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The Danjiangkou Reservoir is the starting point of the Middle Route of South-to-North Water Transfer Project. The stability of the reservoir is critical to the safety of the surrounding residents. According to statistics, in recent years, with the increase of the Danjiangkou Reservoir's water storage capacity, earthquakes' frequency has gradually increased. It is of considerable significance to discuss the geological mechanism behind the phenomenon. In this paper, a case study of the Songwan area, northwest of the Danjiangkou Reservoir, was introduced. We tried to comprehensively analyze the main factors that caused high earthquake occurrences in the area from remote sensing and aeromagnetic survey data. The Landsat8 multispectral images were used to interpret and analyze the regional faults information. The results showed that the seismic concentration area is located at the intersection of a series of northwest-direction linear faults and a north-east linear fault, showing signs of circular structure around. In addition, aeromagnetic survey data reveals that there are large-scale and gentle magnetic anomalies in the seismic concentration area. It is speculated that the anomaly is caused by the underlying intermediate acid intrusion, which is consistent with the result of remote sensing interpretation. Using optical remote sensing and aeromagnetic survey technology, we analyzed the geological conditions and the causes of frequent earthquakes in the Songwan area from the perspective of regional structure and lithology and provide a valuable reference for the study of seismic mechanisms and safety precautions.
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