中国大陆活动断裂的段破裂地震复发行为

为了考察中国大陆活动断裂带段破裂地震的复发行为,根据多轮回复发的地震资料定量分析了19个断裂段的地震历史．结果表明:这些断裂段的地震原地复发主要表现出:① 良好的准周期行为(约占9/19);② 时间可预报行为(约占12/19)．第1种行为的复发间隔内在不确定性为平均间隔的0.15～0.40,不同轮回事件的震级在平均震级0.5级之内变化．第2种行为的复发间隔内在不确定性大多为平均间隔的0.19～0.40,相继轮回事件的最大震级差可达1.7级．另外,少数情况下第1种行为可与第2种或者滑动可预报行为共存．      

甘孜-玉树断裂的平均滑动速率与近代大地震破裂

野外调查获得甘孜-玉树断裂晚第四纪活动及近代地震破裂的新证据,由7个地点的断错地貌及其相关沉积物年龄确定出近5万年来断裂的平均左旋滑动速率(122)mm/a,该结果与鲜水河断裂的平均左旋滑动速率估值很接近,反映了沿川滇～羌塘活动地块的北～东北边界的晚第四纪水平运动总体上是协调的,沿断裂的3个段落均发现近代大地震地表破裂的遗迹,其中,北西段1896年破裂至少长70km,相应地震的矩震级为7.3;中段的最新破裂长约180km,是一次矩震级约为7.7、未知年代的大地震形成的;东南段未知年代的最新破裂长约65km,最大同震左旋位移5.3m,估计相应地震的矩震级约为7.3,已根据调查资料推断了后两次大地震可能分别发生在1854年和1866年,这些证明该断裂的不同段落均具有发生大地震的能力。     

东昆仑断裂带中东部地震破裂分段性与走滑运动分解作用

基于卫星影像解译和野外考察测量,本文对东昆仑断裂带中东部的3条次级断裂(托索湖断裂、玛沁断裂和玛曲断裂)的滑动速率以及全新世以来的古地震活动特征进行了分析研究。托索湖段与玛沁段走向产生20°和30°的双挤压弯曲,形成阿尼玛卿山挤压隆起,作为托索湖段和玛沁段的破裂分段标志,成为1937年托索湖7.5级地震地表破裂带的终止点;在西贡周西侧和莫哈塘南侧,阿万仓断裂以40°的夹角与东昆仑断裂带相交,形成西贡周断裂交汇区,成为玛沁段与玛曲段破裂分段的标志。通过构造地貌方法获得西段托索湖断裂晚第四纪晚期以来的平均水平速率为10.8±1mm/a,垂直滑动速率为1.2±0.2mm/a;中段玛沁断裂带晚第四纪晚期以来的平均水平滑动速率为9.3±2mm/a,垂直滑动速率为0.7±0.1mm/a;西贡周断层交汇区平均水平滑动速率为7.4±1mm/a,垂直滑动速率为1.2±0.1mm/a;东段玛曲断裂晚第四纪晚期以来的平均水平滑动速率为4.9±1.3mm/a,垂直滑动速率为0.3mm/a。断裂的滑动速率从西至东呈梯度下降,通过构造转换矢量分解获得阿万仓断裂西支的左旋水平走滑速率为2.4mm/a,东支的左旋水平走滑速率为1.4mm/a,垂直断裂的水平缩短速率为2.3mm/a,阿万仓断裂带西支和东支构成一个滑动分解模式。3条次级断裂的活动均产生独立地表破裂,西侧的托索湖断裂发生了1937年MS7.5级地震,中段玛沁断裂发生了公元1061年格萨尔王时期和距今358~430CalaBP的地表破裂,玛曲段地表破裂距今约1055~1524aBP,显示出段落之间应力触发有关的地震破裂事件沿断裂带单向迁移的特征。同时利用断裂单次地震位移和古地震复发周期获得断裂的长期滑动速率,结果显示与构造地貌方法获得的滑动速率几乎一致,也显示自西向东逐渐递减的趋势。断裂滑动速率的递减与几何结构走向的弯曲以及横向断裂的相交一一对应,东昆仑断裂带的滑动速率梯度递减的主要原因是东昆仑断裂带东延和横向断裂相交,构造转换造成的。     

鲜水河断裂带北西段不同破裂源强震震级（M≥67）及复发间隔研究

鲜水河断裂带是四川西部一条晚第四纪强烈左旋走滑活动的构造带，历史上发生多次强震. 它与西北侧的甘孜—玉树断裂带一起，构成青藏高原东部的侧向滑移构造系统中的川滇活动地块的北边界——羌塘地块的东北边界. 鲜水河断裂带北西段可以分成4个段落，每一段落均可作为一个独立的基本破裂单元而发生地震破裂，亦有可能发生不同尺度的多段联合瞧裂. 对鲜水河断裂带北西段不同尺度破裂的震级及复发间隔进行研究. 根据该地区的地质、地球物理、测量及地震等方面的资料，结合我国强震复发的特点，分析了拉分盆地内部的滑动速率分布，以确定各段落的等效长度和倾向宽度，从而建立适合我国大陆走滑断裂的面波震级与断裂发震面积的关系式；进而运用地震矩方法，考虑断层之间的相互作用，结合专家意见建立了该段的矩平衡断裂破裂模型；最后，给出了鲜水河断裂带北西段各破裂源特征化地震的复发间隔、震级大小和不确定性，以及他与中小地震的联合震级分布. 结果表明，鲜水河断裂带北西段较易发生单段破裂，复发间隔在100～150年左右.     

鲜水河断裂带北西段不同破裂源强震震级（M≥67）及复发间隔研究

鲜水河断裂带是四川西部一条晚第四纪强烈左旋走滑活动的构造带，历史上发生多次强震. 它与西北侧的甘孜—玉树断裂带一起，构成青藏高原东部的侧向滑移构造系统中的川滇活动地块的北边界——羌塘地块的东北边界. 鲜水河断裂带北西段可以分成4个段落，每一段落均可作为一个独立的基本破裂单元而发生地震破裂，亦有可能发生不同尺度的多段联合瞧裂. 对鲜水河断裂带北西段不同尺度破裂的震级及复发间隔进行研究. 根据该地区的地质、地球物理、测量及地震等方面的资料，结合我国强震复发的特点，分析了拉分盆地内部的滑动速率分布，以确定各段落的等效长度和倾向宽度，从而建立适合我国大陆走滑断裂的面波震级与断裂发震面积的关系式；进而运用地震矩方法，考虑断层之间的相互作用，结合专家意见建立了该段的矩平衡断裂破裂模型；最后，给出了鲜水河断裂带北西段各破裂源特征化地震的复发间隔、震级大小和不确定性，以及他与中小地震的联合震级分布. 结果表明，鲜水河断裂带北西段较易发生单段破裂，复发间隔在100～150年左右.     

中甸-大具断裂南东段晚第四纪活动的地质地貌证据

中甸-大具断裂南东段位于哈巴和玉龙雪山北麓,属于川西北次级块体西南边界,断裂总体走向310°~320°,是一条重要的边界断裂。了解该断裂的活动性质、活动时代和滑动速率等对分析川西北次级块体运动,研究该断裂与玉龙雪山东麓断裂的交切关系等问题具有重要意义。文中基于1︰5万活动断层地质填图,对断裂沿线地层地貌、陡坎地貌、地表破裂、典型断层剖面以及河流阶地等进行了详细的研究。研究表明:1)中甸-大具断裂南东段按几何结构、断错地貌表现、断裂活动性可分为马家村—大具次级段和大具—大东次级段。2)通过野外地质调查发现,马家村—大具次级段断错了全新世冲洪积扇,形成了地表破裂,为全新世活动段;而大具—大东次级段虽然也断错了晚更新—全新世地层,但其断错规模及滑动速率均较小,由此认为其全新世以来活动较弱。3)通过分析断裂沿线断层陡坎、水平位错及地表破裂等地质地貌问题,认为马家村—大具次级段的活动性质为右旋走滑兼正断,其晚更新世以来的垂直滑动速率为0.4~0.8mm/a,水平滑动速率为1.5~2.4mm/a;大具—大东次级段以右旋走滑为主、正断为辅,其晚更新世晚期以来的垂直滑动速率为0.1mm/a。4)在大具盆地内发现的NW向地表破裂带的形成时代很年轻,不排除是1966年中甸6.4级地震或1996年丽江7.0级地震造成的地表破裂。     

中旬-大具断裂南东段晚第四纪活动的地质地貌证据

中甸-大具断裂南东段位于哈巴和玉龙雪山北麓,属于川西北次级块体西南边界,断裂总体走向310°～320°,是一条重要的边界断裂。了解该断裂的活动性质、活动时代和滑动速率等对分析川西北次级块体运动,研究该断裂与玉龙雪山东麓断裂的交切关系等问题具有重要意义。文中基于1︰5万活动断层地质填图,对断裂沿线地层地貌、陡坎地貌、地表破裂、典型断层剖面以及河流阶地等进行了详细的研究。研究表明:1)中甸-大具断裂南东段按几何结构、断错地貌表现、断裂活动性可分为马家村—大具次级段和大具—大东次级段。2)通过野外地质调查发现,马家村—大具次级段断错了全新世冲洪积扇,形成了地表破裂,为全新世活动段;而大具—大东次级段虽然也断错了晚更新—全新世地层,但其断错规模及滑动速率均较小,由此认为其全新世以来活动较弱。3)通过分析断裂沿线断层陡坎、水平位错及地表破裂等地质地貌问题,认为马家村—大具次级段的活动性质为右旋走滑兼正断,其晚更新世以来的垂直滑动速率为0. 4～0. 8mm/a,水平滑动速率为1. 5～2. 4mm/a;大具—大东次级段以右旋走滑为主、正断为辅,其晚更新世晚期以来的垂直滑动速率为0. 1mm/a。4)在大具盆地内发现的NW向地表破裂带的形成时代很年轻,不排除是1966年中甸6. 4级地震或1996年丽江7. 0级地震造成的地表破裂。     

三危山断裂敦煌段古地震活动特征

三危山断裂位于青藏高原北缘NW向扩展的前缘位置,其最新地震活动反映了高原北部地区的构造变形特征.文中通过遥感影像解译、野外实地调查、古地震探槽及光释光年代样品测试,对三危山断裂敦煌段的古地震活动特征开展了研究.结果表明,断裂晚更新世以来发生过2次古地震事件,事件E1发生的年代约为距今(35.1±3.7)～(36.7±4.1)ka;事件E2发生的年代约为距今(76.5±8.8)～(76.7±8.3)ka.三危山断裂晚更新世以来的垂直滑动速率为(0.03±0.01)mm/a,相应的缩短速率为(0.09±0.01)mm/a.综合前人的研究结果,认为三危山断裂的地震活动具有分段性特征,中段、东段可能具有独立破裂的能力,也存在与敦煌段发生级联破裂的特征,复发间隔约为40ka,根据经验公式估算三危山断裂可能发生的震级范围为MW7.1～7.5.     

东昆仑活动断裂带库赛湖段破裂行为及影响因素的初步研究

2001年11月14日,青藏高原北部东昆仑断裂带库赛湖段发生了MS8.1地震。此次地震的发震断裂在地质史上具有高速左旋滑动的特征,特别是晚更新世晚期以来库赛湖断裂的平均滑动速率达(14.8±2.8)mm/a。库赛湖断裂不同的滑动速率可能会对其未来发生的运动行为产生影响,为此文中研究了东昆仑活动断裂带库赛湖段不同滑动速率和不同断裂面初始摩擦系数对断裂破裂行为的影响,建立了库赛湖断裂段对应的速度和状态依赖摩擦定律控制的单自由度弹簧滑块模型。为得到合理的模型参数,模拟中采用了断裂位错模型,考察了相关古地震研究资料、历史地震资料以及前人的相关研究成果。通过模拟库赛湖断裂段在不同滑动速率下未来6ka的破裂行为,发现断裂滑动速率快可使地震复发周期缩短,滑动速率慢会使地震复发周期延长。例如,若断裂以现今平均14mm/a的初始滑动速率运动时,地震复发周期为2.1ka;若以18mm/a的初始滑动速率运动,其对应地震复发周期为1～1.5ka;而滑动速率为8mm/a时地震复发周期为2.1～2.5ka,但断裂滑动速率对地震发生时断裂错动的位移和错动速度没有规律性影响;断裂面初始摩擦系数的大小对地震复发周期有影响,初始摩擦系数较大可能会使地震周期减小,初始摩擦系数小可能会使地震复发周期增加;同时,断裂面初始摩擦系数较小可能会使地震发生时断裂错动的位移和错动速度变大。     

东昆仑断裂带中东部地震破裂分段性与走滑运动分解作用

基于卫星影像解译和野外考察测量,对东昆仑断裂带中东部托索湖段、玛沁段和玛曲段的晚更新世晚期以来滑动速率以及全新世以来的古地震活动特征进行了分析研究.阿尼玛卿山双挤压弯曲和西贡周断裂交汇区为这3条段落的破裂分段标志,也成为1937年托索湖7.5级地震地表破裂带的终止点.通过构造地貌方法获得这3条段落自西向东晚第四纪晚期以来的平均水平滑动速率分别为（11.2±1）,（9.3±2）和（4.9±1.3）mm/a;垂直滑动速率分别为（1.2±0.2）,（0.7±0.1）和0.3mm/a.断裂水平滑动速率从西至东呈梯度下降,递减的滑动速率主要转换到了与东昆仑断裂相交的阿万仓断裂上.通过构造转换矢量分解获得阿万仓断裂带西支和东支构成一个滑动分解模式,断裂西南盘相对北东盘的滑动速率为4.6mm/a,滑动方向为112.1°.3条段落的活动均产生独立地表破裂,西侧托索湖段1937年发生了M7.5级地震,往东玛沁段发生了514～534calaBP和距今（1070±180）a（格萨尔王时期）的地表破裂,玛曲段地表破裂发生在1055～1524aBP,显示出段落之间与应力触发有关的地震破裂事件沿断裂带单向迁移的特征.同时利用断裂单次地震位移和古地震复发周期获得断裂的长期滑动速率,结果显示与构造地貌方法获得的滑动速率几乎一致,也显示自西向东逐渐递减的趋势.断裂滑动速率的递减与几何结构走向的弯曲以及横向断裂的相交一一对应,因此东昆仑断裂带的滑动速率梯度递减的主要原因是东昆仑断裂带东延与横向断裂相交和构造转换所致.     

Assessing uncertainties in a conceptual water balance model using Bayesian methodology / Estimation bayésienne des incertitudes au sein d’une modélisation conceptuelle de bilan hydrologique

Abstract

Abstract The aim of this study was to estimate the uncertainties in the streamflow simulated by a rainfall–runoff model. Two sources of uncertainties in hydrological modelling were considered: the uncertainties in model parameters and those in model structure. The uncertainties were calculated by Bayesian statistics, and the Metropolis-Hastings algorithm was used to simulate the posterior parameter distribution. The parameter uncertainty calculated by the Metropolis-Hastings algorithm was compared to maximum likelihood estimates which assume that both the parameters and model residuals are normally distributed. The study was performed using the model WASMOD on 25 basins in central Sweden. Confidence intervals in the simulated discharge due to the parameter uncertainty and the total uncertainty were calculated. The results indicate that (a) the Metropolis-Hastings algorithm and the maximum likelihood method give almost identical estimates concerning the parameter uncertainty, and (b) the uncertainties in the simulated streamflow due to the parameter uncertainty are less important than uncertainties originating from other sources for this simple model with fewer parameters.     

核电厂考虑结构参数不确定的 地震易损性分析

为考虑核电厂结构参数不确定对结构地震易损性的影响,基于一次二阶矩法(First-Order Second-Moment, FOSM)进行地震易损性分析。以核电结构中混凝土材料的密度、弹性模量,泊松比和抗拉强度为不确定参数,建立有限元模型,并与试验结果对比,以验证模型的准确性。基于有限元数值模拟方法,通过增量动力法计算核电厂模型在多条地震记录下不同峰值加速度的动力响应,同时基于FOSM得到参数不确定下的对数标准差,进而得到核电厂结构考虑参数不确定的地震易损性曲线。结果表明,结构参数的不确定对核电结构有一定的影响,未考虑参数不确定的地震易损性结果会低估结构的失效概率。该方法可为核电结构基于参数不确定下的易损性分析提供一定的理论依据与实用价值。     

场地地震反应分析中的不确定性及其处理方法

系统地研究了场地地震反应分析中的不确定性及其产生的根源．利用蒙特卡洛法的有关理论,对影响场地地震反应分析结果的不确定性因素进行了估计与分析．实际应用结果表明,该方法是可行的,而且精度较高     

Stochastic Lagrangian trajectory model for drifting objects in the ocean

The prediction of drifting object trajectories in the ocean is a complex problem plagued with uncertainties. This problem is usually solved simulating the possible trajectories based on wind and advective numerical and/or instrumental data in real time, which are incorporated into Lagrangian trajectory models. However, both data and Lagrangian models are approximations of reality and when comparing trajectory data collected from drifter exercises with respect to Lagrangian models results, they differ considerably. This paper introduces a stochastic Lagrangian trajectory model that allows quantifying the uncertainties related to: (i) the wind and currents numerical and/or instrumental data, and (ii) the Lagrangian trajectory model. These uncertainties are accounted for within the model through random model parameters. The quantification of these uncertainties consists in an estimation problem, where the parameters of the probability distribution functions of the random variables are estimated based on drifter exercise data. Particularly, it is assumed that estimated parameters maximize the likelihood of our model to reproduce the trajectories from the exercise. Once the probability distribution parameters are estimated, they can be used to simulate different trajectories, obtaining location probability density functions at different times. The advantage of this method is that it allows: (i) site specific calibration, and (ii) comparing uncertainties related to different wind and currents predictive tools. The proposed method is applied to data collected during the DRIFTER Project (eranet AMPERA, VI Programa Marco), showing very good predictive skills.     

海啸危险性概率分析的不确定性研究

针对海啸危险性概率分析（PTHA）存在的较大不确定性问题,对不确定性产生来源进行了归纳和分类,提出了基于逻辑树与事件树方法合理量化不确定性的思路框架,并以马尼拉海啸潜源为研究对象,给出了量化震级上限、破裂面参数不确定的过程示例。数值模拟分析结果表明：海啸潜源震级上限的改变对危险性评估结果产生了显著影响,通过逻辑树方法可合理量化这种不确定性;地震破裂面的倾角、滑移角和破裂面积的随机不确定性对海啸危险性分析结果产生较为显著的影响,经事件树方法处理后的危险性结果保证率远高于20%,略低于80%,可基本满足工程抗海啸设计要求。     

Response uncertainty and time-variant reliability analysis for hysteretic MDF structures

Response uncertainty evaluation and dynamic reliability analysis corresponding to classical stochastic dynamic analysis are usually restricted to the uncertainties of the excitation. The inclusion of the parameter uncertainties contained in structural properties and excitation characteristics has become an increasingly important problem in many areas of dynamics. In the present paper, a point estimate procedure is proposed for the evaluation of stochastic response uncertainty, and a response surface approach procedure in standard normal space is proposed for analysis of time-variant reliability analysis for hysteretic MDF structures having parameter uncertainties. Using the proposed procedures, the response uncertainties and time-variant reliability can be easily obtained by several repetitions of stochastic response analysis under given parameters without conducting sensitivity analysis, which is considered to be one of the primary difficulties associated with conventional methods. In the time-variant reliability analysis, the failure probability can be readily obtained by improving the accuracy of the first-order reliability method using the empirical second-order reliability index. The random variables are divided into two groups, those with CDF and those without CDF. The latter are included via the high-order moment standardization technique. A numerical example of a 15F hysteretic MDF structure that takes into account uncertainties of four structural parameters and three excitation characteristics is performed, based on which the proposed procedures are investigated and the effects of parameter uncertainties are discussed. Copyright © 1999 John Wiley & Sons, Ltd.     

The probabilistic seismic hazard assessment of Germany—version 2016, considering the range of epistemic uncertainties and aleatory variability

The basic seismic load parameters for the upcoming national design regulation for DIN EN 1998-1/NA result from the reassessment of the seismic hazard supported by the German Institution for Civil Engineering (DIBt). This 2016 version of the national seismic hazard assessment for Germany is based on a comprehensive involvement of all accessible uncertainties in models and parameters and includes the provision of a rational framework for integrating ranges of epistemic uncertainties and aleatory variabilities in a comprehensive and transparent way. The developed seismic hazard model incorporates significant improvements over previous versions. It is based on updated and extended databases, it includes robust methods to evolve sets of models representing epistemic uncertainties, and a selection of the latest generation of ground motion prediction equations. The new earthquake model is presented here, which consists of a logic tree with 4040 end branches and essential innovations employed for a realistic approach. The output specifications were designed according to the user oriented needs as suggested by two review teams supervising the entire project. Seismic load parameters, for rock conditions of \(v_{S30}\) = 800 m/s, are calculated for three hazard levels (10, 5 and 2% probability of occurrence or exceedance within 50 years) and delivered in the form of uniform hazard spectra, within the spectral period range 0.02–3 s, and seismic hazard maps for peak ground acceleration, spectral response accelerations and for macroseismic intensities. Results are supplied as the mean, the median and the 84th percentile. A broad analysis of resulting uncertainties of calculated seismic load parameters is included. The stability of the hazard maps with respect to previous versions and the cross-border comparison is emphasized.     

砂岩储层AVO特征影响因素的不确定性研究

传统的地震AVO正演研究多采用参数固定的岩石物理模型,而实际地层属性参数在勘探范围内具有不确定性.本研究以目标地层岩芯样品的实验室测试数据为基础,通过样品孔隙度和干燥状态下纵、横波阻抗的高度线性关系对岩石物理模型进行了简化,并结合实验测量和测井解释建立了主要模型参数的概率密度函数.采用Monte-Carlo随机正演和G...     

Bayesian spectral density approach for modal updating using ambient data

The problem of identification of the modal parameters of a structural model using measured ambient response time histories is addressed. A Bayesian spectral density approach (BSDA) for modal updating is presented which uses the statistical properties of a spectral density estimator to obtain not only the optimal values of the updated modal parameters but also their associated uncertainties by calculating the posterior joint probability distribution of these parameters. Calculation of the uncertainties of the identified modal parameters is very important if one plans to proceed with the updating of a theoretical finite element model based on modal estimates. It is found that the updated PDF of the modal parameters can be well approximated by a Gaussian distribution centred at the optimal parameters at which the posterior PDF is maximized. Examples using simulated data are presented to illustrate the proposed method. Copyright © 2001 John Wiley & Sons, Ltd.     

Non‐parametric–parametric model for random uncertainties in non‐linear structural dynamics: application to earthquake engineering

This paper deals with the transient response of a non‐linear dynamical system with random uncertainties. The non‐parametric probabilistic model of random uncertainties recently published and extended to non‐linear dynamical system analysis is used in order to model random uncertainties related to the linear part of the finite element model. The non‐linearities are due to restoring forces whose parameters are uncertain and are modeled by the parametric approach. Jayne's maximum entropy principle with the constraints defined by the available information allows the probabilistic model of such random variables to be constructed. Therefore, a non‐parametric–parametric formulation is developed in order to model all the sources of uncertainties in such a non‐linear dynamical system. Finally, a numerical application for earthquake engineering analysis is proposed concerning a reactor cooling system under seismic loads. Copyright © 2003 John Wiley & Sons, Ltd.