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1.
Earthquake early warning systems (EEWS) are considered to be an effective, pragmatic, and viable tool for seismic risk reduction in cities. While standard EEWS approaches focus on the real-time estimation of an earthquake’s location and magnitude, innovative developments in EEWS include the capacity for the rapid assessment of damage. Clearly, for all public authorities that are engaged in coordinating emergency activities during and soon after earthquakes, real-time information about the potential damage distribution within a city is invaluable. In this work, we present a first attempt to design an early warning and rapid response procedure for real-time risk assessment. In particular, the procedure uses typical real-time information (i.e., P-wave arrival times and early waveforms) derived from a regional seismic network for locating and evaluating the size of an earthquake, information which in turn is exploited for extracting a risk map representing the potential distribution of damage from a dataset of predicted scenarios compiled for the target city. A feasibility study of the procedure is presented for the city of Bishkek, the capital of Kyrgyzstan, which is surrounded by the Kyrgyz seismic network by mimicking the ground motion associated with two historical events that occurred close to Bishkek, namely the 1911 Kemin (M?=?8.2; ±0.2) and the 1885 Belovodsk (M?=?6.9; ±0.5) earthquakes. Various methodologies from previous studies were considered when planning the implementation of the early warning and rapid response procedure for real-time risk assessment: the Satriano et al. (Bull Seismol Soc Am 98(3):1482–1494, 2008) approach to real-time earthquake location; the Caprio et al. (Geophys Res Lett 38:L02301, 2011) approach for estimating moment magnitude in real time; the EXSIM method for ground motion simulation (Motazedian and Atkinson, Bull Seismol Soc Am 95:995–1010, 2005); the Sokolov (Earthquake Spectra 161: 679–694, 2002) approach for estimating intensity from Fourier amplitude spectra; and the Tyagunov et al. (Nat Hazard Earth Syst Sci 6:573–586, 2006) approach for risk computation. Innovatively, all these methods are jointly applied to assess in real time the seismic risk of a particular target site, namely the city of Bishkek. Finally, the site amplification and vulnerability datasets considered in the proposed methodology are taken from previous studies, i.e., Parolai et al. (Bull Seismol Soc Am, 2010) and Bindi et al. (Soil Dyn Earthq Eng, 2011), respectively. 相似文献
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Matteo Picozzi Claus Milkereit Kevin Fleming Eser Çakti Jochen Zschau 《Journal of Seismology》2011,15(4):557-578
A seismic antenna approach based on the generalized zero-lag cross-correlation method for rapid earthquake localization is
proposed. This method is intended to be applied primarily for early warning, whenever the epicentre-to-target distances guarantee
enough lead-time, rapid response purposes, and for those circumstances when a seismogenic area is not directly accessible
with seismic stations or/and a network of instruments is concentrated within the area to be warned. The procedure we propose
aims to provide useful information for magnitude determination and shake-maps generation. Indeed, it relies only on the first
P-wave triggered arrivals from seismic stations, and is designed to work in real-time for the localization of events occurring
outside of the network, that is, under conditions that might be detrimental to standard localization approaches. The procedure
can by summarized by a few preliminary pre-seismic and real-time co-seismic steps. In the pre-seismic time-frame, for the
cases where a large and dense network exists, waiting for all stations to trigger could dramatically reduce the available
lead-time for the warning. Therefore, in such cases, the network could profitably be divided into sub-arrays, while also taking
advantage of available earthquake recordings or simulated data sets. During the co-seismic time-frame, the main operations
are: (1) individual on-site triggering by the P-wave of the seismic stations (e.g. by a STA/LTA algorithm); (2) real-time
communication of key parameters (e.g. P-wave arrival time, and signal quality) to a main centre by SMS/WLAN; (3) setup of
a pseudo data set, composed by a Gaussian function centred at the P-time, and with a bell width that can be set up proportional
to the trigger signal-to-noise ratio (SNR); (4) calculation of a coherency map for the sub-array with triggered stations (preliminary
sub-array location); and (5) stacking of coherency maps from the different sub-arrays (final location). By the stack of coherency
maps estimated by the different sub-arrays in the last step of the procedure, the epicentral area’s location may be better
constrained. This innovative approach for rapid localization was applied to both synthetic data, and real observations of
two small earthquakes that occurred in the Marmara Sea, Turkey, which were recorded by the Istanbul Earthquake Rapid Response
System. 相似文献
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Earthquake early warning systems (EEWS) seem to have potential as tools for real‐time seismic risk management and mitigation. In fact, although the evacuation of buildings requires warning time not available in many urbanized areas threatened by seismic hazard, they may still be used for the real‐time protection of critical facilities using automatic systems in order to reduce the losses subsequent to a catastrophic event. This is possible due to the real‐time seismology, which consists of methods and procedures for the rapid estimation of earthquake features, as magnitude and location, based on measurements made on the first seconds of the P‐waves. An earthquake engineering application of earthquake early warning (EEW) may be intended as a system able to issue the alarm, if some recorded parameter exceeds a given threshold, to activate risk mitigation actions before the quake strikes at a site of interest. Feasibility analysis and design of such EEWS require the assessment of the expected loss reduction due to the security action and set of the alarm threshold. In this paper a procedure to carry out these tasks in the performance‐based earthquake engineering probabilistic framework is proposed. A merely illustrative example refers to a simple structure assumed to be a classroom. Structural damage and non‐structural collapses are considered; the security action is to shelter occupants below the desks. The cost due to a false alarm is assumed to be related to the interruption of didactic activities. Results show how the comparison of the expected losses, for the alarm‐issuance and non‐issuance cases, allows setting the alarm threshold on a quantitative and consistent basis, and how it may be a tool for the design of engineering applications of EEW. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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Vincenzo Convertito Iunio Iervolino Aldo Zollo Gaetano Manfredi 《Soil Dynamics and Earthquake Engineering》2008,28(6):492-505
The development and implementation of an earthquake early warning system (EEWS), both in regional or on-site configurations can help to mitigate the losses due to the occurrence of moderate-to-large earthquakes in densely populated and/or industrialized areas. The capability of an EEWS to provide real-time estimates of source parameters (location and magnitude) can be used to take some countermeasures during the earthquake occurrence and before the arriving of the most destructive waves at the site of interest. However, some critical issues are peculiar of EEWS and need further investigation: (1) the uncertainties on earthquake magnitude and location estimates based on the measurements of some observed quantities in the very early portion of the recorded signals; (2) the selection of the most appropriate parameter to be used to predict the ground motion amplitude both in near- and far-source ranges; (3) the use of the estimates provided by the EEWS for structural engineering and risk mitigation applications.In the present study, the issues above are discussed using the Campania–Lucania region (Southern Apennines) in Italy, as test-site area. In this region a prototype system for earthquake early warning, and more generally for seismic alert management, is under development. The system is based on a dense, wide dynamic accelerometric network deployed in the area where the moderate-to-large earthquake causative fault systems are located.The uncertainty analysis is performed through a real-time probabilistic seismic hazard analysis by using two different approaches. The first is the Bayesian approach that implicitly integrate both the time evolving estimate of earthquake parameters, the probability density functions and the variability of ground motion propagation providing the most complete information. The second is a classical point estimate approach which does not account for the probability density function of the magnitude and only uses the average of the estimates performed at each seismic station.Both the approaches are applied to two main towns located in the area of interest, Napoli and Avellino, for which a missed and false alarm analysis is presented by means of a scenario earthquake: an M 7.0 seismic event located at the centre of the seismic network.Concerning the ground motion prediction, attention is focused on the response spectra as the most appropriate function to characterize the ground motion for earthquake engineering applications of EEWS. 相似文献
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2021年5月22日2时4分青海省玛多县发生M7.4地震。四川地震预警台网成功地处理并产出了本次地震预警结果。本文针对四川地震预警系统产出的8次地震预警处理结果及预警减灾效能进行了分析。此次地震震中距四川地震预警网55km,首台触发后12.19s发布首次预警处理结果,前5次预警处理结果用时距离首台触发时间均小于35s。与正式地震目录对比,第1次预警处理结果震中位置偏差为17.1km,震级偏差为-1.8,盲区半径为121km。随着参与计算台站数量增多,震中位置偏差和震级偏差不断减小,盲区半径不断增大。由于地震破裂时间长和台站限幅等原因,8次预警震级均偏小。本次地震预警的有效获益区为震中距121～324km的环形区域,此区域内减灾效能显著。本次地震预警结果表明,四川地震预警系统在本次地震中预警产出效果较好,对于网外大地震预警有重要参考意义。 相似文献
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利用川西流动地震台阵、汶川地震震后应急台网记录到的P波到时资料,对2008年5月至2008年10月期间发生的汶川地震余震序列应用双差层析成像方法进行了地震震源和三维P波速度结构的联合反演.结果显示,联合反演获得的地震重定位结果与基于一维地壳参考模型的双差定位方法结果相近;研究区15 km以上速度结构与地表断裂分布密切相关,20 km以下深度呈现北东向和北西向交错结构.汶川地震破裂带南段龙门山断裂带之间上地壳呈现高速异常,速度结构的非均匀变化是控制余震分布和主震破裂传播的主要因素;联合反演结果给出了小鱼洞-理县方向存在隐伏断裂的速度结构证据,同时发现,破裂带北东段可能沿新发断裂扩展;结果确认了汶川地震起始段的高角度逆冲断裂特征,也确认了前山断裂和中央断裂在约20 km深度合并到脆韧转换带的特征. 相似文献
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Earthquake‐induced structural response output‐only identification by two different Operational Modal Analysis techniques 
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下载免费PDF全文 Output‐only system identification is developed here towards assessing current modal dynamic properties of buildings under seismic excitation. Earthquake‐induced structural response signals are adopted as input channels for two different Operational Modal Analysis (OMA) techniques, namely, a refined Frequency Domain Decomposition (rFDD) algorithm and an improved Data‐Driven Stochastic Subspace Identification (SSI‐DATA) procedure. Despite that short‐duration, non‐stationary, earthquake‐induced structural response signals shall not fulfil traditional OMA assumptions, these implementations are specifically formulated to operate with seismic responses and simultaneous heavy damping (in terms of identification challenge), for a consistent estimation of natural frequencies, mode shapes, and modal damping ratios. A linear ten‐storey frame structure under a set of ten selected earthquake base‐excitation instances is numerically simulated, by comparing the results from the two identification methods. According to this study, best up‐to‐date, reinterpreted OMA techniques may effectively be used to characterize the current dynamic behaviour of buildings, thus allowing for potential Structural Health Monitoring approaches in the Earthquake Engineering range. 相似文献
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Application of an earthquake early warning system and a real-time strong motion monitoring system in emergency response in a high-rise building 总被引：1，自引：0，他引：1
Tomohiro Kubo Yoshiaki Hisada Masahiro Murakami Fusako Kosuge Kohei Hamano 《Soil Dynamics and Earthquake Engineering》2011
We apply a combination of earthquake early warning system (EEWS) and real-time strong motion monitoring system (RSMS) to emergency response for a high-rise building; The Kogakuin University has a 29-story high-rise building in Shinjuku Ward, Tokyo. The proposed strategy is based on the Plan, Do, Check, Action (PDCA) Cycle to brush up the systems and the users: in the “Plan” stage, we apply EEWS and RSMS to the building, where EEWS predicts not only short-period strong ground motions but also long-period ground motions [1]. The system is built into a building announcement system, an emergency elevator control system, and an email message system, which quickly send emails to the emergency response team. Meanwhile, RSMS provides information on seismic intensities at each floor of the building via the web browser in real time using the existing network in the building. In addition, the building response and structural damage can be estimated based on this information. The network system is impervious to the earthquake damage, because the network cable has extra length, there is, however, possible that a network system does not work due to power outage. Thus, we develop the network system that has uninterruptible power-supply system (UPS) and apply it to EEWS and RSMS. The high-rise building has the emergency call units to the security control center in the building on every floor. The emergency call line, however, will be busy promptly, because it is able to use only one line. Therefore, we installed IP telephone which uses the network system on main floors. UPS will work about 30 min after a major earthquake, it is supposed to be enough time for gathering the damage information about the building during initial response. In the “Do” stage, we prepare emergency response instruction manuals and educate the faculty members and students to carry out promptly emergency response. In the “Check” stage, the validity of the proposed systems are verified by carrying out an earthquake drill in an actual high-rise building. The earthquake drill confirmed that our proposed approach is valid. In the final “Action” stage, we improve these systems and emergency response manual and educate people in the building how to use effectively these systems. 相似文献
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本文利用喜马拉雅二期科学探测台阵的678个地震台站及26个固定台站记录到的9,641个地震共约160000条远震P波走时数据,采用基于稀疏约束的多尺度层析成像方法,获得了鄂尔多斯西缘及邻区上地幔800 km深度范围内P波速度结构.结果显示,在东经104°附近阿拉善地块与鄂尔多斯盆地间存在岩石圈深度的构造边界,这表明阿拉善地块与鄂尔多斯可能分别从属于不同的大地构造单元.以北纬38°线为界,鄂尔多斯地块西缘在岩石圈范围内南北存在明显的速度差异,鄂尔多斯南部上地幔200~300 km深度范围显示为高速异常,而鄂尔多斯北部上地幔显示大面积的低速异常.这一现象表明,鄂尔多斯地块南北两部分经历了不同的构造演化过程.根据本文的结果可以进一步推断,由于青藏高原、阿拉善地块向东北方向推挤以及岩石圈的拆离引起的上地幔扰动导致了地幔上涌,上涌的热物质改造了鄂尔多斯西北缘地区的岩石圈,并使该区的岩石圈减薄.地幔上涌也可能是东经104°边界带和北纬38°构造带形成的深部动力学因素. 相似文献
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Pankaj M. Bhattacharya J. R. Kayal Saurabh Baruah S. S. Arefiev 《Pure and Applied Geophysics》2010,167(8-9):999-1012
We have imaged earthquake source zones beneath the northeast India region by seismic tomography, fractal dimension and b value mapping. 3D P-wave velocity (Vp) structure is imaged by the Local Earthquake Tomography (LET) method. High precision P-wave (3,494) and S-wave (3,064) travel times of 980 selected earthquakes, m d ≥ 2.5, are used. The events were recorded by 77 temporary/permanent seismic stations in the region during 1993–1999. By the LET method simultaneous inversion is made for precise location of the events as well as for 3D seismic imaging of the velocity structure. Fractal dimension and seismic b value has been estimated using the 980 LET relocated epicenters. A prominent northwest–southeast low Vp structure is imaged between the Shillong Plateau and Mikir hills; that reflects the Kopili fault. At the fault end, a high-Vp structure is imaged at a depth of 40 km; this is inferred to be the source zone for high seismic activity along this fault. A similar high Vp seismic source zone is imaged beneath the Shillong Plateau at 30 km depth. Both of the source zones have high fractal dimension, from 1.80 to 1.90, indicating that most of the earthquake associated fractures are approaching a 2D space. The spatial fractal dimension variation map has revealed the seismogenic structures and the crustal heterogeneities in the region. The seismic b value in northeast India is found to vary from 0.6 to 1.0. Higher b value contours are obtained along the Kopili fault (~1.0), and in the Shillong Plateau (~0.9) The correlation coefficient between the fractal dimension and b value is found to be 0.79, indicating that the correlation is positive and significant. To the south of Shillong Plateau, a low Vp structure is interpreted as thick (~20 km) sediments in the Bengal basin, with almost no seismic activity in the basin. 相似文献
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C. La Mura T. B. Yanovskaya F. Romanelli G. F. Panza 《Pure and Applied Geophysics》2011,168(1-2):201-216
It is an acquired result that, in order to enable realistic earthquake hazard assessment and reliable estimation of the ground motion response to an earthquake, three-dimensional velocity models have to be considered. In this paper we present a new analytical procedure for determining the seismic wavefield in a 3D anelastic model based on the combination of the ray theory with the modal summation method. The proposed procedure has been validated by considering the three-dimensional model of the Kanto basin (Japan) available in the literature. Three-dimensional simulations were performed for the 1990 Odawara earthquake. The results obtained were compared both with recorded signals and with simulations available in the literature for several stations located within the Kanto basin. Besides the advantage of being a useful tool for assessment of seismic hazard and seismic risk reduction, it is characterized by high efficiency, in fact, once the study region is identified and the 3D model is constructed, the computation, at each station, of the three components of the synthetic signal (displacement, velocity, and acceleration) takes less than 3?h on a 2?GHz CPU. 相似文献
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2014年9月晋冀蒙临时地震台网正式运行,为晋冀蒙交界地区的地震研究提供了丰富的资料。结合临时台与固定台记录的P波走时资料,采用双差层析成像方法对该区进行地震重定位和三维P波速度结构联合反演,分析该区3个典型盆地的速度扰动结果,结果表明,地震重定位残差显著降低,震源深度分布更加合理;P波速度浅层基本符合平原地区低速、山区高速的特点,深层则有相反表现,典型盆地P波速度在浅层较为复杂,高低速相间,深层表现为低速;研究时段内忻定盆地和延怀盆地地震活动密集,大同盆地地震活动较弱,低速体及边缘地震活动强度高于高速体及边缘。 相似文献
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在台网比较稀疏的情况下,台站走时标定是提高低震级事件定位、识别能力的重要手段．为了提高稀疏台网的定位精度,首先利用标定事件和IASPEI1991走时表以及中国大陆走时表,计算了初至P波和Lg波到AAK,MAKZ,NIL,TLG以及WMQ等5个台站的走时残差;接着,采用非平稳贝叶斯克里金方法和走时残差数据构造上述台站的走时校正曲面;最后,通过加入和不加入走时校正定位一系列位置准确的发生在新疆地区的地震事件评估克里金走时校正的有效性．结果表明,克里金走时校正能够较大地提高稀疏台网的定位精度,同时有效地缩小误差椭圆的面积． 相似文献
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The 50% and 90% P-wave detection thresholds of 3 Austrian, 2 Czech, 5 German, 1 Hungarian and 3 Slovak seismic stations have been determined for four intervals of epicentral distances by a direct method using the maximum-likelihood technique. The USGS-NEIC Earthquake Data Reports covering the period from January 1990 to November 1994 were used as the reference system. The seismic stations Kaperské Hory (KHC, Czech Republic) and Collmberg (CLL, Germany) are the stations with the best detection capabilities for all investigated intervals of epicentral distances. 相似文献
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本文在利用多台研究1999年11月29日和2000年1月12日发生在辽宁岫岩Ms5.4级和5.1级地震前拐角频率比随时间变化的基础上,对岫岩、营口、苏家屯、丹东、宽甸、北镇、新民单台记录的纵横波拐角频率比fcp/fcs做了比较详细的波谱分析。结果表明:在震中距小于200 km以内的不同方向的台站,记录到的地震波拐角频率比值在5.4级前和后均出现不同程度的异常显示,能够捕捉到一些带有短临性质的信息,不过,距震中较远的台站,地震波拐角频率比值在震前异常不如近台明显,表明不同距离的台站,记录的地震拐角频率比值存在着差异。 相似文献
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利用2008年10月5日新疆乌恰6.8级地震时新疆强震动观测台记录的S波资料和脉动观测资料,采用Nakamura方法计算了这些强震观测台的场地响应.结果表明:(1)地震记录前10 s的脉动场地响应明显大于测试脉动和地震记录S波的场地响应,是测试脉动和记录S波场地响应的3倍,而测试脉动场地响应和S波记录场地响应基本相符.... 相似文献