Study Of Numerical Simulation In Earthquake Deformation And Fault Activity Based On D-InSAR

With the development of earth sciences, numerical simulation methods increasingly used in earthquake mechanism of the causes and precursors, as well as seismic deformation research fields and so on. As the complexity of geological structure, the heterogeneity of earth medium, the diversity of physical properties of rocks, whether or not the precise result of numerical simulation are closely related with the crust model, the seismogenic fault models, constraints, and the medium parameters, which gives difficulties to the evolution of seismic deformation and stress. To solve this problem, researchers have begun working more advanced simulation methods, gradually raised effective crust medium model and more advanced computational methods, moreover these models and methods are used increasing in seismic deformation field, seismogenic fault attitude, the dynamic evolution and migration of the tectonic stress field.The main research work and contributions are as follows:1) This paper introduced the application of numerical simulation theoretical model history and present situation of the study in Geophysics and Seismology. By analyzing and summarizing the limitations in the traditional crustal models, we presented the necessary of the research of viscoelastic half space model, and applicability in monitoring crustal deformation.2) Suppose that there are four kinds of crustal models:(1) elastic half-space without gravity effect; (2)elastic-gravitational half-space; (3)layered viscoelastic half-space without gravity effect; (4)layered viscoelastic-gravitational half-space with gravity effect; Based on these crustal models, we carry out the coseismic and post-seismic response of different dislocations, including normal fault, reverse fault and strike-slip fault, and the finally we got the role of various factors which played in different crustal models in the different seismogenic fault mode. After that, given layered viscoelastic-gravitational half-space, we obtained the deformation and stress distribution after earthquake, post-seismic deformation, elevation, and local geoid changes.3) In order to study the practical earthquakes, we selected the 2008 Dumxung earthquake and the 2010 Yushu earthquake. The Dumxung earthquake seismogenic fault was normal faulting with a little of right-lateral strike slipping. This earthquake led to a subsidence of at least 0.3m at the epicenter of Yangyi basin, and the average subsidence rate is 5-6 mm/a; Then compared the D-InSAR observational results with the simulation results, the residual is 0.028m, this verified the reliability of the numerical simulation; The Yushu earthquake showed the characteristics of pure shear ruptures, kinematics properties for left-lateral strike-slip, and dislocation was up to 0.5m, the maximum slip rate of surface horizontal displacement 0.0081 m/a, a seismogenic fault slip of the dynamic characteristics; reflect the characteristics of pure shear ruptures, kinematics properties for left-lateral strike-slip; The vertical displacement deformation field presented four-quadrant distribution, and the sharpest change in the northeast of the fault, about 3.5mm/a, the activity of the fault after the earthquake remained primarily in a left-lateral strike-slip trend.