Non-double-couple mechanisms in the seismicity preceding the 1991–1993 Etna volcano eruption     

A. Saraò  G. F. Panza  E. Privitera  O. Cocina 《Geophysical Journal International》2001,145(2):319-335

  相似文献   

Point Sources of Elastic Deformation: Elementary Sources, Static Displacements   总被引：1，自引：0，他引：1  

Y. Y. Kagan 《Geophysical Journal International》1987,90(1):1-34

Summary. We construct a catalogue of all possible elementary point sources for static deformation in an elastic solid. the familiar double-couples, CLVD's, centres of compression and dilatation, etc., are all members of the complete catalogue. the sources are classified according to the rank of the seismic moment tensor, and according to the weight (or order) of the irreducible tensor representation of the 3-D rotation group. These sources can be classified as belonging to one of three general classes. the static excitation functions are calculated for an infinite, homogeneous, isotropic medium for all these sources. We show that, except for sources belonging to these three general classes, all other sources — which are numerous for the tensors of high rank — are null static sources. That is, sources that do not produce any static displacement outside of the source region. Due to the presence of null sources, an inversion of the static deformation data is non-unique. the expansion of the equivalent-force tensors and the stress glut tensors (or seismic moment tensors) into a set of the symmetric trace-free source tensors is proposed. the sources corresponding to seismic moment tensors of the second, third and fourth ranks are considered in more detail. We identify the third-rank sources with rotational dislocations or disclinations.  相似文献   

Crustal deformation in northern Central America     

Diego Cceres  David Monterroso  Behrooz Tavakoli 《Tectonophysics》2005,404(1-2):119-131

Evaluation of the seismic moment tensor for earthquakes on plate boundary is a standard procedure to determine the relative velocity of plates, which controls the seismic deformation rate predicted from the slip on a single fault. The moment tensor is also decomposed into an isotropic and a deviatoric part to discover the relationship between the average strain rate and the relative velocity between two plates. We utilize this procedure to estimate the rates of deformation in northern Central America where plate boundaries are seismically well defined. Four different tectonic environments are considered for modelling of the plate motions. The deformation rates obtained here compare well with those predicted from the plate motions models and are in good agreement with actual observations. Deformation rates on faults are increasingly being used to estimate earthquake recurrence from information on fault slip rate and more on how we can incorporate our current understanding into seismic hazard analyses.  相似文献   

2004年12月26日印尼北苏门答腊以西近海Ms9.0地震与地震的类临界点模型   总被引：3，自引：1，他引：3       下载免费PDF全文

蒋长胜  吴忠良 《地震学报》2005,27(3):269-275

使用哈佛CMT资料， 研究了2004年12月26日印尼北苏门答腊以西近海MW9.0地震前的长期地震活动. 这次地震前， 在1/4世纪的时间尺度、 1 500 km的空间尺度上， 存在加速矩释放（AMR）现象. 在这一空间尺度范围内，MW9.0地震仍落在分段的幂律分布上. 因此, 从地震的类临界点模型的角度考虑， 对这次特大地震的发生和地震的大小既无预测、 亦无预报的情况， 并非由物理上的ldquo;不可预测性rdquo;所致.   相似文献   

On the Consistency of Large Earthquake Moment and Strain Rate Inferred from GPS Data in North China   总被引：2，自引：0，他引：2  

Wan Yongge 《中国地震研究》2005,19(3):249-258

INTRODUCTIONStudyingthe relation between the accumulation of crustal strain and the release rate of seismicmoment is animportant subject of earth science research.It is also one of the important methods ofestimatingthe future seismic risk(Ward,1994;1998a;…  相似文献   

Moment tensor inversion and source rupture process of the September 27, 2003 M_S=7.9 earthquake occurred in the border area of China, Russia and Mongolia   总被引：1，自引：0，他引：1  

赵翠萍  陈章立  郑斯华  刘杰 《地震学报(英文版)》2005,18(3)

IntroductionOn September 27, 2003, an earthquake of MS=7.9 struck the border area of China, Russia and Mongolia. According to the field investigation from the Earthquake Administration of XinjiangAutonomous Region, the whole northern Tianshan region felt the hit. Buildings and structures within six counties and one city in Altay region, which is total about 0.11×106 km2 area, were damaged to different extent and caused certain economic losses. The epicenter determined by China National …  相似文献   

Image Zernike Moments Shape Feature Evaluation Based on Image Reconstruction     

LIU Maofu HE Yanxiang YE Bin 《地球空间信息科学学报》2007,10(3):191-195

  相似文献   

Radiative transfer theory for estimation of the seismic moment     

C. Sens-Schönfelder  U. Wegler 《Geophysical Journal International》2006,167(3):1363-1372

  相似文献   

Inclusion of P–Δ effect in displacement‐based seismic design of steel moment resisting frames     

Aristidis V. Asimakopoulos  Dimitris L. Karabalis  Dimitri E. Beskos 《地震工程与结构动力学》2007,36(14):2171-2188

A procedure for treating the P– Δ effect in the direct displacement‐based seismic design of regular steel moment resisting frames with ideal elastoplastic material behaviour is proposed. A simple formula for the yield displacement amplification factor as a function of ductility and the stability coefficient is derived on the basis of the seismic response of an inelastic single degree‐of‐freedom system taking into account the P– Δ effect. Extensive parametric seismic inelastic analyses of plane moment resisting steel frames result in a simple formula for the dynamic stability coefficient as a function of the number of stories of a frame and the column to beam stiffness ratio. Thus, the P– Δ effect can be easily taken into account in a direct displacement‐based seismic design through the stability coefficient and the yield displacement amplification factor. A simple design example serves to illustrate the application of the proposed method and demonstrate its merits. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Artificial neural network application to estimate kinematic soil pile interaction response parameters   总被引：1，自引：0，他引：1  

Irshad Ahmad  M. Hesham El Naggar  Akhtar Naeem Khan   《Soil Dynamics and Earthquake Engineering》2007,27(9):892-905

Six artificial neural network (ANN) models are developed to predict various response parameters of kinematic soil pile interaction. These responses include (1) kinematic response factors for free and fixed head piles in homogenous soil layer to derive foundation input motion (2) normalized bending moment at fixed head of pile in homogenous soil layer (3) normalized kinematic pile moment at the interface of two soil layers of sharply different soil stiffnesses. These ANN models represent simple solutions that can be implemented in a simple calculator capable of matrix operation and bypass the site response analysis and the complex wave diffraction analysis. The data required for ANN training is generated using beam on dynamic Winkler formulation (BDWF). Fifty percent of the data is used to train the ANN models while remaining 50% is used to test the ANN models. The trained ANN models show good agreement with BDWF results.  相似文献