Source Rupture Process Inversion Of Teleseisemic Body-wave Based On Direct Waveform Inversion

Seismic source research is one of the main orientation of seismology, whichcan help mankind to know the mechanism of earthquake and the nature of source.Seismologists began to study seismic source in1910, but it was not until1935thatseismologists have just introduced the physical quantities——Richter Scale. Fromthe view of the quantitative description, from magnitude to the seismic momenttensor, and then to the source rupture process, it has taken decades of development.The so-called earthquake rupture process, refers to the rupture behavior of the faultzone in the diffusion process, described in two dimensions of time and space. In thestudy of rupture process, we can get lots of source parameters, including duration,seismic moment magnitude, fault spatial scale, spatio-temporal distribution of slip,and so on.Based on the theory of direct waveform inversion method, this paper considersthe case of slip angle variable. Meanwhile, based on the the teleseismic body-waveinversion procedure proposed by Kikuchi and Kanamori, this paper modifies it toachieve the inversion of the Japan Tohoku earthquake March11,2011. The mainresearch contents and results are as follows:(1) Combining the domestic and foreign research situation, generalize sourcerupture process inversion comprehensively. Starting from the displacementrepresentation theorem, this paper derives the basic equation for rupture processinversion, constructs the general form of the direct waveform inversion method, anddiscusses the influence of different materials to the resolution of inversion results.(2) Based predecessors' work, optimization and improvement of the teleseismicbody wave inversion procedure is made, the theoretical basis of the program isdiscussed thorough, and the program module, algorithm and parameters is illustratedin details.(3) By teleseismic body-wave procedure, the Japan Tohoku earthquake isimaged and this practical inversion can verify the correctness and applicability.After the discussion of different case of parameters setting, the results such asearthquake source time function, slip distribution, rupture diffusion process can beobtained and then comparison between them and other scholar's research results is made.