Three-dimension Slip Velocity Of Fault Inversion With Ant Colony Algorithm

Inversing the slip rate of fault and such as dynamic parameters with geodetic data, thus through the ground-based observation of surface distortion to understand the geodynamic process of slip rate of fault to discussion the relationship between the crustal movement and earthquake, forecasting the earthquake and the geological disaster which has important scientific significance.In this paper, It is combined the dislocation model with three kinds of geodetic data (GPS, leveling, gravity changes) and introduced a new optimization algorithm-ant colony algorithm for inversing three-dimension slip velocity, constructed the basic idea of inversing fault parameters with ant colony algorithm base on dislocation model, then combined with three faults named Qilian Mountains fault, Longshou Mountains fault, Huangcheng-Ta'er zhuang fault in Hexi region to make a specific inversion study analysis. The main works and conclusions are summarized as follows:1 .The research of present situation and the theories of geodesy inversion, dislocation model, ant colony algorithm are introduced in detail in this paper, these provide a theoretical foundation in doing research work.2.Given the slip rate of fault inversion calculation model (objective function) with single data (GPS, leveling, gravity changes), Treats the inversion parameter in view of the characteristic of fault, the search space using the discrete method to its discrete is discussed, And the use of ant colony algorithm for the classic TSP problem with the similarity in the problem of fault slip parameters inversion, then make the improvement in the ant colony algorithm, So as to established the basic method based on ant colony algorithm inversion of fault parameters in the dislocation pattern.3.Using the dislocation theory obtained the surface variation of gravity value through pure strike-slip fault, added with a certain degree of artificial disturbance error simulated the real measured values of gravity variation on this calculation result, The method which proposed based on this paper using the ant colony algorithm inversion computation the three-dimensional slip velocity of the faults, Simultaneously also carries on the traditional inversion method-Monte Carlo, and then compared with effects of two algorithm inversion, The results showed that: the ant colony algorithm combined the dislocation model to have good feasibility and the validity in the fault parameters inversion, and it is superior to the Monte Carlo method inversion results.4.Hexi area is located at the northeastern margin of the Qinghai-Tibet block, Which is strongest, the highest frequency of seismic activity, one of the regions biggest strength in the Chinese continental crust, selected three fault still happen in a active named the northern margin of Qilian Mountains fault, Longshou Mountains fault, Huangcheng-Ta'er zhuang fault in this area, Take the application example with three fault, According to geological data determined geometric parameters of fault, With observation of GPS data during the year 1999 to 2001, leveling data during the year 1995 to 2000 and gravity variation data during the year 2002 to 2003, Using the ant colony algorithm union dislocation model to inverse three-dimensional slip velocity of three faults separately, The results showed the single data ant colony algorithm inversion results to be consistent in the fault kinetic property with the geotectonic background, Which has certain difference in the value of three-dimensional slip velocity with the geology method obtained results.5. Ant colony algorithm was researched in two types of data in the application of joint inversion the slip rate of fault. Through the use of two programs: the conventional decided the weight ratio and took into consideration the relative weight ratio to carry on the joint inversion computation separately the above three faults, And conducted a comparative analysis of the effect of two kinds of plan's inversion, Quantitative description in the rough under a priori information, The conventional weight ratio method make the value of X existence the larger subjectivity, The deviation of inversion results is larger, Took into consideration the relative weight ratio factor which carried on the inversion make different kinds of observational data matched to be more reasonable and thus obtain the relatively satisfactory results.