Lithology-derived structure classification from the joint interpretation of magnetotelluric and seismic models     

P. A. Bedrosian  N. Maercklin  U. Weckmann  Y. Bartov  T. Ryberg  O. Ritter 《Geophysical Journal International》2007,170(2):737-748

Magnetotelluric and seismic methods provide complementary information about the resistivity and velocity structure of the subsurface on similar scales and resolutions. No global relation, however, exists between these parameters, and correlations are often valid for only a limited target area. Independently derived inverse models from these methods can be combined using a classification approach to map geologic structure. The method employed is based solely on the statistical correlation of physical properties in a joint parameter space and is independent of theoretical or empirical relations linking electrical and seismic parameters. Regions of high correlation (classes) between resistivity and velocity can in turn be mapped back and re-examined in depth section. The spatial distribution of these classes, and the boundaries between them, provide structural information not evident in the individual models. This method is applied to a 10 km long profile crossing the Dead Sea Transform in Jordan. Several prominent classes are identified with specific lithologies in accordance with local geology. An abrupt change in lithology across the fault, together with vertical uplift of the basement suggest the fault is sub-vertical within the upper crust.  相似文献   

Modelling and inversion of single-ended refraction data from the shot gathers of multifold deep seismic reflection profiling—an approach for deriving the shallow velocity structure     

V. Vijaya Rao  Kalachand Sain  V. G. Krishna 《Geophysical Journal International》2007,169(2):507-514

A multifold crustal-scale deep seismic near-vertical reflection profile generates a large number of single-ended shot gathers, which provide redundant data sets because of overlapping coverage of the shallow refractors. We present an approach for deriving the shallow velocity structure by modelling and inversion of single-ended seismic refraction first arrival traveltime data. We apply this method to a data set acquired with a 12-km long spread with 100 m spacing of shots and receivers, of the Neoproterozoic Marwar basin in the NW Indian shield. The approach is shown to be quite successful for delineating the shallow refractor depths, steep dips and velocities, even in the absence of regular reverse refraction profiles. The study reveals two-layered sedimentary formations, Malani volcanics and a complicated basement configuration of the Marwar basin, and provides a measure of resolution and uncertainty of the estimated model parameters. A seismic section of the near-trace gather is found to be qualitatively consistent with the derived structural features of the basin. The relative highs and lows, observed in the Bouguer gravity profile, further corroborate the derived velocity model. The present approach can be especially useful in offshore areas and elsewhere, where the single-ended multifold seismic profiles are the only available data sets.  相似文献   

Statistical properties of seismicity of fault zones at different evolutionary stages     

G. Hillers  P. M. Mai  Y. Ben-Zion  J.-P. Ampuero 《Geophysical Journal International》2007,169(2):515-533

We perform a systematic parameter space study of the seismic response of a large fault with different levels of heterogeneity, using a 3-D elastic framework within the continuum limit. The fault is governed by rate-and-state friction and simulations are performed for model realizations with frictional and large scale properties characterized by different ranges of size scales. We use a number of seismicity and stress functions to characterize different types of seismic responses and test the correlation between hypocenter locations and the employed distributions of model parameters. The simulated hypocenters are found to correlate significantly with small L values of the rate-and-state friction. The final sizes of earthquakes are correlated with physical properties at their nucleation sites. The obtained stacked scaling relations are overall self-similar and have good correspondence with properties of natural earthquakes.  相似文献   

Post-seismic motion following the 1997 Manyi (Tibet) earthquake: InSAR observations and modelling   总被引：2，自引：0，他引：2  

Isabelle Ryder  Barry Parsons  Tim J. Wright  Gareth J. Funning 《Geophysical Journal International》2007,169(3):1009-1027

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基于GPS的青藏块体东北缘近期地壳水平运动与变形研究     

李天文  梁伟锋  冯丽丽  刘军华  王庆良  崔笃信 《干旱区地理》2007,30(5):637-645

以"中国地壳运动观测网络"工程1999-2001年GPS观测数据以及"大陆强震机理与预测"国家基础研究项目青藏块体东北缘GPS网1999,2001,2003年的观测资料为基础,应用GAM IT/GLOBK软件对数据进行精密解算,获得了青藏块体东北缘1999-2001年相对于鼎新基准站以及欧亚板块的水平运动速度场。结合板块构造以及大地动力学理论,对青藏块体进行了块体的划分,分析了块体间的相互作用,并进一步分析了该地区的地壳水平运动特征,得出了以下结论:(1)GPS技术用于地壳运动的监测是可行的;(2)1999-2001年期间,祁连-海原断裂带GPS运动位移与地质结果十分吻合;(3)印度板块与欧亚板块的碰撞以碰撞后印度大陆继续以50 mm/a的速度向北推进是青藏块体东北缘的运动动力;(4)甘青块体西部子块体以北东向挤压运动为主;东部子块体主要表现为以海原断裂带为北边界的顺时针旋转为主;(5)鄂尔多斯块体存在逆时针旋转运动,其旋转速度在块体西南侧的六盘山断裂带一带最大,向北至块体西北部明显减小。  相似文献   

Crustal Stress Measurement for Significant Project Construction and Its Application in Design     

Guo Qiliang 《中国地震研究》2007,21(3):345-354

The hydrofracturing technique has developed into a reliable and practical method for determining the original three-dimensional crustal stress state of underground caverns,the load-bearing capacity of a high pressure cavern itself,and the high pressure hydraulic permeability of rock masses,and has also been extensively used in disposal of nuclear waste,long and deeply-buried traffic channels and high-pressure cavern engineering for hydraulic power plants.The practice shows that the comprehensive measurement of the physical parameters of the rock mass and taking full use of the wall rock load-bearing capacity to optimize the engineering design hold are very useful in ensuring the engineering safety and improving the design level.  相似文献   

Crustal structure using receiver function in the east part of A＇nyemaqen suture belt     

段永红张先康  刘志徐朝繁  王夫运潘纪顺 梁国经 《地震学报(英文版)》2007,20(5):513-522

Twenty broadband seismographs were deployed along Hongyuan, Sichuan to Wuwei, Gansu. 81 teleseismic events were recorded in one year. We computed receiver functions from teleseismic waveform data and obtained S wave velocity structure beneath each station along the profile by using receiver function inversion method. The results revealed that the crustal structure is very complex and crustal average S wave velocity is to be on the low side. Low velocity structure generally exists in the depth range of 10～40 km in the crust between Aba arc fault and northern edge fault of Qinling earth＇s axis and it is a tectonic feature of complex geological process such as ancient A＇nyemaqen Tethys ocean from closing and side colliding to subducted plate exhumed or thrust rock slice lifted. The Moho is about 50 km depth along the profile and is slightly deeper in the south than in the north.  相似文献   

使用纵波和横波走时层析成像研究菲律宾海板块西边缘带和南海地区的深部结构   总被引：5，自引：7，他引：5       下载免费PDF全文

瞿辰  周蕙兰  赵大鹏 《地球物理学报》2007,50(6):1757-1768

使用纵波震相及同台同源纵波和横波震相的走时资料及层析成像反演方法，分别给出了菲律宾海板块(PHP)和南海地区的纵波速度V_pf及同台同源的纵波和横波速度V_p和V_s结构. 结果表明，（1） PHP与欧亚板块(EUAP)的俯冲接触关系随地段而异，在琉球海沟，PHP向EUAP之下俯冲深达400 km；在台湾岛，EUAP先近陡直地俯冲到深度400 km，然后折向PHP之下达到660 km左右；在马尼拉海沟北段，俯冲板片几乎垂直达到660 km附近；在菲律宾海沟，PHP向EUAP之下的俯冲深度超过660 km．（2）南海地区之下是一个深达300～400 km的宽阔低速区，并且大致在莺琼海盆与700 km深处另一低速区曲折相通；在该宽阔低速区内部，有两个小而明显的低速区分别在海口火山和珠江口盆地下方．（3）对V_p和V_s及据其算出的容声速度V_b作分析发现，V_s和V_b的平均扰动量对深度的变化在一些深度范围内是反向的；年龄较大的太平洋板块俯冲体的V_s相对扰动量的平均值大于V_b的，而在较年轻的PHP俯冲体中则正好相反．  相似文献   

叠层橡胶垫基础隔震建筑结构设计方法与应用     

孙柏锋  潘文 《世界地震工程》2007,23(4):139-142

简要概括了国内外叠层橡胶垫基础隔震技术的应用发展状况，介绍了隔震结构的各种反应分析模型，对隔震结构设计分析方法进行了讨论，提出了有益的建议，并指出了在《建筑抗震设计规范》（GB50011-2001）关于隔震结构的简化计算方法中存在的诸多不足。结合我国的隔震技术应用现状，引入了两阶段设计法的概念。此方法将有利于提高设计质量，减少设计周期。  相似文献   

A non‐baseline algorithm for damage locating in flexural structures using dynamic distributed macro‐strain responses     

S. Z. Li  Z. S. Wu 《地震工程与结构动力学》2007,36(9):1109-1125

The concept of distributed strain‐sensing techniques has been proposed in our recent research, which was dedicated to utilizing the strain distributions throughout the full or partial areas of structures to detect arbitrary and unforeseen damage. An algorithm not requiring a detailed analytical model is presented for damage locating in flexural structures through the direct use of dynamic responses recorded by distributed long‐gauge strain sensors. The modal macro‐strain vector (MMSV), which has been proven to have a mapping relation with displacement mode shape, can be extracted directly from macro‐strain time‐series data, from which a damage evaluating index can be derived and used as an indicator for locating damage. Numerical examples are simulated to verify the sensitivity and effectiveness of the index in different cases. Furthermore, experimental investigations on a cantilevered beam with various long‐gauge fibre optic sensors placements are carried out to examine the feasibility and applicability of the proposed method. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献