Study Of Dynamical Inertial Weight And Dimension Mutation PSO Algorithm And The Fault 3D Disclination Model And Its Applications

The theory of geodetic inversion has been widely used in the domain of geosciences, including crustal deformation, the regional velocity construction, fault active analysis, the determination of higher seismic region and so on. The geodetic inversion, to some great measure, consists of physical model and inversion method, the physical model which can depict a geological event is the premise to understand the nature of this event; By geodetic inversion we can obtain the condition of a geological event from the observation data indirectly, which allows us to study its changing process and master its changing laws, finally, some predictions can been made properly. In this paper, based on the classical particle swarm optimization and disclination theory, our research focus on the study of the improved PSO algorithm and disclination-dislocation model and their applications in the investigation of fault movement.In this paper, the primary research work including:(1)In order to obtain the better estimates, some linear and nonlinear weight factors have been proposed to overcome the weaken convergence of the classical PSO algorithm, however, the convergence speed is still slow although the solution, to some extent, has been improved. Thus, in order to enhance the convergence of the parameter estimation and improve the speed to convergence, based on the chaotic mutation ideas, a new particle swarm optimization(PSO) algorithm with dimension diversity and dynamical inertial weight vector(DDMWPSO) is brought forward, we can achieve better estimates through weight factor adaptive adjustment in different dimensions. Finally, simulated calculations are carried out to test its stability and effectiveness.(2)In order to further validate the stability and effectiveness of DDMWPSO, this method is introduced to make an inversion for fault slip rate and construct crustal movement velocity field. The fault slip rate of the mainly three faults in northeastern margin of Tibetan Plateau, including Qilianshan, Haiyuan and Liupanshan fault, are achieved by the DDMWPSO algorithm from the GPS data, which have a better consistence with geological and other results. Furthermore, combined with Euler vector, the crustal movement velocity field of the northeastern margin of Tibetan Plateau is constructed by this improved algorithm, some complex procedures in the process of solving crustal movement model, to some extent, can be overcome. What’s more, the result shares the similar precision with results computed by the Least Square Collocation.(3)For the case of fault rotation, the formulas to express surface deformation caused by fault three-dimensional rotation in elastic homogeneous medium are derived; the effect to surface displacements caused by fault rotation due to different dip and depth is analyzed. We can come to the conclusion that: the surface displacement diminishes with the increment of fault depth and has a different responses to the fault dip angle; the modeled velocity values are numerically approachable when the fault rotates the same angle in different ways, the space distribution of vertical deformation is closely related to the rotation ways; the surface deformation caused by 3D rotation has some distinctions with sliding result in numerical, but harbors the same magnitude. However, the deformation due to fault sliding is more extensive than rotation in terms of the spatial range.(4)To begin with, the strain character of the eastern Tibetan Plateau before Wenchuan Ms8.0 earthquake is calculated by multiquadric function method from the GPS data. The strain along the Longmenshan fault accumulated rapidly before the Wenchuan earthquake, and the middle segment of Longmenshan fault was in locking but with an increasingly accumulated strain. Furthermore, we find out and analyze the phenomenon that may be related to the fault rotation, based on the coseismic observation data of GPS, the fault movement in the process of Wenchuan Ms8.0 earthquake is calculated by DDMWPSO algorithm and disclination-dislocation model proposed in this paper, results inform us that the disclination-dislocation model is such more suitable to present the listric geometric structure that more properly to analysis the co-seismic fault movement than the traditional plane sub-fault model which is tremendous used.