中强地震震源的破裂过程

With the large developments of the seismic sources theory, computing technologies and survey instruments, we can model and rebuild the rupture process of earthquakes more realistically. On which earthquake sources' properties and tectonic activities law are realized more clearly. The researches in this domain have been done in this paper as follows. Based on the generalized ray method, expressions for displacement on the surface of a half-space due to an arbitrary oriented shear and tensile dislocation are also obtained. Kinematically, fault-normal motion is equivalent to tensile faulting. There is some evidence that such motion occurs in many earthquakes. The expressions for static displacements on the surface of a layered half-space due to static point moment tensor source are given in terms of the generalized reflection and transmission coefficient matrix method. The validity and precision of the new method is illustrated by comparing the consistency of our results with the analytical solution given by Okada's code employing same point source and homogenous half-space model. The computed vertical ground displacement using the moment tensor solution of the Lanchang_Gengma earthquake displays considerable difference with that of a double couple component .The effect of a soft layer at the top of the homogenous half-space on a shallow normal-faulting earthquake is also analyzed. Our results show that more seismic information would be obtained utilizing seismic moment tensor source and layered half-space model. The rupture process of 1999 Chi-Chi, Taiwan, earthquake investigated by using co-seismic surface displacement GPS observations and far field P-wave records. In according to the tectonic analysis and distributions of aftershock, we introduce a three-segment bending fault planes into our model. Both elastic half-space models and layered-earth models to invert the distribution of co-seismic slip along the Chi-Chi earthquake rupture. The results indicate that the shear slip model can not fit horizontal and vertical co-seismic displacements together, unless we add the fault-normal motion (tensile component) in inversions. And then, the Chi Chi earthquake rupture process was obtained by inversion using the seismograms and GPS observations. Fault normal motions determined by inversion, concentrate on the shallow northern bending fault from Fengyuan to Shuangji where the surface earthquake ruptures reveal more complexity and the developed flexural slip folding structures than the other portions of the rupture zone For understanding the perturbation of surface displacements caused by near-surface complex structures, We have taken a numeric test to synthesize and inverse the surface displacements for a pop-up structure that is composed of a main thrust and a back thrust. Our result indicates that the pop-up structure, the typical shallow complex rupture that occurred in the northern bending fault zone form Fengyuan to Shuangji, can be modeled better by a thrust fault added negative tensile component than by a simple thrust fault. We interpret the negative tensile distributions, that concentrate on the shallow northern bending fault from Fengyuan to Shuangji, as a the synthetic effect including the complexities of property and geometry of rupture. The earthquake rupture process also reveal the more spatial and temporal complexities form Fenyuan to SHuangji. According to the three-components teleseismic records, the S-wave velocity structure beneath the 59 teleseismic stations of Taiwan obtained by using the transform function method and the SA techniques. The integrated results, the 3D crustal structure of Taiwan reveal that the thickest part of crustal local in the western Central Range. This conclusion is consistent with the result form the Bouguer gravity anomaly. The orogenic evolution of Taiwan is young period, and the developing foot of Central Range dose not in static balancing. The crustal of Taiwan stays in the course of dynamic equilibrium. The rupture process of 2003)2,24,Jiashi, Xinjiang earthquake was estimated by the finite fault model using far field broadband P wave records of CDSN and IRIS. The results indicate that the earthquake focal is north dip trust fault including some left-lateral strike slip. The focal mechanism of this earthquake is different form that of earthquakes occurred in 1997 and 1998, but similar to that of 1996, Artux, Xinjiang earthquake. We interpreted that the earthquake caused trust fault due to the Tarim basin pushing northward and orogeny of Tianshan mountain. In the end, give a brief of future research subject: Building the Real Time Distribute System for rupture process of Large Earthquakes Based on Internet.

用宽频带远震体波波形研究中国及邻近地区地壳构造及地质意义初探

The theory and approach of the broadband teleseismic body waveform inversion are expatiated in this paper, and the defining the crust structure's methods are developed. Based on the teleseismic P-wave data, the theoretic image of the P-wave radical component is calculated via the convolution of the teleseismic P-wave vertical component and the transform function, and thereby a P-wavefrom inversion method is built. The applied results show the approach effective, stable and its resolution high. The exact and reliable teleseismic P waveforms recorded by CDSN and IRIS and its geodynamics are utilized to obtain China and its vicinage lithospheric transfer functions, this region ithospheric structure is inverted through the inversion of reliable transfer functions, the new knowledge about the deep structure of China and its vicinage is obtained, and the reliable seismological evidence is provided to reveal the geodynamic evolution processes and set up the continental collisional theory. The major studies are as follows: Two important methods to study crustal and upper mantle structure -- body wave travel-time inversion and waveform modeling are reviewed systematically. Based on ray theory, travel-time inversion is characterized by simplicity, crustal and upper mantle velocity model can be obtained by using 1-D travel-time inversion preliminary, which introduces the reference model for studying focal location, focal mechanism, and fine structure of crustal and upper mantle. The large-scale lateral inhomogeneity of crustal and upper mantle can be obtained by three-dimensional t ravel-time seismic tomography. Based on elastic dynamics, through the fitting between theoretical seismogram and observed seismogram, waveform modeling can interpret the detail waveform and further uncover one-dimensional fine structure and lateral variation of crustal and upper mantle, especially the media characteristics of singular zones of ray. Whatever travel-time inversion and waveform modeling is supposed under certain approximate conditions, with respective advantages and disadvantages, and provide convincing structure information for elucidating physical and chemical features and geodynamic processes of crustal and upper mantle. Because the direct wave, surface wave, and refraction wave have lower resolution in investigating seismic velocity transitional zone, which is inadequate to study seismic discontinuities. On the contrary, both the converse and reflected wave, which sample the discontinuities directly, must be carefully picked up from seismogram to constrain the velocity transitional zones. Not only can the converse wave and reflected wave study the crustal structure, but also investigate the upper mantle discontinuities. There are a number of global and regional seismic discontinuities in the crustal and upper mantle, which plays a significant role in understanding physical and chemical properties and geodynamic processes of crustal and upper mantle. The broadband teleseismic P waveform inversion is studied particularly. The teleseismic P waveforms contain a lot of information related to source time function, near-source structure, propagation effect through the mantle, receiver structure, and instrument response, receiver function is isolated form teleseismic P waveform through the vector rotation of horizontal components into ray direction and the deconvolution of vertical component from the radial and tangential components of ground motion, the resulting time series is dominated by local receiver structure effect, and is hardly irrelevant to source and deep mantle effects. Receiver function is horizontal response, which eliminate multiple P wave reflection and retain direct wave and P-S converted waves, and is sensitive to the vertical variation of S wave velocity. Velocity structure beneath a seismic station has different response to radial and vertical component of an accident teleseismic P wave. To avoid the limits caused by a simplified assumption on the vertical response, the receiver function method is mended. In the frequency domain, the transfer function is showed by the ratio of radical response and vertical response of the media to P wave. In the time domain, the radial synthetic waveform can be obtained by the convolution of the transfer function with the vertical wave. In order to overcome the numerical instability, generalized reflection and transmission coefficient matrix method is applied to calculate the synthetic waveform so that all multi-reflection and phase conversion response can be included. A new inversion method, VFSA-LM method, is used in this study, which successfully combines very fast simulated annealing method (VFSA) with damped least square inversion method (LM). Synthetic waveform inversion test confirms its effectiveness and efficiency. Broadband teleseismic P waveform inversion is applied in lithospheric velocity study of China and its vicinage. According to the data of high quality CDSN and IRIS, we obtained an outline map showing the distribution of Asian continental crustal thickness. Based on these results gained, the features of distribution of the crustal thickness and outline of crustal structure under the Asian continent have been analyzed and studied. Finally, this paper advances the principal characteristics of the Asian continental crust. There exist four vast areas of relatively minor variations in the crustal thickness, namely, northern, eastern southern and central areas of Asian crust. As a byproduct, the earthquake location is discussed, Which is a basic issue in seismology. Because of the strong trade-off between the assumed initial time and focal depth and the nonlinear of the inversion problems, this issue is not settled at all. Aimed at the problem, a new earthquake location method named SAMS method is presented, In which, the objective function is the absolute value of the remnants of travel times together with the arrival times and use the Fast Simulated Annealing method is used to inverse. Applied in the Chi-Chi event relocation of Taiwan occurred on Sep 21, 2000, the results show that the SAMS method not only can reduce the effects of the trade-off between the initial time and focal depth, but can get better stability and resolving power. At the end of the paper, the inverse Q filtering method for compensating attenuation and frequency dispersion used in the seismic section of depth domain is discussed. According to the forward and inverse results of synthesized seismic records, our Q filtrating operator of the depth domain is consistent with the seismic laws in the absorbing media, which not only considers the effect of the media absorbing of the waves, but also fits the deformation laws, namely the frequency dispersion of the body wave. Two post stacked profiles about 60KM, a neritic area of China processed, the result shows that after the forward Q filtering of the depth domain, the wide of the wavelet of the middle and deep layers is compressed, the resolution and signal noise ratio are enhanced, and the primary sharp and energy distribution of the profile are retained.

库车坳陷-南天山盆山系统第三纪脆性构造研究

Study on the structural coupling relationship between basin and range is not only helpful to recognize the basin formation and evolution systematically, but also to guide petroleum exploration in the basin. As a late Paleozoic Orogen, the South Tianshan Mountains reactivated and uplifted rapidly during the Cenozoic, and led to the Mesozoic-Cenozoic considerable thick deposits in the Kuqa Depression. The researches of the dissertation were carried out in the Kuqa depression-South Tianshan M ountain s ystem, a nd t he b rittle m icrotectonics w. ere c hosen as t he m ost important object. Based on observations and measurements of the field, we made detailed investigations on the geometry and kinematics of this area, and analyzed the abutting and cutting relationships and relative sequence of many brittle structures, such as joint, shear fractures, faults and some small-scale structures related to them closely. According to those brittle fractures' relationships with stress, the nature and variation of regional palaeostress field during the Cenozoic were studied through inversion of fault slip data and inferring stress state from joint sequences. And the deformation time was estimated primarily via ESR dating of faulting. Results show that the stress field varies as well in times as in space. The maximal principal stress direction shifted from the vertical to the horizontal, and stress regime from weak extension to strong compression from the Paleogene to the Neogene regionally. During the late Neogene, the structural deformation of the South Tianshan and the basin-range boundary was dominated by near N-S extension, while near N-S compressive deformation in the interior of the Kuqa Depression. There exits obvious differential stress state from the north to the south. ESR dating of the faulting during the Cenozoic indicates that, the normal faulting in the north edge of the Kuqa Depression have been active all along from the Miocene to the early Pleistocene, but the thrusting and reverse faulting in the interior only been active from the Pliocene to the early Pleistocene. On the base of those geological data and some geophysical information and theoretical calculation results, we infer that, the different stress regime the basin-range system is ascribed to the vertical uplift of the Tianshan Mountain. It was the vertical uplift that lead to the gravity-driven gliding of thick layers lying on the faulted basement from the South Tianshan Mountain to the Kuqa depression, and to folding and thrusting in the interior and frontal of the Kuqa depression. Combining the structural evolution with petroleum geological conditions of the Kuqa Depression, we think that the strong compressive deformation of the Kuqa Depression during rapid uplifting of the Tianshan Mountains from the Pliocene to the early Pleistocene play crucial role in the structural trap formation and proliferous gas accumulation.

黄骅坳陷高尘头地区储层非均质性及成藏研究

Gaochentou region is located in the southwest direction of Gaochentou village in Huanghua city of Hebei province. In regionally structural position, It lies in Qikou sag In the middle part of Huanghua depression, which belongs to the east part of the south Dagang structure zone in the middle part of Huanghua depression. Its' very beneficial at regional structure in Gaochentou , and It becomes the advantage area for oil and gas gathered and preserved, Sandstone reservoir of Dongying Formation is main bearing bed .Dongying Formation in Gaochentou region of Huanghua depression is consisted of set of mudstone and sandstone interbeds by deposited delta fades . Dongying Formation can be divided into 3 members from above to below: the first member of Dongying Formation (FMDF), the second member of Dongying Formation (SMDF), and third member of Dongying Formation (TMDF). The lithology of the upper part of FMDF was consisted of mostly middle-grained and fine-grained sandstone, and it is small for the oil-bearing area of the sand bodies .The lithology of the lower part is coarse-grained sandstone bodies which are well connected between sandstone bodies of wells, and the lower part was main bed of oil production in Dongying Formation; SMDF and TMDF are consisted of larger scale set of mudstone, in which the sandbodies are lenticular and pinch out quickly, and the lithology was mostly fine sandstone and silt stone, in which there are little oil and gas .Because the reservoirs in this area are largely influenced by the factors such as lithology, fault and others, and the reservoirs have the strong,heterogeneity , there exists the problem of oil-down and water-up for vertical distribution of oil and gas bearing. It is not very clearly for the three dimension distribution of sandstone , and the geology researchs is not enough. So, it can't satisfy the need of further development and production for Gaochentou oilfield.Having the key problem of oil-down and water-up and the mechanism of the reservoir for Gaochentou area, There are as follow study works, the first, is study of the high-resolution correlation of sequence stratigraphy and sedimentary microfacies. Dongying Formation was divided into three parasequence sets and each parasequence set was divided into different amount of parasequences. FMDF, as the main oil and gas producing bed, can be divided into seven parasequences. Oil and gas are discovered in six parasequences except the seventh. On the basis of study of sedimentary microfacies, the sediments of Dongying Formation are considered deposited mainly in delta front subfacies. The microfacies types of Dongying Formation are sub-water distirbutary channel, sub-water natural bank, inter distributary channel bay, distributary channel mouth dam, and delta front mat sand.Seismic facies analysis and logging-constrained inversion technique were applied by Author for transverse prediction of sandstone reservoir. Having 4 modes of interwell single sandbodies correlation technique, Author have described distribution characteristics of sandbodies, and established geological reservoir model of Gaochentou reservoir.Author presented that the reservoirs characteristic have very strong heterogeneity ,and In the section of sandstone interlayed with mudstone,the folium sandstone interlayed with each other, and the wedge shaped sandbodies pinched out in the mudstone. So the pinch-out up sandstone trap and lenticular sandstone trap are easily formed. They are most small scale overlying pinches out in the place of slope. This article applies the concept of deep basin oil to resolve reasonably the problem of which the oil is below the water in Gaochentou area. Combined with the study of sedimentary facies, reservoir and other aspects, the mechanism and patterns of deep basin oil are studied on the basis of characteristics in Gaochentou area.On the basis of the above study, the mechanism of the oil and gas' migration and accumulation in isotropic sandstone and heterogeneous sandstone are thoroughly analyzed through experiments on physical modeling. Experiments on physical modeling show that the discrepancy between sand layers with different permeability and thickness has important influence on the direction, path, and injection layer of oil's migration. At the beginning of the injection of oil and gas in high permeability sand layer, the pressure is low, the migration resistance is small, and the oil and gas are more easily displacing the water in sand. So it can act as good transformation layer or reservoir. But at the beginning of the injection of oil and gas in sand layer with low permeability, the pressure is high, the migration resistance is big, and the oil and gas are more difficultly displacing the water in sand. So it can only act as bad or worse transformation layer or reservoir. Even if it cannot act as transformation layer or reservoir, it can act as water layer or dry layer. The discrepancy between sand layers on permeability and thickness can make discrepancy in injection of oil and gas between different layers. Consequently it leads to small amount of oil and gas injection in sand layers with low permeability. Ultimately it affects the oil's accumulation and distribution in different sand layers.At Last, combining analysis of the structure and pool forming condition, The thesis has established models of reservoir formation to predict the advantage distribution of oil and gas bearing , and put forward the prospective target It is not only of theoretical signification for explosion and importance, but also has realistic value in guiding the progressive petroleum exploration and exploitation.

地震反射界面形态与介质各向异性属性联立成像：地震反射波旅行时与偏振信息综合反演

It has been a difficult problem faced by seismologists for long time that how exactly to reconstruct the earth's geometric structure and distribution of physical attributes according to seismic wave's kinematical and dynamic characteristics, obtained in seismological observation. The jointing imaging of seismic reflector and anisotropy attributes in the earth interior is becoming the research hot spot. The limitation of shoot and observation system makes that the obtained seismic data are too scarce to exactly reconstruct the geological objects. It is popular that utilizing only seismic reflection traveltimes or polarizations information make inversion of the earth's velocity distribution by fixing seismic reflector configuration (vice versa), these will lead to the serious non-uniqueness reconstruction due to short of effective data, the non-uniqueness problem of reconstructing anisotropy attributes will be more serious than in isotropy media. Obviously it is not enough to restrict the media structure only by information of seismic reflection traveltimes or polarizations, which even sometimes will lead to distorted images and misinterpretation of subsurface structure. So we try to rebuild seismic reflection structure (geometry) and media anisotropic structure (physics) in the earth interior by jointing data of seismic wave kinematics and dynamics characteristics, we carry out the new experiment step by step, and the research mainly comprises of two parts: one is the reconstruction of P-wave vertical velocity and anisotropic structure(Thomsen parameter s and 8) in the transversely isotropic media with vertical symmetrical axis(VTI) by fixing geometrical structure, and the other is the simultaneous inversion of the reflector surface conformation and seismic anisotropic structure by jointing seismic reflection traveltimes and polarizations data. Simulated annealing method is used to the first research part, linear inversion based on BG theory and Simulated annealing are applied to the second one. All the research methods are checked by model experiments, then applied to the real data of the wide-angle seismic profile from Tunxi, Anhui Province, to Wenzhou, Zhejiang Province. The results are as following The inversion results based on jointing seismic PP-wave or PSV-wavereflection traveltimes and polarizations data are more close to real model than themodels based simply on one of the two data respectively. It is shown that the methodwe present here can effectively reconstruct the anisotropy attributes in the earth'sinterior when seismic reflector structure is fixed.The layer thickness, P-wave vertical velocity and Thomsen anisotropicparameters {s and 8) could be resolved simultaneously by jointing inversion ofseismic reflection traveltimes and polarizations with the linear inversion methodbased on BG theory.The image of the reflector structure, P-wave vertical velocity and theanisotropy parameters in the crust could be obtained from the wide-angle seismicprofile from Tunxi (in Anhui Province), to Wenzhou (in Zhejiang Province). Theresults reveal the difference of the reflector geometrical structure and physicalattributes in the crust between Yangtze block and Cathaysia block, and attempt tounderstand the characteristics of the crustal stress field in the areas.