of the Lujiang and northern part of the Tancheng segments show comparatively high velocity and Poisson's ratio, while the segment from Lujiang to Tancheng shows comparatively low velocity and Poisson's ratio. The velocity and Poisson's ratio in the Tancheng to Wulian secondary segment is significantly higher than the northern part of the Wulian secondary segment. Besides, the boundary of each section is the gradient zone of crustal velocity and Poisson's ratio. In addition, the regional fault structure and moderately strong earthquakes distribute along this gradient zone. The gradient zone of Poisson's ratio is often associated with changing and migration of the deep mantle. This means that the upwelling of deep material along the fault zone may be the dynamic source of tectonic activity and preparation of earthquakes.