基于GPS、水准和强震动观测资料联合反演2013年芦山7.0级地震同震滑动分布          下载免费PDF全文

刘琦  闻学泽  邵志刚 《地球物理学报》2016,59(6):2113-2125

为了更好理解2013年四川芦山M_S7.0级地震的发生过程及其与发震构造和地表多种观测资料的动力学关联,本文综合重新定位的余震分布与地质、地球物理信息构建3D发震构造模型,采用水平层状介质模型,并以震区GPS、水准、强震动等同震位移/形变观测资料为约束,联合反演了芦山主震的同震滑动分布.其中,断层解译结果表明震源区包含5条相关断层F1-F5,通过对所有可能的断层组合模型进行反演分析,显示采用F1+F3+F4+F5的组合模型反演效果相对最好,是最可能的发震断层模型.反演得到的芦山主震矩震级为M_W6.5,其中同震滑动主要分布在NW倾的主断层F1的断坡周围,最大值为0.86 m,滑动角92.88°,纯逆冲型;F1上方反倾的次级断层F3上最大滑动量为0.37 m,滑动角119.92°,表现出以逆冲为主兼右滑的斜向反冲作用;而沿另一条反倾的次级断层F4的最大滑动量为0.40 m,滑动角97.98°,几乎为纯逆冲作用.此外,震区还存在一个NW缓倾深度为5~8 km的浅部滑脱面F5,它分隔了浅部沉积盖层与深部变质基底,限制了其下方F1、F3及F4等断层的同震破裂继续向更浅部扩展.主震时深部F1和F3断层夹持的冲起构造发生了上冲运动,除了使浅层和地表产生响应运动及变形外,还引起冲起构造顶面即F5底面的NE段和SW段分别产生了NE和SWW向调节滑动,最大值0.25 m.总之,基于文中构建的F1+F3+F4+F5的发震断层模型,反演结果能很好拟合地表多种观测资料,还能解释地表GPS观测的同震"左旋"运动与地震学观测的震源断层逆冲运动的"不协调性".  相似文献   

基于Russell近似的纵横波联合反演方法研究   总被引：1，自引：1，他引：0       下载免费PDF全文

杜炳毅  杨午阳  王恩利  王洪求  李海山  鄢高韩 《地球物理学报》2016,59(8):3016-3024

PP波和PS波联合反演方法作为有效的地震技术,比单纯纵波反演精度要高,能够提高地震储层识别的精度.以Russell近似理论为基础,推导了新的转换波AVO近似公式,双层模型界面的反射特征数值模拟显示,新公式具有较高的近似精度,且具备直接反演流体因子f、剪切模量μ和密度ρ等参数的优势,有效避免间接反演带来的误差.结合纵横波联合反演理论,提出了基于贝叶斯理论的新型联合反演算法.在实际应用中,对纵波和转换波角道集进行同相轴匹配处理,综合利用纵波和转换波资料携带的信息,实现基于Russell近似的多波联合反演.模型数据和实际资料测试结果表明,反演结果与真实值或测井结果匹配度较高,证实该方法真实有效.  相似文献   

基于贝叶斯理论的接收函数与环境噪声联合反演   总被引：11，自引：5，他引：6       下载免费PDF全文

刘启元  李昱  陈九辉  郭飚  王峻  齐少华  李顺成 《地球物理学报》2010,53(11):2603-2612

基于Bayes反演理论(Tarantola,1987,2005),在接收函数非线性复谱比反演方法基础上(刘启元等,1996),本文讨论了接收函数与地震环境噪声Rayleigh波相速度频散的联合反演.本文采用修正后的快速广义反射/透射系数方法(Pei et al., 2008,2009) 计算Rayleigh波相速度频散, 并引入地壳泊松比的全局性搜索.数值检验表明:(1)接收函数与环境噪声的联合反演能够有效地解决反演结果对初始模型依赖的问题,即使对地壳速度结构仅有非常粗略的初始估计(例如,垂向均匀模型),本文方法仍能给出模型参数的可靠估计;(2)由于环境噪声与接收函数在频带上的适配性明显优于地震面波,接收函数与环境噪声的非线性联合反演能更好地约束台站下方近地表的速度结构;对于周期范围为2~40s的环境噪声相速度频散,利用本文方法能够可靠推测台站下方0~80 km深度范围的S波速度结构, 其浅表速度结构的分辨率可达到1 km; (3)本文方法能够可靠地估计地壳泊松比,泊松比的全局性搜索有助于合理解释接收函数和环境噪声的面波频散数据.利用本文方法对川西台阵KWC05台站观测的接收函数与环境噪声的联合反演表明,该台站下方地壳厚度为44 km,上地壳具有明显的高速结构,24~42 km范围的中下地壳具有低速结构.该台站下方地壳的平均泊松比为0.262,壳内低速带的泊松比为0.27.  相似文献   

Statistical simulation of wave climate and extreme beach erosion     

D.P. Callaghan  P. Nielsen  A. Short  R. Ranasinghe 《Coastal Engineering》2008

Recent developments in extreme values modelling have been used to develop a framework for determining the coastal erosion hazard on sandy coastlines. This framework quantitatively reproduced the extreme beach erosion volumes obtained from field measurements at Narrabeen Beach, Australia. This encouraging finding was achieved using Kriebel and Dean's [Kriebel, D.L. and Dean, R.G., 1993. Convolution method for time-dependent beach profile response. Journal of Waterway, Port, Coastal and Ocean Engineering, 119(2): 204–226.] simple beach erosion and accretion model. The method includes allowances for joint probability between all basic erosion variates including; wave height, period and direction, event duration, tidal anomalies and event spacing. A new formulation for the dependency between wave height and period has been developed. It includes the physical wave steepness limitation. Event grouping, where significantly more erosion can occur from two closely spaced storms is handled by temporally simulating the synthetic wave climate and the resulting beach erosion and accretion.  相似文献   

节理统计锥体单元法的探讨     

李巍然 《中国海洋大学学报(自然科学版)》1993,(Z1)

本文提出在投影球内建立锥体单元统计系统,直接计算以产状表示的单元轴线与节理法线的夹角,统计该夹角小于单元锥角半角的数目。统计结果更合理、可靠。  相似文献   

二阶非线性随机海浪波面高度和波面垂直速度的联合分布     

管长龙 《海洋与湖沼》1997,28(5):503-508

基于Longuet－Higgins提出的非线性随机海浪模型，在二阶近似下通过直接计算联合分布的各阶矩，导出了非线性海浪波面高度和波面垂直速度的联合分布。该分布为非正态，其形式为截断的级数，而非由累积矩母函数方法可能得到的渐近无穷级数。由于非线性的影响，波面高度与波面垂直速度不再相互独立。  相似文献   

Joint probability analysis of water and sediment and predicting sediment load based on copula function     

《国际泥沙研究》2022,37(5):639-652

The Jinsha River comprises the upper reaches of the Yangtze River, which is the river section with the highest sediment content. Monitoring of sediment transport in the Jinsha River is done to the guarantee for the normal operation of the Three Gorges Reservoir. In the current study, a copula function was used to do a joint probability analysis of the water and sediment in the Jinsha River Basin (JRB), further a sediment load prediction model based on the copula function also was constructed. The results show that the average annual flow from 2001 to 2018 at the outlet of the Jinsha River (Yibin station) is about 60.43 billion m³, and the average annual sediment load is about 58.82 million t. The linear correlation coefficient between annual flow and annual sediment load is 0.28. The best marginal distribution for annual flow and sediment load is Pearson Type Three (PE3) and Generalized Normal (GNO), respectively, and the best fit for the combined distribution of the two variables is the Frank copula function. The synchronous probability of water and sediment occurrence is 0.459, and the asynchronous probability is 0.541. Based on the copula prediction model, the sediment load can be effectively simulated, and the correlation coefficient between the simulated sequence and the measured sequence reached 0.93. The current study provides important significance for the analysis of water and sediment in the JRB, which is beneficial to the management of Three Gorges Reservoir sediment discharge in the upstream and downstream.  相似文献   

Influence of rock property correlation on reliability analysis of rock slope stability: From property characterization to reliability analysis     

《地学前缘(英文版)》2018,9(6):1639-1648

Cohesion(c) and friction angle(φ) of rock are important parameters required for reliability analysis of rock slope stability. There is correlation between c and φ which affects results of reliability analysis of rock slope stability. However, the characterization of joint probability distribution of c and φ through which their correlation can be estimated requires a large amount of rock property data, which are often not available for most rock engineering projects. As a result, the correlation between c and φ is often ignored or simply assumed during reliability studies, which may lead to bias estimation of failure probability. In probabilistic rock slope stability analysis, the influence of ignoring or simply assuming the correlation of the rock strength parameters(i.e., c and φ) on the reliability of rock slopes has not been fully investigated. In this study, a Bayesian approach is developed to characterize the correlation between c and φ, and an expanded reliability-based design(RBD) approach is developed to assess the influence of correlation between c and φ on reliability of a rock slope. The Bayesian approach characterizes the sitespecific joint probability distribution of c and φ, and quantifies the correlation between c and φ using available limited data pairs of c and φ from a rock project. The expanded RBD approach uses the joint probability distribution of c and φ obtained through the Bayesian approach as inputs, to determine the reliability of a rock slope. The approach gives insight into the propagation of the correlation between c and φ through their joint probability into the reliability analysis, and their influence on the calculated reliability of the rock slope. The approaches may be applied in practice with little additional effort from a conventional analysis. The proposed approaches are illustrated using real c and φ data pairs obtained from laboratory tests of fractured rock at Forsmark, Sweden.  相似文献   

水库泄洪方式对白洋淀入淀洪水及防洪的影响分析          下载免费PDF全文

毛慧慧  张建中 《水文》2018,38(4):83-86

以海河流域大清河南支为研究对象,基于2016年设计洪水修订成果,计算了100年一遇标准洪水,白洋淀上游5座大型水库在分级控泄调度、峰后敞泄调度、联合调度3种调度方式下,入白洋淀的洪水过程线,以此为基础,计算了各种水库调度方式对白洋淀蓄滞洪区防洪的影响。  相似文献   

虚拟地理环境视景研究     

邹逸江  吴金华 《地球科学与环境学报》2002,24(2):68-71

叙述了如何生成基于真实地形数据的、具有逼真地球表面文化特征和自然景象的虚拟地理环境视景,主要论述了虚拟地理环境视景生成平台的构成、设计、模型的构建、离散模型的连接组合、光照技术、天空模型、特殊效果的绘制、分割调度的应用等技术。  相似文献