Recent advances of computing coseismic deformations in theory and applications

This paper reviews the recent advances in computing coseismic deformations,and their contributions to seismology and geodesy. At first,an overview on the history of the dislocation theory development is given in the introduction section. Then,emphasis are given on some new developments through few examples in the following sections,such as the new dislocation theory for a 3D Earth model,a new computing scheme on coseismic deflection change of vertical,the relation of dislocation Love number and the conventional Love numbers,the application of dislocation theory applied in satellite gravity observations,the coseismic deformations observed by GRACE,and a new method to determine dislocation Love numbers by GRACE. Furthermore,some advanced theoretical and cases studies are introduced to illustrate how dislocation theory is important in interpret geodetic data,or invert seismic slip for co- and post-seismic processes,using seismic and geodetic data. Final remarks are given in the last section,with discussions,conclusions,comments on existing problems,and expected methods to solve them.

Static loading and vertical displacement at southern Siberia

Seismic method is usually used for elastic parametric estimation. This is why this method presents dynamic parameters of Earth. Frequency seismic range changes greatly from geodynamic modelling time. Now we have opportunity to use geodesy result for some years for elastic parameters estimation. Static solution from elastic theory may be used for the interpretation of long term results. It presents static elastic parameter. The inverse problem for different types of vertical surface loading on one year period is calculated. Two cases of loading with maximal and minimal area are presented. Results are determined by space geodesy and leveling methods. Current relation between atmospheric pressure and vertical displacements was estimated at the center of Siberian Anti Cyclone with size varied from 2000 km to 3000 kin. Pressure-displacement coefficients （PDC） can be achieved by three years obser- vation （0.997 mm/mbar for NVSK GPS station）. It is used for elastic module study of geology medium with maximum thickness up to 600 km. In the context of elastic model, the modulus of rigidity is estimated to be 113 GPa. Vast expanse of anti-cyclone may relate with rheology of crust and upper mantle. Smaller size of surface loading - local loading is seasonal variation of water reservoir. Annual vertical changes were obtained by leveling near the dam of the reservoir. PDC ratio was 1.15 mm/bar for these places. In elastic theory, the Young modulus E = 80 GPa （Poisson ratio = 0.25, the modulus of rigidity - 32 GPa） was calculated by sixteen years of leveling measurements. This result can effectively be represented for upper crust. Our results were checked by solution for coseismic displacement of Chyia- Altai earthquake （Sep. 27, 2003, M = 7.3）. Coseismic results calculated by static modules agree with experimental coseismic GPS data at 10% level.