震源机制与海啸警报的关系

第三篇概述了震源机制与海啸警报的关系,指出:地震海啸同逆断层或正断层有关,而和走滑断层无关;为提高海啸警报的准确程度,必须在海啸警报系统中增加震源机制的判据。     

基于网络的加利福尼亚地震预警算法设计:ElarmS-2

加利福尼亚综合地震台网(CISN)正在为加利福尼亚州开发一种地震预警(EEW)示范系统。在加利福尼亚综合地震台网震动警报(ShakeAlert)项目中,正在检验3种算法,其中之一是基于台网的地震警报系统(ElarmS)的地震预警系统。在过去的3年中,ElarmS算法经历了大量重新评定和解决技术与方法的若干挑战。在新的生产级产品,即ElarmS第2版(简称ElarmS-2或E2)中,对算法的改进扩大到适用当前地震台网的布局,改进了硬件和软件的性能,提高了预警处理速度和警报的准确性。E2设计为模块化的代码,由改进关联器的新事件监测模块组成,可以更迅速地与少数触发关联匹配,同时也增加了几个新的警报过滤检查,从而帮助最大限度地减少虚报。本文概述了这个新的在线实时系统的方法,总结了其性能。从2012年10月2日到2013年2月15日的在线操作性能来看,平均而言,在所有加利福尼亚发生的地震事件中,ElarmS系统在初至P波到达后8.68±3.73s发布预警。这一时间在台站仪器密集地区减少了2s。震级和发震时刻的标准差为0.4级和1.2s,定位误差中值为3.8km。在加利福尼亚发生的29次地震(MANSS3.5)中,E2成功检测到26次,发布了两次虚报。E2现正传送警报给震动警报系统,由震动警报系统发布给测试用户。     

一种比地震波更快的新的警报系统

日本科学技术厅国立防灾科学技术中心提出一种新的警报系统的初步设想,它能在大地震发生时迅速测知,并能以比地震波还快的速度发出警报。这个新警报系统以作了预报部署的东海地震为假设条件,用专用线路将设置在骏河湾周围的地震仪群与首都圈连接在一起。再用电子计算机依次处理地震仪的数据,并输出与地震大小相应的信号。据计算,这种警报可在东海地震的地震波到达首都圈的20～30秒以前传到,在这段时间内可以采取防灾措施。     

一警报系统可向太平洋国家发布海啸警报

《美国地球物理联合会汇刊》1976年12月57卷4期852页刊登了一篇题为《海啸警报系统》的报道,全文译载如下: 一个警报系统通过广泛的通讯网侦测强力的高速海啸波,并向太平洋国家发出可能即将来临的自然灾害的警报。该通讯网于1948年由美国海岸与大地测量局建立,并已从1973年     

城市地震警报系统

经验和专家的分析告诉人们:即使在大地震前20秒钟发出警报,也可以大大减少人口伤亡。 本文讨论的地震警报系统,充分利用了电信号的传播速度比破坏性地震波(主要是横波和面波)快得多的特点,当90公里以外发生大地震时,可以在20秒前发出紧急警报。在1976年唐山地震时,假如天津市已建立了这种系统,可在大震前24秒发出警报;而北京市,则可在大震前28秒发出警报。     

减轻地震灾害

1989年10月旧金山地区地震后最令人可怕的景象是由煤气管道引燃而后在整个街区肆虐的大火。要是警报系统能在地震袭击一城市之前一二分钟响起警报,就能减轻这类灾害。警报可安装在诸如公用事业公司等关键场所,以便预先把煤气总管道关闭。美国全国大概有五六位科学家正在研制这种实时地震警报系统。这些系统依据的原理是:地震波要比无线电波传播得慢。通过卫星传送,这些系统能把重要设施与测量地面运动的仪器联接起来。在麻省理工学院,由地球、大气和行星科学系教授托克索茨(M.N.Toks(?)z)领导的小     

基于Java的桥梁强震动实时监测及警报系统开发与应用

本文使用Java语言,在测震台网《数据采集与常规处理》区域版(JOPENS)的基础上结合Socket、多线程等技术,开发出基于Client/Server(C/S)模式的桥梁强震动实时监测及警报系统,系统包括配置模块、数据采集模块、数据存储模块、监测模块、数据浏览模块、警报模块和数据分析模块,可跨平台安装。该系统已在多座大桥上稳定运行,可将其推广到其他重大工程结构的强震动监测及事件警报。     

墨西哥城采用新型地震预报系统

据路透社墨西哥城1993年8月1日电,一种新型电子警报系统已在墨西哥城投入使用,该城的居民将在大地震发生前1分钟得到警报。据认为,这种计算机化的无线电系统是世界上独一无二的。官员们说,在测到里氏6.0级以上地震来临时,该系统就会自动向该城的电台和电视台发出报警信号。     

地质学家们试图建立苏联地震警报系统

地震学家们正期待着苏联政府批准建立一个全国性的警报系统,以减少象去年12月袭击了亚美尼亚那样的地震所造成的破坏。苏联科学院地球物理研究所的地震预报研究项目负责人索博列夫(Gennady Sobolev)说:“我们知道如何建立一个预报、警报系统。”但是,他在会见政府日报——苏维埃俄罗斯报记者时说:“由于我们没有足够的仪器设备进行充分的地震监测,因此,我们的短期预测网很不完善。”索博列夫估计,在易震区建立监测台网需要花费3亿卢布(3亿英镑)。苏联有1/4以上的地区处于高地震危险之中。索博列夫说,受影响的地区主要在远东和     

苏联建立海啸警报系统

据塔斯社1984年4月23日在海参崴报导,苏联为了预告其易震的远东地区即将来临的海啸,正在建立一早期的警报系统。该报导简单介绍了有关该警报系统的设计情况。据称,该系统以最新技术为基础,并能保证可靠的自动工作。苏联任何一年记录到的     

An Integrated Multi-Level Early Warning Method for Rainfall-Induced Shallow Landslides

Rainfall-induced landslides have occurred frequently in Southwestern China since the Wenchuan earthquake,resulting in massive loss of people''s life and property. Fortunately,landslide early-warning is one of the most important tools for landslide hazard prevention and mitigation. However, the accumulation of historical data of the landslides induced by rainfall is limited in many remote mountain areas and the stability of the slope is easily affected by human engineering activities and environmental changes, leading to difficulties to accurately realize early warning of landslide hazards by statistical methods. The proposed warning method is divided into rainfall warning component and deformation warning component because the deformation induced by rainfall has the characteristic of hysteretic nature. Rainfall, tilted angle and crack width are chosen as monitoring indexes. Rainfall grade level that contains rainfall intensity and duration information is graded according to the variation of the safety factor calculated by 3-D finite difference numerical simulation method, and then is applied using the strength reduction method and unascertained information theory to obtain the deformation grade level of several monitored points. Finally, based on the system reliability theory, we establish a comprehensive landslide warning level method that provides four early warning levels to reflect the safety factor reductions during and post rainfall events. The application of this method at a landslide site yield generally satisfactory results and provide a new method for performing multi-index and multi-level landslide early warnings.     

雷电预警系统在区域台站中的应用

雷电是台站仪器设备主要的安全隐患。雷电预警是指在雷电发生前约几分至数十分钟内及时发出预警信息,实现台站电源控制的自动切换,达到保护台站仪器设备免遭雷击损失的目的。雷电预警监控系统软件,是基于对雷电预警装置电场数据的实时监控,通过引入区域雷达回波强度动态分布图作为辅助判断,构成有效范围的雷电预警监控网,达到为区域台站雷电预警服务的目的。     

Methodology to set trigger levels in an urban drainage flood warning system – an application to Jhonghe,Taiwan

A wireless water-level monitoring system for an urban drainage flood warning is developed, and stations equipped with pressure sensors are installed to monitor water levels. The water levels for flood warning are investigated. Two stages of warning water level for “larger” conduits are set based on the rate of rising water levels. In a similar way, only one stage of the warning water level is set for “smaller” conduits. The average rates of rising water levels for different scenarios are estimated using the US EPA Storm Water Management Model (SWMM). When evaluating the impact of flooding, the outflows from manholes simulated by the SWMM are used as sources for a two-dimensional overland flow simulation. The integrated system is successfully executed in Jhonghe, New Taipei City, Taiwan, which has experienced urban drainage floods. Therefore, this system can provide urban drainage flood warnings to the authorities to take disaster reduction measures.     

Evaluating flash-flood warnings at ungauged locations using post-event surveys: a case study with the AIGA warning system

Abstract

This article presents a comparison between real-time discharges calculated by a flash-flood warning system and post-event flood peak estimates. The studied event occurred on 15 and 16 June 2010 at the Argens catchment located in the south of France. Real-time flood warnings were provided by the AIGA (Adaptation d’Information Géographique pour l’Alerte en Crue) warning system, which is based on a simple distributed hydrological model run at a 1-km² resolution using radar rainfall information. The timing of the warnings (updated every 15 min) was compared to the observed flood impacts. Furthermore, “consolidated” flood peaks estimated by an intensive post-event survey were used to evaluate the AIGA-estimated peak discharges. The results indicated that the AIGA warnings clearly identified the most affected areas. However, the effective lead-time of the event detection was short, especially for fast-response catchments, because the current method does not take into account any rainfall forecast. The flood peak analysis showed a relatively good correspondence between AIGA- and field-estimated peak values, although some differences were due to the rainfall underestimation by the radar and rainfall–runoff model limitations.

Editor Z.W. Kundzewicz; Guest editor R.J. Moore

Citation Javelle, P., Demargne, J., Defrance, D., Pansu, J. and Arnaud, P., 2014. Evaluating flash-flood warnings at ungauged locations using post-event surveys: a case study with the AIGA warning system. Hydrological Sciences Journal, 59 (7), 1390–1402. http://dx.doi.org/10.1080/02626667.2014.923970     

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。     

Review of the 2018 Palu Tsunami:Disaster Behavior and Reflections on Disaster Management

The 2018 Palu M_W7.5 earthquake and tsunami attracted geophysicists'' attention for its strike slip focal mechanism and magnitude. We inspected the details of this disaster and discussed its particularity and possible causations. The submarine landslide and special terrain conditions could have contributed to the unusual size of the tsunami. The early warning system and the post disaster response is also reviewed. Efficient social warnings and broadcast systems along with good maintenance is essential. We also found that enhancing publics scientific literacy is the most important way to reduce disaster damage and casualties. Moreover, social conditions and rebuilding difficulties post tsunami are related as reference resources for future disaster management strategies.     

Tsunamigenic Earthquakes: Past and Present Milestones

We review a number of events which, taken individually, have significantly affected our understanding of the generation of tsunamis by earthquake sources and our efforts at mitigating their hazards, notably through the development of warning algorithms. Starting with the 1700 Cascadia earthquake, we examine how significant tsunamis have changed our views in fields as diverse as seismotectonics, the diversity of earthquake cycles, the development of warning algorithms, the response of communities at risk to warnings, and their education, the latter being either formal or rooted in ancestral heritage. We discuss in detail lessons from the 2004 Sumatra disasters and review the performance of warning centers and the response of affected populations during the nine significant tsunamis which have taken place since 2004.     

基于人工边坡稳定性的降雨型滑坡预警预报模型设计与应用

由削坡建房遗留的人工边坡存在大量滑坡隐患问题,在降雨引发土质边坡自身动力变化分析条件下,以稳定性评价建模为基础,提出降雨型滑坡动力学预警预报模型.文中以广东省梅州市花岗岩地区为例,使用GIS技术构建了1727个预警分析单元,并进行关键地质环境因子赋值及与气象站点数据关联;按坡高、坡度等参数,分别构建16个边坡失稳动力学...     

中国地震预警延迟时间算法及其对预警盲区的影响研究

通过分析预警系统的预警步骤来探讨影响获得预警时间的因素,并与瑞士地震台网预警延迟各步骤进行对比,得出中国地震预警系统仪器延迟时间为7.6s。提出地震波到台站所需时间的算法,较震中假设在台站中间的传统算法更为准确,在此算法下采用双台法和四台法计算接收地震波所需时间,得到中国地震预警延迟时间。讨论双台法和四台法在不同震源深度和台站密度下对预警盲区大小的影响,在台间距小于20km时,2种方法预警盲区差异不大。通过理论计算得出,在台站到达一定密度时,预警系统仪器延迟时间缩短比台站加密对预警盲区的缩小更有效。     

Progress of the earthquake early warning system in Fujian, China

In this article, we systematically introduce the latest progress of the earthquake early warning (EEW) system in Fujian, China. We focus on the following key technologies and methods: continuous earthquake location and its error evaluation; magnitude estimation; reliability judgment of EEW system information; use of double-parameter principle in EEW system information release threshold; real-time estimation of seismic intensity and available time for target areas; seismic-monitoring network and data sharing platform; EEW system information release and receiving platform; software test platform; and test results statistical analysis. Based on strong ground motion data received in the mainshock of the Wenchuan earthquake, the EEW system developed by the above algorithm is simulated online, and the results show that the system can reduce earthquake hazards effectively. In addition, we analyzed four earthquake cases with magnitude greater than 5.5 processed by our EEW system since the online-testing that was started one year ago, and results indicate that our system can effectively reduce earthquake hazards and have high practical significance.