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使用云南区域台网记录的地震目录资料,采用破裂时间法模拟前兆地震序列能量加速释放过程,系统研究了能量加速释放模型参数估计方法及强震位置搜索技术,详细推导了预测模型基本公式,对小江断裂带上发生的19次主震事件进行了模拟,结果表明:强震前能量加速现象是一种普遍现象,主震前,与主震相差2.5个震级单位的前兆序列出现能量加速释放所占的比例为80%;由前兆序列模拟得到的预测时间和震级与实际值很接近,主震震级预测精度约为±0.5级,预测主震发生时间误差约为±0.5年;搜索半径和搜索时间与主震震级成线性正相关关系;采用主震位置搜索技术,对小江断裂带未来中期6~7级强震可能危险区进行了预测。 相似文献
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对某些类型的主震事件, 进行中短期预测也许是可能的. 利用Varnes, Bufe和Varnes提出的破裂时间法模拟前兆地震能量加速释放模型,通过实际观测资料与理论公式的拟合, 可以建立主地震事件的中短期预测技术, 用以确定表示主震的地点、时间和震级大小. 本文使用的是云南区域台网的地震目录资料,覆盖的时间段为1965~2002年. 统计分析表明,在此37年时间内,等于或大于2.5级地震资料是相当完整的. 本文对云南地区的30次主震事件进行了模拟,其中25次主震事件由前兆序列模拟得到的预测时间和震级与实际值相当接近,主震震级预测精度约0.57个震级单位,假定已知前兆序列中最后一次事件,则预测主震发生时间误差约0.64年.对另外的5次主震事件,由于没有足够的前兆事件来充分确定前兆能量加速曲线或是存在对能量加速释放曲线的干扰事件,而不能进行破裂时间法模拟.本文的研究结果还表明,由于云南是破坏性地震和中小地震活跃的地区,因此,主地震与前兆事件最佳搜索半径不存在明显的线性关系.主震矩与系数k,m之间存在强烈的相关性,利用主震地震矩与系数的关系和限制指数m的取值范围,可进一步缩小预测时间和预测震级的最佳拟合区范围,提高了模拟主震事件的预测精度. 本文采用破裂时间法对30次主震事件进行拟合,80%以上获得了较好的结果. 显示出该方法在预测已知主震事件序列的能力方面大有希望,因此,利用前兆事件对未来主震事件进行中短期预测的前景是令人鼓舞的. 相似文献
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根据由南加州地震目录回顾性地震建模及已发表的对新马德里震带的估算结果,改进型破裂时间法可以作为一种中期地震预测技术用来确定未来主震的地点并预测其大小和时间。提出假设并对先前主震的建模表明本方法预测的离震震级精度达到了约±0.5个震级单位。假设已有兆序列中最后的事件,则破裂时间误差约是±1.1年。当不知识序列中最后的事件时,预测震级保持桢,但随着时间的推移,往序列中追加事件时,预测时间将需要更新。本 相似文献
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短期地震概率(STEP)预测模型将大森-宇津余震衰减关系和古登堡~里克特频度-震级关系应用到地震丛集。这个模型主要用来预测余震活动,而依赖于时间不变的背景模型预测大多数主震。另一方面,长期地震预测模型EEPAS(根据尺度每个地震都有前兆)利用前兆尺度增加现象及相关的预测标度关系,取决于震级的大小可提前数月、数年或数十年预测主震。这两种模型均显现出比地震活动性不随时间变化的模型可提供更多的信息。通过将这两种模型混合在一起,我们期望形成包含更多信息的短期预测模型。本优化混合模型利用了加利福尼亚州1984~2004年间改进的国家地震系统目录,是一种预测M≥5.0级地震的凸线性组合,其中EEPAS预测量为0.42,STEP预测量为0.58。这种混合模型与每一种单独模型相比,平均概率增益大于2。数种不同的混合模型将提交到南加州地震中心的地震预测能力研究合作实验室(CSEP)检测中心,用以确定该结果是否由这些模型对未来地震的实时检测产生出。 相似文献
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水库地震主震发生时间的预测 总被引:1,自引:2,他引:1
水利工程对水库地震的抗震设防要求事先对水为地震进行预测。预测内容包括蓄水后诱发地震的危险性(可能性、)最大震级、最大震的地占紧及不库地震对场址地震动参数的影响。除主震时间的预测外,本文第一作者都曾提出过初步的预测方法。本文认为,水库地震前震波速比异常、非线性灰色模型以及前震系列回归等方法,是预测主震时间的有前途的方法。 相似文献
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天兴洲公铁两用斜拉桥主梁纵向列车制动振动反应分析 总被引:1,自引:0,他引:1
本文对天兴洲公铁两用斜拉桥主梁纵向列车制动的振动反应进行了研究。天兴洲大桥是目前在建的世界上跨度最大的公铁两用斜拉桥,由于具有四线铁路,其主梁在列车制动及行车移动荷载作用下会沿纵向产生大幅振动,因此对其列车制动及行车移动荷载反应进行研究尤为必要。文中,首先根据车辆动力学的原理建立了列车制动动力学模型,获得了列车制动力纵向荷载及在制动过程中列车行走所产生的竖向荷载,并建立制动力传递有限元模型,应用有限元分析软件来获取钢轨上制动力及列车行走时引起的桥梁结构节点上的作用力时程。最后对天兴洲公铁两用斜拉桥主梁纵向列车制动及行车移动荷载的振动反应进行了仿真分析,发现了其主梁纵向列车制动反应具有位移大且速度极小的特点。 相似文献
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PRE-ASSESSMENT OF EARTHQUAKE-INDUCED LOSSES BASED ON FIELD SURVEY AND KILOMETER GRID DATASET: A CASE STUDY FROM DEHONG DAI-JINGPO AUTONOMOUS PREFECTURE
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The pre-assessment of earthquake damage based on field surveys and grid dataset in 1km resolution is very helpful for emergency preparedness and mitigation of earthquake disaster losses.In this paper,we briefly introduced the contents,principles,methods and the results of software assessment as well as the revised results after field surveys.In addition,the emergency supplies and manpower requirements after the outbreak of earthquake are discussed.The assessment contents include the earthquake affected area and population,the amount of casualties,injuries,economic losses,and the number of population to be resettled.Scenario earthquake is set with an interval of 50 kilometers along the major faults and the losses induced by earthquake are outputted by the software.After that,the software outputs are revised based on field surveys.In addition,according to the earthquake cases happening between 2008 and 2015,the growth curve model used to estimate the demand of rescue supplies and teams is also proposed in this study.Based on this model and the software named earthquake emergency disaster rapid assessment and dynamic visualized software (NIE Gao-zhong,2014),and with the help of the statistical data such as population density and socio-economic situations,earthquake losses are pre-assessed by taking Dehong Dai-Jingpo Autonomous Prefecture as an example.The comparison shows that the actual losses are nearly the same as the software outputs.However,due to the ignorance of the casualties caused by geological disasters,the revised casualties are more than the software output.Not only the study area discussed in this paper,the earthquake loss assessment method can also be used to other regions in China. 相似文献
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从杂散电流腐蚀的数学模型、监测手段、防护措施和可展望的问题等方面,对交流电引起的杂散电流腐蚀进行系统评述。首先,介绍杂散电流腐蚀的机理及数据模型,并从不同行业学者所选取的模型及软件入手,介绍杂散电流腐蚀的模型建立的相关类型;其次,对目前杂散电流监测的主要方法及其自动监测系统的发展进行阐述;最后,介绍基于杂散电流腐蚀防护原则建立的防护体系及其相应特点,并对杂散电流腐蚀的监测中具有可行性发展的技术进行探讨。 相似文献
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将列车移动荷载简化为多个移动轮轴荷载,基于列车-轨道-路基解析模型推求的列车运行时不同时刻、不同位置时作用于路基的振动荷载时程,采用多点输入方式实现列车荷载的移动施加方式,建立路(地)基-场地体系三维有限元动力分析模型,基于Abaqus软件的并行计算集群平台,对轨道交通振动荷载下路(地)基-场地体系的动力反应进行数值模拟,研究了列车荷载作用线正下方地基中的动应力特征及土单元应力状态变化,分析了列车轮轴荷载移动过程中不同深度处土单元的应力路径和主应力轴的旋转。 相似文献
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It is proposed that the Straightforward Inversion Scheme (SIS) developed by the authors for 1D inversion of resistivity sounding and magneto-telluric sounding data can also be used in similar fashion for time-domain induced polarization sounding data. The necessary formulations based on dynamic dipole theory are presented. It is shown that by using induced polarization potential, measured at the instant when steady state current is switched off, an equation can be developed for apparent ‘chargeability–resistivity’ which is similar to the one for apparent resistivity. The two data sets of apparent resistivity and apparent chargeability–resistivity can be inverted in a combined manner, using SIS for a common uniform thickness layer earth model to estimate the respective subsurface distributions of resistivity and chargeability–resistivity. The quotient of the two profiles will give the sought after chargeability profile. A brief outline of SIS is provided for completeness. Three theoretical models are included to confirm the efficacy of SIS software by inverting only the synthetic resistivity sounding data. Then one synthetic data set based on a geological model and three field data sets (combination of resistivity and IP soundings) from diverse geological and geographical regions are included as validation of the proposal. It is hoped that the proposed scheme would complement the resistivity interpretation with special reference to shaly sand formations. 相似文献
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E. A. Spiridonov 《Seismic Instruments》2016,52(1):60-69
A comparative analysis of predicted values of delta factors and phase shifts of eight major tidal waves obtained using a newly developed domestic tidal prediction software ATLANTIDA3.1_2014, their observed values, and values calculated using the PREDICT software from the ETERNA3.4 package, averaging over nine oceanic tidal models, is carried out. According to various criteria, the results returned by our software proved to be on average closer to the observations on 14 superconducting gravimeters of the GGP network than the results calculated by the PREDICT software. It is shown that this result is obtained both by the use of a more modern oceanic tidal model (FES2012) and a new model of the variation of amplitude delta factors with latitude (Spiridonov, 2014a). 相似文献
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Lateral spreads of liquefied granular soil masses have caused severe damages to many engineered structures. Accordingly, many empirical procedures have been developed from field-direct observations and from multiple regression analyses carried out on the database gathered from many case histories. The intricacy and nonlinearity of the underlying phenomena makes the above approaches somewhat unreliable for estimating liquefaction-induced lateral spreads. The database has inconsistencies and contradictions because of inevitable subjective interpretations and neural network approaches have been proposed for dealing with these.To overcome these difficulties in this paper a hybrid system named neurofuzzy, which profits from fuzzy and neural paradigms, is advanced. The resulting model called NEFLAS (NEuroFuzzy estimation of liquefaction induced LAteral Spread) is shown to yield a much improved forecasting than both multiple regression and neural network procedures. The corresponding software can be obtained from the first author. 相似文献
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Shaking table test and numerical simulation of an RC frame‐core tube structure for earthquake‐induced collapse
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The reinforced concrete frame‐core tube structure is a common form of high‐rise building; however, certain vertical components of these structures are prone to be damaged by earthquakes, debris flow, or other accidents, leaving no time for repair or retrofit. This study is motivated by a practical problem—that is, the seismic vulnerability and collapse resistant capability under future earthquakes when a vertical member has failed. A reduced scale model (1:15 scale) of a typical reinforced concrete frame‐core tube with a corner column removed from the first floor is designed, fabricated, and tested. The corner column is replaced by a jack, and the failure behavior is simulated by manually unloading the jack. The model is then excited by a variety of seismic ground motions on the shaking table. Experimental results concerning the seismic responses and actual process of collapse are presented herein. Finally, the earthquake‐induced collapse process is simulated numerically using the software program ANSYS/LS‐DYNA. Validation and calibration of the model are carried out by comparison with the experimental results. Furthermore, based on both experimental investigations and numerical simulations, the collapse mechanism is discussed, and some suggestions on collapse design are put forward. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献