Based On Gravity And GPS Data To Study Inversion Algorithm Of Activity Parameters Of The Xianshuihe Fault

As an important geological phenomenon closely related to the earthquake,active faults has the close relation with earthquake prediction and seismic risk zoning.By the influence of the Indian plate pushing to the north,the Xianshuihe fault,as a large-scale left-lateral strike-slip active fault in western china,the structure of which is complex,and the fault segmentation's characteristic of which is significant.Besides,the Xianshuihe fault has the characteristic including the earthquake happening frequently,great intensity,serious destructiveness and so on,and is a good place to research earthquake.this paper uses the high precision gravity data and GPS data,combined with the optimal inversion algorithm which includes the particle swarm algorithm,genetic algorithm and the monte carlo method to calculate activity parameters of the Xianshuihe fault,and discusses the relationship between the fault activity characteristics and tectonic movement and earthquake,which plays an important role on the regional earthquake prevention,In this paper,we get the following research:(1)Using the particle swarm algorithm,genetic algorithm,the monte carlo method which combined with the dislocation model and the disclination-dislocation model respectively to invert activity parameters of the single fault by geodetic data which simulated by the single fault,by the result,the paper selects the optimal nonlinear algorithm,Result show: The calculation result of the nonlinear inversion algorithm combining the theory of dislocation and the dislocation model is similar,particle swarm algorithm was compared with genetic algorithm and the monte carlo method has good convergence,strong stability and high precision;genetic algorithm in the second,monte carlo is relatively poor,but on the whole,they all have certain application value.(2)Based on the dislocation model and the dislocation model respectively,this paper uses gravity and GPS data to invert activity parameters of the Xianshuihe fault,Result show: Using the high-precision gravity data to calculate activity parameters of the fault has a similar results with using the GPS data,which extends the field of using geodetic data to research geological;The Xianshuihe fault zone which presents the left-lateral strike-slip movement on the whole gives priority to Sliding characteristics,there shows some characteristics of the rotation in Xianshuihe fault zone,the fault presents more rotation characteristics in the Southeast segment than the northwest segment,and it has a certain transformation tectonic style;The disclination-dislocation model which develops from the classical theory of dislocation is combined with the optimal inversion algorithm to calculate sliding and rotation parameters of the Xianshuihe fault making up the dislocation model in explaining some geodetic observation results(for example: the rotating structure system of Yunnan Tibet? the clockwise tectonic system of Western sichuan region?a smaller level of rotary motion of the Xianshuihe fault).