Structural Features Of Luhuatai Fault Based On Integrated Geophysical Exploration Methods

This paper takes the reed Luhuatai fault in the Yinchuan Basin as the research object.Based on the previous studies,it mainly uses the magnetotelluric sounding method,the audio magnetotelluric sounding method,the high-frequency magnetotelluric sounding method and the soil-Rn testing method.The geophysical methods were used to detect and explain the detailed location of the Luhuatai fault,the deep structural form,and the spatial distribution of the shallow partial branch fault.The dynamic mechanism and activity of the fault formation in the Luhuatai fault were discussed in combination with the regional tectonic dynamics background analysis.Sex.Provide geological data reference for the development planning of Yinchuan City and Shizuishan City in Ningxia and the prevention and forecasting of geological disasters such as earthquakes.This paper has achieved the following results:1.According to the interpretation results obtained by this comprehensive geophysical exploration method,from the deep structural features,the Luhuatai fault hidden in the basin extends downwards for about 12 km in the northern part of the basin,and meets on the Helan Mountain fault.The Luhuatai fault in the southern part of the basin cuts the Yinchuan fault with a small dip angle,and the 6km depth meets the Yellow River fault.From the shallow structural features,five comprehensively interpreted secondary concealed faults are distributed on the plane in the southern part of the fault.Parallel distribution.These secondary fractures tend to be east,the production is steep,and the extension is large.The individual fractures extend about300 m in the vertical direction and intersect with the main fault.2.Through the geomagnetic evidence of the deep structural features and tectonic evolution of the Yinchuan Basin,it is preliminarily believed that the Luhuatai fault is mainly a fault zone composed of tensile normal faults formed by tensile stress generated by the upper mantle.3.Through the analysis of soil-Rn test results,it is considered that the activity of the southern section of the Luhuatai fault is relatively uniform;while the northern section is relatively weaker than the south of the Forward farm.