Objective Situated between the Ordos Block and the Qinling Orogenic Belt, the Weihe Basin features intense tectonic activity. More than ten major active faults including the Weihe Fault and the northern margin fault of the Qinling Mountains, as well as numerous tectonic lineaments, are developed within the basin, resulting in prominent seismic hazard risks. This paper aims to systematically investigate the distribution of lineaments and their correlation with seismic activity in the study area.
Methods Based on ALOS PALSAR DEM data with a resolution of 12.5 m, this study uses an edge detection algorithm to automatically extract tectonic lineaments in the Weihe Basin. Hydrological analysis is employed to filter out extraction artifacts caused by exogenic landforms, such as river terraces and gully systems. Focusing on earthquakes of magnitude 3 or higher, the study utilizes the weighted information content analysis method to integrate data on geogravity anomalies, bedrock lithology, and secondary structural unit data to establish a seismic risk assessment model.
Results ①Tectonic lineaments can be effectively extracted using DEM data. After post−processing to eliminate interferences, the obtained 1232 lineaments show consistent spatial distribution with known faults; ②The information value of tectonic lineaments for seismic events is 0.6 with a weight of 0.57, and 90.91% of earthquake epicenters are distributed within 4000 meters of lineaments; ③Medium− and high−risk zones account for 33.73% of the total study area and host 77.27% of recorded earthquakes, which are mainly distributed along lineaments.
Conclusions Seismic activity in the Weihe Basin is predominantly controlled by tectonic lineaments. The seismic risk index map generated via the weighted information model can effectively reflect the regional probability of earthquake occurrence, providing geological support for disaster prevention and mitigation.
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