建立地震预警、地震报警和烈度速报综合系统的思考

如何减少地震灾害所引起的人员伤亡、次生灾害以及快速判断灾情以落实全面的防御观,是我国自汶川地震以来非常关注的问题.在建设我国地震烈度速报和预警系统的背景下,我们提出尽可能减少投资以改变传统模式、建设不需要专门观测房的监测系统,提高烈度速报和预警系统的监测点密度,实现地震预警、报警和烈度速报综合系统,为全社会提供更好的防...     

日本地震预警系统发展历程

地震预警（EEW）或实时地震预警系统是指,几秒内检测到临近区域可能发生的强烈地震后,对本地提供预警信息的系统。地震预警的目标是,通过相应决策让人们能够在多种环境中保护自己,并减轻与地震相关的次生灾害。本文详细介绍了地震预警系统在日本的发展历程,指出预警信息已不再局限于向高级用户和公众用户进行发布,私人定制用户已成为预警信息发布的重要需求。未来地震预警技术的发展,特别是实时断层源成像识别技术,对改善预警系统并快速识别震源参数具有重要意义。     

地震预警定位方法研究

实时地震定位是地震预警系统中必须解决的关键问题之一.文中在借鉴已有实时地震定位方法的基础上并结合我国台网的实际情况,推导得到一套利用前三/四台P波、S波到时信息进行实时定位的算法.作者选取2000年至2008年问福建省地震监测台网记录到的68个3.0级以上地震对该算法进行验证.研究结果表明,采用文中方法的定位结果具有一...     

Evaluation of earthquake signal characteristics for early warning

This paper evaluates different characteristics for earthquake early warning.The scaling relationships between magnitude,epicenter distance and calculated parameters are derived from earthquake event data from USGS.The standard STA/LTA method is modified by adding two new parameters to eliminate the effects of the spike-type noise and small pulsetype noise ahead of the onset of the P-wave.After the detection of the P-wave,the algorithm extracts 12 kinds of parameters from the first 3 seconds of the P-wave.Then stepwise regression analysis of these parameters is performed to estimate the epicentral distance and magnitude.Six different parameters are selected to estimate the epicentral distance,and the median error for all 419 estimates is 16.5 km.Four parameters are optimally combined to estimate the magnitude,and the mean error for all events is 0.0 magnitude units,with a standard deviation of 0.5.Finally,based on the estimation results,additional work is proposed to improve the accuracy of the results.     

地震预警震级确定方法研究

地震预警技术是减轻地震灾害损失的有效手段之一．地震预警系统中,地震震级计算是最重要也是最困难的部分之一．利用日本KiK-net台网和四川汶川余震共142次地震事件的记录,分别采用tau;c和Pd方法统计得到了地震预警震级的计算公式,震级计算的方差分别为0.62和0.56个震级单位．为消除震级计算过程中出现的震级饱和现象,作者拓展了Pd方法,提出了一套对位移幅值连续追踪测定的算法．当时间窗长度为10 s时,采用该方法的震级计算方差仅为0.37个震级单位,充分满足地震预警系统的需求．同时,该方法也实现了信息的连续过渡,提高了对现有信息的利用率．最后,还对位移幅值Pd用于地震动峰值PGV的估计以及不同特征参数间的相容性等内容进行了讨论．      

地震预警系统与智能应急控制系统研究

基于实时地震(强震动)观测台网的地震预警和地震应急控制系统是近年来国际上日益引起人们重视的防震减灾手段，它不仅可以减轻地震造成的人员伤亡和降低重大工程次生灾害的发生，而且还可为震后紧急救援和抢修提供依据。对地震预警的基本思想以及地震预警和应急控制系统的国内外建设现状进行综述。     

Need of performance‐based earthquake engineering in Taiwan: a lesson from the Chichi earthquake

The objectives of seismic engineering are to design and build better and more economic earthquake‐resistant structures. Performance, which is measured as the amount of damage of a facility and the impact of damage to the society after an earthquake, is the main concern. Performance‐based earthquake engineering (PBEE) implies design, evaluation, and construction of engineered facilities whose performance under common and extreme earthquake ground motions responds to the diverse needs and objectives of the owners, users and society. Observations on the performance or damage of structures after strong earthquake ground motions have always served as an effective means to evaluate the current seismic regulations and guidelines and make further improvements afterwards. This paper presents some of the typical damage evidence after the Chichi earthquake occurred recently in Taiwan. Important issues in performance‐based earthquake engineering that need to be considered in future seismic regulations of Taiwan are addressed accordingly. Copyright © 2000 John Wiley & Sons, Ltd.     

Post‐earthquake bridge repair cost and repair time estimation methodology

While structural engineers have traditionally focused on individual components (bridges, for example) of transportation networks for design, retrofit, and analysis, it has become increasingly apparent that the economic costs to society after extreme earthquake events are caused at least as much from indirect costs as direct costs due to individual structures. This paper describes an improved methodology for developing probabilistic estimates of repair costs and repair times that can be used for evaluating the performance of new bridge design options and existing bridges in preparation for the next major earthquake. The proposed approach in this paper is an improvement on previous bridge loss modeling studies—it is based on the local linearization of the dependence between repair quantities and damage states so that the resulting model follows a linear relationship between damage states and repair points. The methodology uses the concept of performance groups (PGs) that account for damage and repair of individual bridge components and subassemblies. The method is validated using two simple examples that compare the proposed method to simulation and previous methods based on loss models using a power–law relationship between repair quantities and damage. In addition, an illustration of the method is provided for a complete study on the performance of a common five‐span overpass bridge structure in California. Intensity‐dependent repair cost ratios (RCRs) and repair times are calculated using the proposed approach, as well as plots that show the disaggregation of repair cost by repair quantity and by PG. This provides the decision maker with a higher fidelity of data when evaluating the contribution of different bridge components to the performance of the bridge system, where performance is evaluated in terms of repair costs and repair times rather than traditional engineering quantities such as displacements and stresses. Copyright © 2009 John Wiley & Sons, Ltd.     

地震预警信息可靠度研究

提出了一种地震预警信息可靠度检验方法. 针对地震预警系统对信息的高度时效性及准确性要求, 并结合其应用特点, 从地震动记录信噪比、 特征参数相容性、 特征参数协调性及地震预警定位结果可靠性等4个方面对地震预警信息的综合可靠度进行探讨, 并分别提出了相应的可靠度定量计算方法. 利用日本KiK-net台网记录的444个地震事件共4737条三分向加速度记录对上述4个指标参数及综合可靠度指标参数的验证结果表明, 采用本方法有助于提高地震预警信息发布的准确性和可靠性, 减少“漏报”及“误报”事件的发生.     

Accounting for directionality as a function of structural typology in performance‐based earthquake engineering design

For the seismic design of a structure, horizontal ground shaking is usually considered in two perpendicular directions, even though real horizontal ground motions are complex two‐dimensional phenomena that impose different demands at different orientations. While the issue of ground motion dependence on the orientation of the recording devices has been the focus of many significant developments during the last decade, the effects of directionality on the characteristics of the structure have received less attention. This work presents a proposal to calculate the probability of exceedance of elastic spectral displacements accounting for structural typology and illustrates its relevance by means of its application to two case‐study buildings. In order to ease its implementation in seismic design codes, a simplification is developed by means of a detailed statistical analysis of the results obtained using four sets of real hazard curves. The framework presented herein is considered to represent an important contribution to the field of performance‐based earthquake engineering, permitting improved treatment of directionality effects within seismic risk design and assessment. Copyright © 2016 John Wiley & Sons, Ltd.     

2022年1月8日青海门源6.9级地震机器学习地震预警震级估计与现地阈值报警的回溯验证

2022年1月8日1时45分青海省海北州门源县发生6.9级地震, 周边地区普遍有感, 并导致多条高铁线路临时停运. 本文利用这次地震获取的大量烈度计加速度记录, 基于正在进行系统研发的机器学习地震预警方法模块, 对地震预警震级估计与现地阈值报警进行了回溯验证. 结果表明: 在地震发生后3.1 s, 震级估计为6.5级, 且震级估计误差不受信噪比和震中距变化的影响, 随着首台触发后时间的增加, 震级估计逐渐接近实际震级. 对于现地地震动速度峰值PGV(Peak Ground Velocity)预测, 各个台站在P波到达后3 s时, 预测PGV与观测PGV呈现1:1线性关系, 随着P波到达后时间窗的增加, 预测PGV逐步接近观测PGV, 且PGV预测误差不受信噪比和震中距变化的影响. 现地台站仪器烈度阈值设置为Ⅵ度时, 报警成功、误报、漏报的百分比分别为99.53%、0%、0.47%, 平均预警时间为19.62 s, 且地震烈度Ⅵ度区内没有发生误报和漏报; 现地台站仪器烈度阈值设置为Ⅶ度时, 报警成功、误报、漏报的百分比分别为99.77%、0%、0.23%, 平均预警时间为9.69 s, 且地震烈度Ⅶ度区内没有发生误报和漏报. 此次回溯验证结果表明: 机器学习方法在这次地震中可以得到鲁棒的震级估计和现地阈值报警结果, 并为该方法的在线测试以及中国地震预警系统升级提供可行性依据; 其次, 在这次地震事件中, 烈度计可为预警提供额外的作用, 这也为烈度计在未来地震预警的研究和应用中提供了更多的可能性.

     

基于卷积神经网络的地震预警震级持续估算方法研究

为提高地震预警震级快速持续估算结果的准确性,本文构建了基于多种地震动特征参数的卷积神经网络震级估算CNN-M模型.该模型基于日本KiK-net强震动观测记录,利用其P波触发后3～ 10s时间窗内的幅值参数、周期参数、烈度参数、信噪比参数共11种地震波特征参数以及震中距参数作为输入.本文所建立的CNN-M模型随着地震发生...     

地震预警系统在提高中国台湾地区地震速报时效性中的作用

利用地震预警系统对中国台湾地区地震进行速报,与传统地震告警软件对比后发现,预警系统能够在较短时间内得出地震三要素并告警,可为地震速报人员争取较长速报用时。总结了地震速报过程中需要注意的若干细节问题。     

核电站强震动观测与地震预警述评

简要介绍强震动观测和地震预警技术及其在核电站工程中的应用情况.基于有关导则相关要求的介绍,对核电站强震观测系统的一般要求进行说明,分别以Beznau核电站和我国某核电站为例,介绍了强震仪测点的布置情况.以立陶宛Ignalina核电站为例,对地震预警技术在核电站中的应用情况做了分析和探讨.最后,提出了今后核电站地震观测和地震预警中值得关注的有关问题.     

地震预警连续定位方法研究

本文首先总结了地震预警系统中采用的一些实时定位方法,随后结合我国地震监测台网实际运行情况,提出了一套从单个台站触发开始逐渐过渡到利用前四台触发信息的完整地震预警连续定位方法.利用福建省地震监测台网记录的68个M3.0级以上地震观测记录,对本文方法的验证结果表明,对于网内地震,采用本文方法的单台定位结果误差均小于为50 km,双台定位结果误差均小于35 km,三台定位结果误差约为15 km,四台定位结果误差约为6 km;网外地震的三台、四台定位结果误差均小于30 km.推导了采用本文三、四台预警定位方法的误差公式.利用福建地区现有及"十一五"完成后的地震观测台网分别计算得到了定位误差分布图.根据误差分析结果即可对定位结果的可靠性预先做出判断,有利于提高地震预警系统运行的可靠性.     

地震预警PGV-Pd关系参数的距离分段特征

地震预警系统需要在破坏性的地震波到来前快速估算地震参数和地震动参数,以对可能出现的地震灾害进行预测,对重要工程、人员密集区域发布警报信息.以Pd估测PGV的方法是地震预警研究涉及的一种重要问题,该方法利用初至P波触发后前几秒的峰值位移（Pd）对最终地震动峰值速度（PGV）进行估算,以满足预警的需要.本文对2016年在日本发生的熊本地震及其前震、余震的震中距100 km以内、矩震级大于4级、井下基岩PGA>5 cm·s^-2和地表PGA>20 cm·s^-2的Kik-net强地震动记录进行处理分析,用于研究以Pd估测PGV的方法.将获得的强地震动数据按震中距从0~100 km平均划分为5个区段,在记录时间3~10 s范围内将Pd的计算取8个时间窗,分别对每个震中距区段、每一个Pd的时间窗下的PGV-Pd数据进行线性拟合,最终提出了一套应对不同震中距对位移幅值连续追踪测定PGV的算法.对每一个震中距区段的研究表明,震中距会对PGV-Pd关系产生影响.对5次地震进行验证分析,认为基于基岩记录估测基岩PGV的准确度高于基于地表记录估测地表PGV的准确度;对震中距进行分段的PGV估测方法准确度高于不考虑震中距因子的估测方法.最后拓展了将井下基岩Pd估测井下基岩PGV这种原地地震预警方法,使其能够为异地P波预警方法服务.

     

Post‐earthquake functionality of highway overpass bridges

Bridges are crucial to the transportation network in a region struck by an earthquake. Collapse of a bridge determines if a road is passable. Ability of a bridge to carry traffic load after an earthquake determines the weight and speed of vehicles that can cross it. Extent of system and component structural damage in bridges determines the cost and time required for repair. Today, post‐earthquake bridge evaluation is qualitative rather than quantitative. The research presented in this paper aims to provide a quantitative engineering basis for quick and reliable evaluation of the ability of a typical highway overpass bridge to function after an earthquake. The Pacific Earthquake Engineering Research (PEER) Center's probabilistic performance‐based evaluation approach provides the framework for post‐earthquake bridge evaluation. An analytical study was performed that linked engineering demand parameters to earthquake intensity measures. The PEER structural performance database and reliability analysis tools were then used to link demand parameters to damage measures. Finally, decision variables were developed to describe three limit states, repair cost, traffic function, and collapse, in terms of induced damage. This paper presents the analytical models used to evaluate post‐earthquake bridge function, decision variables and their correlation to the considered limit states, and fragility curves that represent the probability of exceeding a bridge function limit state given an earthquake intensity. Copyright © 2005 John Wiley & Sons, Ltd.     

Closed‐form aftershock reliability of damage‐cumulating elastic‐perfectly‐plastic systems

Major earthquakes (i.e., mainshocks) typically trigger a sequence of lower magnitude events clustered both in time and space. Recent advances of seismic hazard analysis stochastically model aftershock occurrence (given the main event) as a nonhomogeneous Poisson process with rate that decays in time as a negative power law. Risk management in the post‐event emergency phase has to deal with this short‐term seismicity. In fact, because the structural systems of interest might have suffered some damage in the mainshock, possibly worsened by damaging aftershocks, the failure risk may be large until the intensity of the sequence reduces or the structure is repaired. At the state‐of‐the‐art, the quantitative assessment of aftershock risk is aimed at building tagging, that is, to regulate occupancy. The study, on the basis of age‐dependent stochastic processes, derived closed‐form approximations for the aftershock reliability of simple nonevolutionary elastic‐perfectly‐plastic damage‐cumulating systems, conditional on different information about the structure. Results show that, in the case hypotheses apply, the developed models may represent a basis for handy tools enabling risk‐informed tagging by stakeholders and decision makers. Copyright © 2013 John Wiley & Sons, Ltd.     

地震预警系统与智能应急控制系统研究

江西省地震烈度速报与预警工程是对江西省现有地震监测台网进行加密和升级后,形成的地震烈度速报与预警观测网络和紧急地震信息服务网络,向社会公众和政府部门及时提供紧急地震信息服务。本文介绍了江西省地震烈度速报与预警工程基本情况,重新对江西省地震监测能力进行了计算,并对地震预警能力进行了评估。