| On the basis of comprehensive study and acquaintance with research on earthquake rupture process, starting with seismic source representation theorem, we derived the fundamental principles of inversion research of earthquake tempo-spatial rupture process. Also, we summarized conventional constraint conditions, the retrieve method of apparent source time functions (ASTFs) and some inversion methods in the research of earthquake rupture process. Furthermore, we proposed two new methods for research of earthquake rupture process:equal-moment back-projection method and sub-events imaging method.Firstly, to improve the temporal and spatial resolutions of rupture processes of regional (moderate and strong) earthquakes, with the aid of 2013 LuShan Mw6.6 earthquake and 2014 KangDing Mw6.3 and Mw5.8 earthquake doublet, we investigated the effects of ASTFs retrieving from the regional waveforms with the empirical Green’s functions technique and analyzing and inversing of moderate and strong earthquakes spatial-temporal rupture processes with ASTFs.Secondly, to retrieve spatial-temporal information of source rupture quickly and then used for earthquake emergency response and earthquake early warning, we proposed equal-moment back-projection method for imaging the low frequency spatial-temporal characteristics of source rupture process. We tested the feasibility of new developed equal-moment back-projection method through multiple numerical experiments. To test its practicability, we used this new method to imaging the spatial-temporal characteristics of source rupture processes of 2014 KangDing earthquake doublet (Mw6.3 and Mw5.8). The results suggested that this new developed method was effective for retrieving the low frequency characteristics of source rupture process, and it was the supplement for traditional high-frequency back-projection method.Then, based on the principle of equal-moment back-projection method and inspired by the traditional inversion methods for source rupture process, we developed sub-events imaging method to imagine the spatial-temporal process of source rupture directly. Compared to traditional inversion method of source rupture process, new developed sub-events imaging method didn’t need prior information of maximum rupture speed and rise time of sub-faults. So, this new method allowed variation of rupture speed and repeated rupture of sub-faults when imaging the spatial-temporal process of source rupture. The same as before, we tested the feasibility of new developed sub-events imaging method through numerical experiments. And to test its practicability, we used this new method to imaging the spatial-temporal characteristics of source rupture processes of 2014 KangDing earthquake doublet (Mw6.3 and Mw5.8). The results suggested that the new developed sub-events imaging method could get the major information of earthquake spatial-temporal rupture process, but the scale was a little small than the results from apparent source time functions inversion.Lastly, we used multiple methods for research of earthquake tempo-spatial rupture process to study the Nepal Mw7.8 earthquakes and its large aftershocks that occurred in April,2015, and compared the advantages and disadvantages of these methods in revealing the information of earthquake rupture process. Specifically, at first, we used P-ASTFs to analyze the rupture directions of the main-shock and its larger aftershocks, and inversed the tempo-spatial rupture processes of these larger events jointly with P waveforms and InSAR data; then, we used equal-moment back-projection method and sub-events imaging method to analyze the tempo-spatial characteristics of low frequency energy migration and rupture processes of these events and discussed these results at last. To the Mw7.8 mainshock M, the joint inversion result showed that this event ruptured unilaterally, expanded about 150 km along SSE direction, and about 70km to the deep along dip direction, it was consistent with the results of equal-moment back-projection method and sub-events imaging method, but the size of expanding was a little larger from the joint inversion result, maybe it was due to a little larger rupture velocity (3 km/s) for the joint inversion; to the Mw6.7 strong aftershock A2, the results from inversion method and equal-moment back-projection method and sub-events imaging method were consistent, they suggested that this event extended to the deep along dip direction, and the searched rupture velocity from inversion method was 4 km/s, it was also consistent with the rupture velocity of 3.9 km/s from the equal-moment back-projection method, they all suggested that this event maybe a super-shear rupture event; to the Mw7.3 strong aftershock A3, as a result of combination of InSAR data, the joint inversion result suggested that this event ruptured toward south-southeast direction, it was a little different from the results of equal-moment back-projection method and sub-events imaging method that suggested this event ruptured toward southwest-south direction, and the direct imaging results showed that this event ruptured slowly.In short, this thesis summarized the development history of research of earthquake rupture process and derived existed methods; then, we proposed two new methods and interpreted the practicability and the advantages and disadvantages of new methods through necessary numerical experiments and applications in earthquakes. |
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