Stable inversions for complete moment tensors   总被引：5，自引：0，他引：5  

Sarah E. Minson  Douglas S. Dreger 《Geophysical Journal International》2008,174(2):585-592

The seismic moment tensors for certain types of sources, such as volcanic earthquakes and nuclear explosions are expected to contain an isotropic component. Some earlier efforts to calculate the isotropic component of these sources are flawed due to an error in the method of Jost & Herrmann. We corrected the method after Herrmann & Hutchensen and found great improvement in the recovery of non-double-couple moment tensors that include an isotropic component. Tests with synthetic data demonstrate the stability of the corrected linear inversion method, and we recalculate the moment tensor solutions reported in Dreger et al. for Long Valley caldera events and Dreger & Woods for Nevada Test Site nuclear explosions. We confirm the findings of Dreger et al. that the Long Valley volcanic sources contain large statistically significant isotropic components. The nuclear explosions have strikingly anomalous source mechanisms, which contain very large isotropic components, making it evident that these events are not tectonic in origin. This indicates that moment tensor inversions could be an important tool for nuclear monitoring.  相似文献   

朝阳地震台水管倾斜仪异常核实的认识和讨论     

吴庆明  贾晓东  赵永志  战晓芳  白琳 《防灾减灾学报》2015,(3):105-107

通过朝阳地震台水管倾斜仪异常调查核实,分析其可能的干扰源,并利用滤波和周期分析的数据分析方法进行验证,提高了前兆异常核实的信度和科学含量。  相似文献   

三山岛断裂在海域北延位置的确定及成矿预测   总被引：1，自引：0，他引：1  

王金辉  田京祥 《地质学报》2017,91(12):2771-2780

胶东金矿集中区是中国最重要的黄金基地,三山岛金矿带位于该金矿集中区之胶西北成矿区的西部,近年来深部和海域隐伏区找矿取得重大突破。作为该区域重要的赋矿构造,三山岛断裂带进入海域后向两端延伸位置未能确定。为了查明三山岛断裂在南北两端进入海域后的延展位置,使用海底重力仪开展了海上大比例尺重力测量工作,对其位置进行了推断。在布伽重力异常图上,三山岛断裂表现为规模大、水平变化率大的重力梯级带,在平面上呈"S"形,向北由三山岛金矿延伸入海,向南从新立西延入渤海,跨海后经仓上、潘家屋子东延入渤海。为了确定三山岛断裂带向北东方向穿过三山岛北部海域超大型金矿床后的延展位置,根据重力异常推断的三山岛断裂北延位置,结合该金成矿带地质矿产特征,部署钻孔进行验证。钻孔内主要岩性有中细粒(含黑云母)二长花岗岩、钾化二长花岗岩、碎裂状二长花岗岩、绢英岩化花岗岩等,暗色脉岩有辉长岩及少量黑云母闪长岩、闪长玢岩等,其中暗色矿物黑云母等略具定向排列,脉岩均发生不同程度的蚀变。构造蚀变(矿化)带宽206.25m(876.59~1082.84m),与上盘围岩分界较为清楚,与下盘围岩呈渐变关系,圈定7层矿体,累计厚度28.3m,最厚的单层矿体视厚度16.06m。钻孔位置位于重力梯度变化宽缓的"鼻状区",且空间位置符合等距分布、对应产出、分段富集等分布规律,钻孔中见到多为黄铜矿化、方铅矿、黄铁矿等多金属硫化物矿化,为典型的第一矿集群特征,可以确定该地区继三山岛北部海域470吨超大型金矿发现之后,其北部区域又出现一个很有找矿前景的靶区。  相似文献   

Reliability bearing capacity analysis of footings on cohesive soil slopes using RFEM     

《Computers and Geotechnics》2017

Reliability analysis of bearing capacity of a strip footing at the crest of a simple slope with cohesive soil was carried out using the random finite element method (RFEM). Analyses showed that the coefficient of variation and the spatial correlation length of soil cohesion can have a large influence on footing bearing capacity, particularly for slopes with large height to footing width ratios. The paper demonstrates cases where a footing satisfies a deterministic design factor of safety of 3 but the probability of design failure is unacceptably high. Isotropic and anisotropic spatial variability of the soil strength was also considered.  相似文献   

Research on the Historical Data of the 1585 A. D. South Chaoxian Earthquake and Its Seismogenic Structure     

Zhai Hongtao  Deng Zhihui  Zhou Bengang  Li Guang  Zheng Yingpin 《中国地震研究》2010,24(1):106-116

In 1585, a Ms53/4 earthquake occurred in the south of Chaoxian county, Anhui Province. The parameters of this earthquake were reported differently in various versions of earthquake catalogues. According to detailed textual research on the historic records of this earthquake, the epicenter location of the earthquake was further confirmed by means of seismo-geological field investigations in the Chaohu-Tongling region along the western Yangtze River valleys. Shallow seismic prospecting and drilling methods were applied in studying the buried fault. The possibility of the existence of seismogenic faults and fault activity in the western Yangtze River area were analyzed in depth, and the causative tectonic background of the 1585 Ms53/4 south Chaoxian earthquake was studied. The results of this study indicate that the Yanjiaqiao-Fengshahu fault, which was active in the early to mid-Pleistocene, is possibly the causative structure of this earthquake.To identifying the seismogenic structure of the 1585 south Chaoxian earthquake will help gain more knowledge about the tectonic background of moderate and small earthquake activity in Eastern China.  相似文献   

石家庄铁四局北国-开元广场岩土工程勘察实录     

梁金国  田鹏程  周文生 《岩土工程技术》2009,23(3):159-162,F0003

通过石家庄铁四局北国-开元广场工程勘察实例介绍,总结出一套成功进行岩土工程分析的有效办法和技术途径,分析结果通过实测验证,可供同行们参考。  相似文献   

考虑湿化效应的堆石料Gudehus-Bauer 亚塑性模型应用研究     

岑威钧  Erich Bauer  Sendy F.Tantono 《岩土力学》2009,30(12):3808-3812

在扼要分析堆石料主要力学特性的基础上,在亚塑性理论框架内,采用扩展的Gudehus-Bauer亚塑性模型对堆石料因含水率发生变化引起的湿化行为进行建模预测。扩展模型除能考虑含水率对颗粒硬度的影响外,还能反映土体密实度、应力状态和含水率等对堆石料非线性和非弹性变形的影响。将该模型应用于心墙坝初次蓄水时应力变形的亚塑性计算分析中。结果表明,扩展模型能较合理地反映心墙堆石坝的湿化变形规律。  相似文献   

Comparison of adaptive structural damage identification techniques in nonlinear hysteretic vibration isolation systems     

Tengfei Mu  Li Zhou  Jann N. Yang 《地震工程与工程振动(英文版)》2013,12(4):659-667

Early structural damage identification to obtain an accurate condition assessment can assist in the reprioritization of structural retrofitting schedules in order to guarantee structural safety. Nowadays, seismic isolation technology has been applied in a wide variety of infrastructure, such as buildings, bridges, etc., and the health conditions of these nonlinear hysteretic vibration isolation systems have received considerable attention. To effectively detect structural damage in vibration isolation systems based on vibration data, three time-domain analysis techniques, referred to as the adaptive extended Kalman filter （AEKF）, adaptive sequential nonlinear least-square estimation （ASNLSE） and adaptive quadratic sum-sqnares error （AQSSE）, have been investigated. In this research, these analysis techniques are compared in terms of accuracy, convergence and efficiency, for structural damage detection using experimental data obtained through a series of laboratory tests based on a base-isolated structural model subjected to E1 Centro and Kobe earthquake excitations. The capability of the AEKF, ASNLSE and AQSSE approaches in tracking structural damage is demonstrated and compared.  相似文献   

Verification and validation of a seismic response analysis code for framed structures using the ASI‐Gauss technique     

Daigoro Isobe  Won Sang Han  Tomoshi Miyamura 《地震工程与结构动力学》2013,42(12):1767-1784

In this report, the capabilities of the adaptively shifted integration (ASI)‐Gauss code in the analysis of the seismic responses of framed structures are verified and validated by comparing the results with detailed numerical simulations performed by the parallel finite element analysis code, E‐Simulator, and with experimental results obtained by E‐Defense. The numerical results obtained by both codes showed good agreement with the experimental results obtained by E‐Defense. Furthermore, seismic waves with unnaturally large magnitudes are applied to a high‐rise building model to demonstrate the ability of the ASI‐Gauss code to analyze the collapse behaviors of building frames. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Investigation of the groundwater modelling component of the Integrated Water Flow Model (IWFM)     

Ali Ercan  Emin C. Dogrul  Tariq N. Kadir 《水文科学杂志》2013,58(16):2834-2848

ABSTRACT

The Integrated Water Flow Model (IWFM), developed by the California Department of Water Resources, is an integrated hydrological model that simulates key flow processes including groundwater flows, streamflow, stream–aquifer interactions, rainfall–runoff and infiltration. It also simulates the agricultural water demand as a function of soil, crop and climatic characteristics, as well as irrigation practices, and allows the user to meet these demands through pumping and stream diversions. This study investigates the modelling performance of the groundwater module of IWFM using several hypothetical test problems that cover a wide range of settings and boundary conditions, by comparing the simulation results with analytical solutions, field and laboratory observations, or with results from MODFLOW outputs. The comparisons demonstrate that IWFM is capable of simulating various hydrological processes reliably.