Intersection relationship between south segment of Yishu fault zone and surrounding faults derived from remote sensing and gravity multi-source data

This paper collected remote sensing image, digital elevation model and Bouguer gravity data of the south segment of Yishu fault zone (namely the segment between Yishui county and Tancheng county) and its surrounding areas, and studied the regional tectonic landform and deep crustal structural characteristics so as to analyze the intersection relationships between south segment of Yishu fault zone and its surrounding faults. The research results indicate that Mengshan piedmont fault and Cangni fault exhibit obvious tectonic characteristics consisting of river bends, fault steep, gully leaps, fault scarps and fault facets in the remote sensing images. In detail, Mengshan piedmont fault extends eastward to Ju'nan county, while Cangni fault extends eastward to Tancheng. Both the faults crosscut Yishu fault zone on the geomorphology; in the gravity detail field, the two faults form a gravitational gradient zone on different scales, which extend down to the lower crust and appear as deep faults. Moreover, the lineaments intersect with Yishu fault zone and contribute to the distorted, broken, beaded gravity anomalies, confirming that Yishu fault zone has been cut through in the deep crust. Therefore, a great uniformity between the interpretation results of two faults in remote sensing and gravity field suggests that the two faults all crosscut south segment of Yishu fault zone in landform and deep crust, so that the segmentation characteristics occur. In addition, there is a new fault developed near Linshu county, namely Xiangzhuang-Shaling fault. The fault is higher in north and lower in south, along which the rivers left-hand bend synchronously, and in the 1-to-3-order gravity field there are linear gradient zones, so it is speculated that the fault extends down to the middle crust, and crosscuts the eastern graben of Yishu fault zone near Linshu county, but not extends to the western graben.