Expected loss‐based alarm threshold set for earthquake early warning systems     

Iunio Iervolino  Massimiliano Giorgio  Gaetano Manfredi 《地震工程与结构动力学》2007,36(9):1151-1168

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   

"数字地球"与实时地震学     

许力生 《国际地震动态》2001,(8):32-37

“数字地球”是对真实地球及其相关现象的统一性的数字化重现和认识，是信息化的地球，是地球的虚拟对照体。“数字地球”的科学体系由基础研究、技术支撑和科学工程三部分组成。现代地震学同样需要基础研究、支撑技术和科学工程，其中，最后一个体系即相当于实时地震学。实时地震学调基础研究和现代技术的结合，强调地震学研究成果的转化和对社会与公众的服务，是地震学发展的“最高境界”。实时地震学需要基础研究和现代技术，更需要建立地震速报系统、地震趋势分析系统、灾害评估系统和地震救灾系统这样的系统工程。  相似文献   

Scattering behaviour at Merapi volcano (Java) revealed from an active seismic experiment     

Ulrich Wegler  Birger&#;G. Lühr 《Geophysical Journal International》2001,145(3):579-592

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Is Iceland underlain by a plume in the lower mantle? Seismology and helium isotopes     

G. R. Foulger  D. G. Pearson 《Geophysical Journal International》2001,145(3):F1-F5

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The level of deterrence provided by data from the SPITS seismometer array to possible violations of the Comprehensive Test Ban in the Novaya Zemlya region   总被引：1，自引：0，他引：1  

David Bowers  Peter D. Marshall  Alan Douglas 《Geophysical Journal International》2001,146(2):425-438

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Wavefront healing: a banana–doughnut perspective     

S.&#;H. Hung  F. A. Dahlen  Guust Nolet 《Geophysical Journal International》2001,146(2):289-312

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Crustal and upper mantle seismic structure and lithospheric flexure along the Society Island hotspot chain     

Ingo Grevemeyer  Wilfried Weigel  Stefan Schüssler  Felix Avedik 《Geophysical Journal International》2001,147(1):123-140

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The geomorphology of planetary calderas   总被引：1，自引：0，他引：1  

Peter J. Mouginis-Mark  Scott K. Rowland 《Geomorphology》2001,37(3-4)

Satellite-derived observations of the geomorphology of calderas on Earth, Mars and Venus can be used to learn more about shield volcanoes. Examples of terrestrial basaltic volcanoes from the Galapagos Islands, Hawaii, and the Comoro Islands show how these volcanoes contrast with examples found on Mars and Venus. Caldera structure, degree of infilling, and the location of vents on the flanks are used to interpret each volcano's recent history. The geometry of the caldera floor can be used to infer some of the characteristics of the magma storage system, and the orientation of the deep magma conduits. The formation of benches within the caldera and the effects of the caldera on the distribution of flank eruptions are considered, and it is evident that most calderas on the planets are/were dynamic features. Presently, deep calderas, with evidence of overflowing lavas and ponded lavas high in the caldera wall, show that these calderas were once shallow. Similarly, shallow calderas filled with ponded lavas are evidence that they were once deeper. It is probably a mistake, therefore, to place great significance on caldera depth with regard to the position, shape, or size of subsurface plumbing.  相似文献   

Formation and failure of volcanic debris dams in the Chakachatna River valley associated with eruptions of the Spurr volcanic complex, Alaska   总被引：1，自引：0，他引：1  

Christopher F. Waythomas 《Geomorphology》2001,39(3-4)

The formation of lahars and a debris avalanche during Holocene eruptions of the Spurr volcanic complex in south-central Alaska have led to the development of volcanic debris dams in the Chakachatna River valley. Debris dams composed of lahar and debris-avalanche deposits formed at least five times in the last 8000–10,000 years and most recently during eruptions of Crater Peak vent in 1953 and 1992. Water impounded by a large debris avalanche of early Holocene (?) age may have destabilized an upstream glacier-dammed lake causing a catastrophic flood on the Chakachatna River. A large alluvial fan just downstream of the debris-avalanche deposit is strewn with boulders and blocks and is probably the deposit generated by this flood. Application of a physically based dam-break model yields estimates of peak discharge (Q_p) attained during failure of the debris-avalanche dam in the range 10⁴<Q_p<10⁶ m³ s⁻¹ for plausible breach erosion rates of 10–100 m h⁻¹. Smaller, short-lived, lahar dams that formed during historical eruptions in 1953, and 1992, impounded smaller lakes in the upper Chakachatna River valley and peak flows attained during failure of these volcanic debris dams were in the range 10³<Q_p<10⁴ m³ s⁻¹ for plausible breach erosion rates.Volcanic debris dams have formed at other volcanoes in the Cook Inlet region, Aleutian arc, and Wrangell Mountains but apparently did not fail rapidly or result in large or catastrophic outflows. Steep valley topography and frequent eruptions at volcanoes in this region make for significant hazards associated with the formation and failure of volcanic debris dams.  相似文献   

长白山天池火山密码破译势在必行     

金东淳  李范熙  崔钟燮 《地震地磁观测与研究》1996,(4)

长白山天池火山是中新世以来多次喷发并造成严重灾害的火山。通过十几年的火山地质及火山地震监测研究认为长白山天池火山近期不会马上喷发，但它是一座具有潜在喷发危险性的活动火山，并提出建立长白山火山观测站的重要意义，讨论了天地火山密码的破译需要调动各方面有利因素和有利条件。  相似文献