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3-D multi-parameter type traveltime tomography in a spherical coordinate frame: comparison of double and triple class simultaneous inversions 
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下载免费PDF全文 It is now common practice to perform simultaneous traveltime inversion for the velocity field and the reflector geometry in reflection/refraction tomography, or the velocity field and the hypocenter locations in regional earthquake tomography, but seldom are all three classes of model parameters updated simultaneously. This is mainly due to the trade-off between the different types of model parameters and the lack of different seismic phases to constrain the model parameters. Using a spherical-coordinate ray tracing algorithm for first and later(primary reflected) arrival tracing algorithm in combination with a popular linearized inversion solver, it is possible to simultaneously recover the three classes of model parameters in regional or global tomographic studies. In this paper we incorporate the multistage irregular shortest-path ray tracing algorithm(in a spherical coordinate system) with a subspace inversion solver to formulate a simultaneous inversion algorithm for triple model parameters updating using direct and later arrival time information.Comparison tests for two sets of data(noise free and added noise) indicate that the new triple-class parameter inversion algorithm is capable of obtaining nearly the same results as the double-class parameter inversion scheme. Furthermore,the proposed multi-parameter type inversion method is not sensitive to a modest level of picking error in the traveltime data, and also performs well with a relatively large uncertainty in earthquake hypocentral locations. This shows it to be a feasible and promising approach in regional or global tomographic applications. 相似文献
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本文首先对Envisat/ASAR数据进行干涉处理, 获取2011年日本东北MW9.0地震的地表InSAR同震形变场; 然后通过对InSAR同震形变数据重采样方法的深入分析, 选择条纹率法结合干涉图的空间相干性对InSAR同震形变数据进行重采样; 最后基于弹性半空间位错模型, 联合InSAR与GPS形变数据, 采用最小二乘法反演发震断层的滑动分布. 研究结果表明: 考虑相干性的条纹率重采样方法, 更适用于形变场中存在除断层外的有限边界、 且形变场范围较大的InSAR数据重采样处理; 断层滑动主要发生在地表以下50 km范围内, 最大滑动量为49.9 m, 矩张量为4.89×1022 N·m, 所对应的矩震级为MW9.1, 与地震学反演的结果比较吻合. 相似文献
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GPS AND LEVELING CONSTRAINED CO-SEISMIC SOURCE AND SLIP DISTRIBUTION OF THE LUSHAN MS7.0 EARTHQUAKE ON 20 APRIL 2013 下载免费PDF全文
下载免费PDF全文 Co-seismic deformation results calculated by the observations of GPS continuous sites and precise leveling are used as three-dimensional constraints for the deformation field of Lushan MS7.0 earthquake on 20 April 2013.The inversion of seismic source parameters are calculated based on the consideration of different value-taking schemes and fault models. Seven data type selection schemes, three fault models and two data coverage selection schemes are designed in order to discuss the effect of data selection and fault model selection on the inversion results.
The results show that the fault model using blind reverse fault for the inversion is superior to the model using the fault that ruptures from its upper boundary to the earth'surface, which may indicate that the Lushan earthquake fault is most likely a blind reverse fault; there are no obvious differences in the inversion results between the blind listric reverse fault models and the rectangle blind reverse fault models.
The best inversion result of Lushan earthquake seismic moment is MW6.7.And it also shows that the distribution of dislocations on the fault plane is concentrated in the range of 30km×30km, the northern flank of the seismogenic fault of Lushun earthquake is of dextral faulting and the southern flank of the fault is of sinistral faulting, the sinistral component is larger that dextral component, showing a wedge deformation mode. 相似文献
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Weiwen Chen Sidao Ni Shengji Wei Zhenjie Wang Jun Xie Mengcheng National Geophysical Observatory University of Science Technology of China Hefei China CAS Key Laboratory of Geodynamical Geodesy 《地震学报(英文版)》2011,(2):221-227
Ground deformation as observed with GPS or InSAR has been broadly inverted in constraining source parameter of earthquakes. However, for earthquakes occurring beneath sedimentary basins, the very slow sub-surface shear velocity (v S , down to 200 m/s) may cause substantial bias to earthquake source inversion if simple crustal models are used. For Bohai basin, Sichuan basin and rock-sites, we test effects of sub-surface shear velocity structure on ground deformation, and find that up to a factor of 2 overest... 相似文献
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利用天然地震记录直达P波后续20s内的波形信息,研究了地壳、土地慢速度结构反演的方法、唯一性、精度及应注意的问题,并将求解有条件极值的惩罚数法和求解无条件极值的单纯形法引入到波形反演.数值计算证明,波形反演方法对记录的误差有压制作用,在深源、远震、各向同性水平层状近似合理的前提下,可用一个地震事件在射线平面内的二分量记录反演台站区地壳、上地幔P、S波速度结构.在新疆天山地区转换波流动台站观测中,选择出较好的记录进行波形反演,给出了该转换被测深剖面上6个台站下方的地壳、上地慢P、S波速度结构.通过塔里木盆地内一测点上波形反演和地震勘探结果的对比证明,波形反演方法具有满意的精度. 相似文献
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2015年4月25日尼泊尔MW7.8地震发生在喜马拉雅造山带上,人们普遍认为该地震不足以释放该造山带上累积的能量,但对该地区后续地震危险性评价多基于二维或是假三维的形变反演计算结果.本研究从2015年尼泊尔地震主震与其最大余震MW7.3地震之间的关系出发,着重分析讨论了尼泊尔地震的时间和空间的非均匀性,结合震源机制解、地壳速度结构、精定位后的余震分布及InSAR反演结果,建立了三维发震构造模型,利用非线性摩擦有限元方法,对一个地震周期内断层摩擦行为和块体变形进行了模拟,将计算结果和地表同震形变、形变反演的同震破裂、历史地震时空演化进行对比,在确认该三维模型可靠性的基础上,讨论了该地区后续地震的可能位置,认为在1934年比哈—尼泊尔MW~8.1地震以东区域,还存在发生大地震的可能,在最大余震MW7.3地震东南部位,还存在发生中大地震的可能. 相似文献
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2017年11月13日伊拉克北部地区苏莱曼尼亚省发生了MW7.3地震, 造成了重大的人员和经济损失。 本文利用升降轨的Sentinel-1和降轨的ALOS-2卫星的SAR数据, 通过差分干涉测量技术获取了该地震的同震形变场, 联合DInSAR和MAI技术, 采用抗差最小二乘法求解该地震的同震三维形变场。 基于改进的考虑地形起伏的均匀位错模型反演确定了发震断层的断层参数, 最后基于非均匀位错模型得到了发震断层的分布式滑动分布模型。 结果显示: ALOS-2卫星降轨轨道观测到的伊拉克地震引起的LOS向地表形变最大为55.8 cm抬升和47.9 cm下沉; Sentinel-1卫星观测到的伊拉克地震引起的LOS向地表形变为: 升轨轨道最大为87.9 cm抬升和17.1 cm下沉; 降轨轨道最大为55.6 cm抬升和38 cm下沉; 相对于前人的研究成果, 本文利用改进的考虑地形起伏的反演方法得到的发震断层几何参数表明发震断层为NNW走向, 倾向角为352°, 同震破裂以逆冲为主, 同时兼有一定的左旋走滑分量。 基于均匀位错模型反演得到的断层滑动分布结果表明, 同震破裂未延伸至地表, 主要滑动量集中在12~18 km, 最大滑动量位于15 km深度, 达到4.3m, 反演得到的矩震级为MW7.35, 与UGSG、 GCMT等机构给出的结果一致。 相似文献
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The conductivity anisotropy behaviour is described for certain environment in the Earth’s crust and the MT inversion method
for a layered symmetrically anisotropic model is presented. The inversion interpretations of the anisotropic model from the
observational data are helpful to identify the earthquake precusors as indicated by the deep conductivity anisotropic variations,
and also provide some useful information to investigate the stress states and deformation bands in the deep crust of the Earth.
This project is sponsored by the Chinese Joint Seismological Science Foundation. 相似文献
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利用现代空间大地测量技术,尤其是卫星合成孔径雷达干涉测量,能够获取高精度、高空间分辨率的同震和孕震形变,为地震断层形变和破裂机制研究提供了前所未有的机遇。本文介绍了利用大地测量观测数据反演地震断层位错模型参数的贝叶斯反演方法。联合运用2008汶川大地震前后GNSS和InSAR技术观测获得的同震位移,反演了地震断层的几何参数和滑动位错分布。研究结果表明,汶川地震的断层滑动主要集中在倾角较陡的浅部,同时包含逆冲和右旋走滑,其中最大逆冲6.1m,最大右旋6.5m。根据断层滑动分布正演计算得到的上盘同震位移明显小于下盘,预示该断层两侧孕震形变可能存在较大的不对称性。 相似文献
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王健 《地震学报(英文版)》2001,14(3):274-279
IntroductionIt is an important approach to research on earthquake phenomena, an elemental portion of seismology, for understanding seismic activities. Aim of seismic pattern procession is to research spatial-temporal distribution of epicenters and generalize saliently seismic characteristics, to explore the regularities of seismicity and earthquake mechanism. People acquaint earthquake phenomena gradually with development of observation technique. Initially we could only feel and record destru… 相似文献
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为了精确得到大陆地震震源位置,利用模拟退火法对大陆地震参数进行反演,并对改变算法中相关参数后的反演结果进行分析,表明反演精度受降温速度和收敛阈值的影响较大,初始温度只影响迭代次数,模拟退火法在对模型参数进行全局搜索情况下能获得质量较好的最优解。 相似文献
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2017年8月8日我国四川九寨沟发生里氏7.0级地震.本研究利用基线校正方法获得距震中100km范围内9个强震台站同震位移,基于Sentinel-1卫星干涉SAR影像对获取了InSAR同震形变场.结合GPS形变数据,本研究进行了震源滑动模型联合反演,结果显示此次地震整体以走滑运动为主,释放地震矩约为7.60×1018 N·m(～MW6.52).通过对比模拟形变场和观测值显示,联合反演结果优于单独基于InSAR形变场的反演结果.静态应力变化计算结果显示断层平均静态应力降为1.07MPa.反演滑动模型沿走向和倾角方向拐角波数值分别为0.99×10-4和1.10×10-4.同震静态库仑应力变化计算结果显示共有83.6%的余震位于库仑应力增加的区域,被主震所触发的余震占总数的77.9%,主震对后续余震具有显著触发作用.强地面运动模拟结果显示模拟结果在烈度分布范围和等级方面与调查烈度符合度很高,模拟结果能够很好地反映断层破裂的方向性效应等特征.本研究计算结果显示九寨沟地震无论是平均静态应力降还是拐角波数均低于同类型地震的平均水平,这可能是造成本次地震强地震动水平相对不高的原因. 相似文献
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The Akto M_S6. 7 earthquake occurred near the western end of the Muji fault basin in the top of the Pamir syntaxis. The main shock of this earthquake is complicated and the focal mechanism solutions based on the seismic wave inversions are different. Based on the Sentinel-1 SAR data,the coseismal deformation field of the earthquake is obtained by In SAR technique. Based on the elastic half-space dislocation model,the geometrical parameters and the slip distribution model are determined by nonlinear and linear inversion algorithms. The results show that the distributed slip model can well explain the coseismic deformation field. The earthquake includes at least two rupture events,which are located at 7 km(74. 11°E,39. 25°N)and 33 km(74. 49°E,39. 16°N)east from the epicenter according to the CENC. The deformation field caused by the earthquake shows a symmetry distribution,with the maximum LOS deformation of 20 cm. The main seismic slip is concentrated in the 0-20 km depth,and the maximum slip is 0. 84 m. The seismic fault is the Muji fault,and this earthquake indicates that the northeastward push of the Indian plate is enhanced. 相似文献
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Surface wave methods are becoming increasingly popular in many geotechnical applications and in earthquake seismology due to their noninvasive characteristics.Inverse surface wave dispersion curves are a crucial step in most surface wave methods.Many inversion methods have been applied to surface wave dispersion curve inversion,including linearized inversion and nonlinearized inversion methods.In this study,a hybrid inversion method of Damped Least Squares(DLS) with Very Fast Simulated Annealing(VFSA) is developed for multi-mode Rayleigh wave dispersion curve inversion.Both synthetic and in situ fi eld data were used to verify the validity of the proposed method.The results show that the proposed method is superior to the conventional VFSA method in aiming at global minimum,especially when parameter searching space is adjacent to real values of the parameters.The advantage of the new method is that it retains both the merits of VFSA for global search and DLS for local search.At high temperatures,the global search dominates the runs,while at a low temperatures,the local search dominates the runs.Thus,at low temperatures,the proposed method can almost directly approach the actual model. 相似文献
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通过对我国地震台网观测资料以及地震活动特征的分析，给出了处理中小地震活动性图象的网格点密集值计算方法．该方法综合考虑一定时空及震级范围内地震的数量和震中分布这两方面因素，并特别强调了计算参量的选取应充分考虑资料精度的影响．应用该方法得到的地震活动性图象能够准确、合理地反映地震活动特征并具有较好的稳定性．经该方法处理的图象是对地震活动性进行定量分析的基础，在地震趋势分析、中长期地震预测以及防震减灾等方面有很好的应用前景． 相似文献
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ＲｅｓｅａｒｃｈｏｆｐａｔｔｅｒｎｄｙｎａｍｉｃｓｐａｒａｍｅｔｅｒｓｏｆｃｒｕｓｔａｌｄｅｆｏｒｍａｔｉｏｎｆｉｅｌｄｉｎｓｅｉｓｍｏｇｅｎｉｃｐｒｏｃｅｓｓＳｈｕｏ－ＹｕＺＨＯＵ（周硕愚），ＹｕｎＷＵ（吴云），Ｒｕｏ－ＢｏＷＡＮＧ（王若柏）ａｎｄ... 相似文献
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Chengli Liu Bin Shan Yong Zheng Ying Jiang Xiong Xiong Key Laboratory of Dynamic Geodesy 《地震学报(英文版)》2011,(2):177-183
Based on the elastic dislocation theory, multilayered crustal model, and rupture model obtained by seismic waveform inversion, we calculated the coand post-seismic surface deformation and gravity changes caused by the Yushu M W 6.9 earthquake occurred on April 14, 2010. The observed GPS velocity field and gravity field in Yushu areas are disturbed by the coand post-seismic effects induced by Yushu earthquake, thus the theoretical coand post-seismic deformation and gravity changes will provide important modi... 相似文献