Applied research on predicting strong earthquake risk areas in western Yunnan based on Curie-point depth and seismogenic characteristics
摘要
Research on strong earthquake analysis based on inverted Curie-point depth has been successfully applied in multiple regions across the world. By sorting out the existing research achievements in western Yunnan, this study finds that no relevant work has yet been conducted to invert the Curie-point depth via the fractal method using aeromagnetic data in this region. Through the targeted setting of relevant parameters in the inversion process, the Curie-point depth obtained by inversion in this study is more consistent with the basic survey results of regional geothermal conditions. Based on the inversion results of Curie-point depth, this study integrates two core sets of indicators for comprehensive analysis: one is the regional geological characteristic that strong earthquakes generally occur near Curie-point depth gradient zones and fault zones, and tend to be distributed close to Curie-point uplift areas; the other is the precursor criteria of strong earthquakes in the study area, namely a quiescent period within a 150 km range before earthquakes of MS≥5, a significant increase in the frequency of MS≥4 seismic activities, and zonal clustering near the epicenter prior to earthquakes of MS≥6.8. In accordance with the seismogenic characteristics of strong earthquakes in the study area, a set of forecast method for seismogenic hazard zones that can determine relatively accurate potential risk ranges is developed, and empirical application of this method is carried out within the research region. Compared with previous relevant studies, this method is more conducive to practical application due to its advantages of convenient data acquisition and easily quantifiable operation procedures..