The Deep Material Structure of the Xiaojiang Fault and Its Surrounding Areas: Based on Magnetic Anomaly Model and Magnetotelluric Data

The Xiaojiang fault is a large active fault and a strong earthquake zone with strong tectonic motion. Located near the middle zone of the Emeishan Large Igneous Province and as the southeastern boundary of the Tibetan Plateau, it plays an indispensable role in the lateral escape mechanism of plateau material and regional tectonic evolution. Previous studies have shown that the Xiaojiang fault has low velocity, high Poisson's ratio, low electrical resistivity, high heat flow, and strong attenuation, while the Emeishan Large Igneous Province inner zone has high velocity, high electrical resistivity, and low heat flow. The location and morphology of channel flow are still inconclusive. The magnetic susceptibility structure obtained from regional magnetic anomalies can directly reveal the deep magnetic structure, while the thermal structure is direct evidence to support the material transport. This report aims to study the thermal structure of the Xiaojiang fault and its surrounding areas. Combined with the previous research to identify heat flow channels, determine the possible places of crust-mantle material exchange, clarify the material transport mechanism, and explore the regional seismic hazard. This report aims to provide a diversified supplement to the deep material structure and material transport mechanism in this region, and to understand the deeper geoscientific significance of the Xiaojiang fault and its surrounding area.