Based On GPS Observational Data To Research On Characteristics Of Regional Crustal Deformation And Strain

GPS are widely used for its advantages of all-weather, high-precision and real-time in thefields of crustal deformation, geodynamics, seismology and so on. Especially with theintensive construction of the permanent global continuous GPS observation stations andimprovement of accuracy in GPS data processing, GPS can monitor more precisely on globalplate motions, regional crustal deformation of active blocks and fracture state of motion,which can describe the law of the crust surface displacement field’s change over time moreaccurately. Based on this, through constructing a high-precision reasonable mathematical andphysical model of surface deformation and regional intrinsic deformation based on thegeological, geophysical and other data, further regional crustal deformation stress and strainparameters can be deduced, which can help to grasp the internal mechanism of the regionalcrustal deformation characteristics deeply. Therefore, based on high-precision crustaldeformation, mathematical and physical models of surface deformation and crustal stress andstrain parameters are researched deeply and established according to regional geologicalstructure characteristics. And then, different regions today crustal deformation-straincharacteristics are concluded as followed:Firstly, illustrated by the case of the northeastern margin of the Qinghai-Tibet block inwhich tectonic activity is intensely, a multi-faceted function fitting model is established whichdescribes the regional crustal deformation and crustal strain parameters. At the same time,maximum shear strain of crust in this region, the surface expansion and the main strainparameters of the distribution characteristics are deduced. And then, intrinsic relationship oftectonic activity about the regional seismic and so on are investigated and some valuablereferences are drawn.Secondly, based on elasticity theory, active blocks strain model of two-dimensionalboundary in Qinghai-Tibet block northeastern margin are researched and the established.Strain characteristic parameters and distribution patterns of bulks of different activities’characteristics within the study area are deduced. The result is compared with the one usingmulti-faceted function fitting and differences of the two types of methods for solving resultsare analyzed. Finally, because the crust has non-continuous deformation characteristics, illustrated bythe case of famous Xi’an ground fissures, the three-dimensional boundary element model ofground fissure activities and surface activities is established and the intrinsic relationshipbetween ground fissure activities and surface deformation under regional tectonic stress fieldis deduced through forward modeling. Illustrated by the case of We-chuan earthquake,three-dimensional structural model of coseismal activities and surface deformation isestablished. The coseismal fault rupture to ward the surface, the tendency to slip and thedistribution characteristics are obtained through inverse modeling and the result is consistentcompared with the results of geology to some extent.