基于向-位错模型的同震断层运动反演——以龙门山断层为例     

张永志  张本平  王卫东  王帅 《地球学报》2016,37(3):294-300

针对2008年发生汶川8.0级地震的龙门山断裂铲状分布和断层倾滑面倾角随深度变化特点,本文提出了描述龙门山断层同震运动(滑动和转动)的向-位错组合模型。结合地质数据采用回归分析法模拟了断层在倾滑过程中断层面倾滑方向随断层深度的分布特征;利用四川地区实测的三维同震GPS数据结合粒子群算法,采用向-位错模型对汶川地震断层面的同震滑动和随深度的方向转动(向错)进行了反演计算,并将反演的同震滑动区域和大小分布与USGS断层滑动结果进行了对比分析。理论分析和模型计算表明:(1)在汶川8.0级地震发生过程中,由于断层的倾滑面为倾角由上向下逐渐变小的曲面,断层面上的倾滑方向也随断层面法线的改变而变化,即断层面在破裂过程中存在明显的向错现象;(2)龙门山发震断层的倾滑面转动方向随深度变化为一开口向上的抛物线,震中位于转动角变化的极值点附近;(3)在断层几何参数相同的情况下,采用向-位错组合模型反演的同震滑动区域和USGS的滑动区域具有较好的一致性,滑动大小的差异主要由断层模型之间的差异、测量误差等多种因素引起。  相似文献   

On the interpretation of slow ground deformation precursory to the 1976 Friuli earthquake     

Michele Dragoni  Maurizio Bonafede  Enzo Boschi 《Pure and Applied Geophysics》1984,122(6):781-792

During three years preceding the 1976 Friuli earthquake, a continuous southward ground tilt was recorded by a tiltmeter placed near Tolmezzo, 15 km north-west of the epicentre of the impending earthquake. The cumulative ground tilt amounted to as much as 3 minutes of arc. Since the tiltmeter was placed in the proximity of an active fault, such a tilt can be explained if the fault slipped aseismically on its shallower section during the same three year period. Aseismic slip on the fault might have been caused by the same mechanism which concentrated stress in the region and eventually produced the 1976 earthquake.  相似文献   

Rotated staurolite porphyroblasts in the Littleton Schist at Bolton, Connecticut, USA   总被引：2，自引：0，他引：2  

M. D. BUSA  N. H. GRAY 《Journal of Metamorphic Geology》1992,10(5):627-636

Staurolite porphyroblasts, 1.5–8cm in length and 0.3–2cm in width, in the Littleton Schist at Bolton, Connecticut, contain curved quartz inclusion trails which document synkinematic rotations of at least 135°. The orientations of long axes of these staurolite crystals define a weak preferred orientation in a plane approximately parallel to the external foliation. Serial sections of four differently orientated crystals and U-stage measurements of the orientations of their inclusion trails demonstrate that the inflection hinge line and the statistical 'symmetry axis' characterizing the foliation within a porphyroblast are unrelated to the orientations of external crenulations and are, in all cases, parallel to the long axis of the porphyroblast. The cumulative rotation reflected in the curvature of the inclusion trails is a maximum in a c -axis section through the initial core of a crystal. The amount of rotation about the c -axis decreases linearly along the length of the crystal away from the nucleation site.
The sense and amount of rotation recorded by a porphyroblast is related to its orientation. A tightly constrained transition from clockwise to anticlockwise rotation defines a slip direction that coincides with the preferred orientation of the staurolite c -axes. The total rotation reflected by the inclusion trails increases as a function of the angle between the c -axes of the staurolite crystals and the slip direction.
Initially random staurolite porphyroblasts rotated during growth, as a consequence of laminar shear in the surrounding viscous matrix. This interpretation is quantitatively consistent with: the staurolite preferred orientation; its coincidence with the apparent slip direction; the correlation between both the sense and the amount of rotation and the orientation of the long axis of the porphyroblast; and the twisted conical shape of the family of surfaces defined by the inclusion trails.  相似文献   

Geodetic data inversion using a Bayesian information criterion for spatial distribution of fault slip   总被引：7，自引：0，他引：7  

T. Yabuki  M. Matsu'ura 《Geophysical Journal International》1992,109(2):363-375

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基于模糊小波神经网络算法的汽车滑移率控制研究     

薛艳梅  杨青青  邵珂 《南京气象学院学报》2016,8(5):415-420

防抱死系统是汽车制动过程非常重要的基本安全措施,滑移率控制是汽车防抱死控制的重要组成部分.汽车的制动过程是一个与实时路况相关的时变、非线性、不确定系统.针对该问题开展基于模糊小波神经网络算法的滑移率控制研究.通过采用模糊小波神经网络估计系统模型的非线性、时变不易获知的部分,结合等效控制思想来构造滑模控制法则,从而实现期望的滑移率控制.Matlab-simulink仿真结果表明,所设计的算法具有良好的鲁棒性能,能有效、快速地到达期望的滑移率.  相似文献   

华北克拉通东南部蚌埠隆起晚中生代花岗岩类岩体内变形记录与构造意义   总被引：5，自引：0，他引：5  

宋利宏  朱光  赵田  林少泽 《地质论评》2016,62(2):400-418

华北克拉通东南部蚌埠隆起上出露了一系列晚中生代花岗岩类岩体,记录了丰富的变形过程。本次与前人锆石定年结果表明,该区经历过两期岩浆活动,分别是中—晚侏罗世(167～148 Ma)和早白垩世(130～112Ma)。区内晚侏罗世蚂蚁山岩体记录了切过该岩体的一条北北东向左行韧性变形带,是北北西—南南东向挤压的产物。该走滑变形带在走滑隆升中又被脆性平移断层所叠加。走滑活动时间可以限定在148～130 Ma之间。研究区在130～112 Ma期间转变为强烈的伸展活动,区域拉张方向为北西西—南东东向,并伴随着岩浆活动与区域隆升。在此伸展过程中,中—晚侏罗世荆山—涂山岩体与早白垩世淮光岩体记录了深部韧性伸展拆离变形带抬升至浅部被脆性正断层所叠加的变形过程,而其它岩体内均记录了地壳浅部的脆性正断层活动。这些岩体的变形记录,指示华北克拉通东部晚中生代由挤压向伸展构造体制转变发生在148～130 Ma期间,提供了在早白垩世克拉通峰期破坏中目前非盆地区构造过程的实例。  相似文献   

瞬态面波法在滑坡体勘探中的应用     

林锦霞  林厚龙  林明海 《福建地质》2007,26(4):266-269

多道瞬态瑞雷波勘探技术是近几年来快速发展起来的高新技术,在滑坡体工程勘察中具有广泛的应用前景.介绍多道瞬态瑞雷波勘探原理及技术方法,并通过工程勘察实例,说明多道瞬态瑞雷波法应用于滑坡体勘察的可行性与有效性.  相似文献   

A grid-search inversion method looking for the best classification of polyphase fault/slip data     

Yehua Shan  Faxiong Gong  Zian Li  Ge Lin 《Tectonophysics》2007,433(1-4):53-64

A novel, grid search-based stress inversion method is developed in this paper to find the global minima in the solution region for the classification of fault/slip data into many single-phase subsets. Exhaustively repetitious grid searches are taken to deal with possible local minima, in a departure from existing grid search-based inversion methods. Two stopping rules, to stop at the abrupt change of the objective function or at the least change of the classification, are adopted in the method to look for the best classification. Much calculation time is saved by using a modified version of conventional grid search. The feasibility of this proposed method is demonstrated by applying it to two artificial examples and two real examples. However, enormous time in calculation is still needed in the case of a data set either with a large number of data or for a large number of assigned subsets.  相似文献   

Experimental analysis and modelling of shallow landslides   总被引：1，自引：1，他引：1  

Lorella Montrasio  Roberto Valentino 《Landslides》2007,4(3):291-296

The paper presents the results of some experimental tests reproducing the triggering mechanism of a special kind of shallow landslides induced by rainfalls (soil slip) in a physical 1-g model. The experimental data have been employed to verify the capability of a simplified stability model to describe the phenomenon and to back-analyse its occurrence in a case history (Pizzo d’Alvano, Campania Region 1998). The method enables a direct correlation between the safety factor of a slope and rainfall intensity, as well as antecedent rainfalls.  相似文献   

准噶尔南缘新生代断裂的形成机制   总被引：3，自引：0，他引：3  

卢华复  王胜利  贾承造 《地学前缘》2007,14(4):168-174

准南有三条走向东西右列的新生代冲断褶皱带,是天山北麓右行走滑兼走逆冲断层的尾端冲断扇构造。各冲断褶皱带的西端与天山北麓断层相接触处形成最早,在中新世中期开始形成,主体在中新世晚期约10Ma开始形成,其末端在第四纪才开始形成,表现出挤压的构造动力和变形自南向北扩展。准南逆冲构造带的初始时间比天山南麓的库车逆冲构造带晚约8Ma,说明天山造山带因为塑性较高,构造动力传播是耗时的,这与塔里木盆地刚性高、瞬时传递的特征形成对照。瞬时传递构造应力和耗时传递构造动力在空间上的交替出现是印藏陆陆碰撞导致陆内变形传播形式的基本原因。  相似文献