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1.
The first 7 years of the National Tsunami Hazard Mitigation Program (NTHMP) have had a significant positive impact on operations of the Richard H. Hagemeyer Pacific Tsunami Warning Center (PTWC). As a result of its seismic project, the amount and quality of real-time seismic data flowing into PTWC has increased dramatically, enabling more rapid, accurate, and detailed analyses of seismic events with tsunamigenic potential. Its tsunameter project is now providing real-time tsunameter data from seven strategic locations in the deep ocean to more accurately measure tsunami waves as they propagate from likely source regions toward shorelines at risk. These data have already been used operationally to help evaluate potential tsunami threats. A new type of tsunami run-up gauge has been deployed in Hawaii to more rapidly assess local tsunamis. Lastly, numerical modeling of tsunamis done with support from the NTHMP is beginning to provide tools for real-time tsunami forecasting that should reduce the incidence of unnecessary warnings and provide more accurate forecasts for destructive tsunamis. 相似文献
2.
The U.S. National Tsunami Hazard Mitigation Program (NTHMP) is a State/Federal partnership created to reduce tsunami hazards along U.S. coastlines. Established in 1996, NTHMP coordinates the efforts of five Pacific States: Alaska, California, Hawaii, Oregon, and Washington with the three Federal agencies responsible for tsunami hazard mitigation: the National Oceanic and Atmospheric Administration (NOAA), the Federal Emergency Management Agency (FEMA), and the U.S. Geological Survey (USGS). In the 7 years of the program it has, 1. established a tsunami forecasting capability for the two tsunami warning centers through the combined use of deep ocean tsunami data and numerical models; 2. upgraded the seismic network enabling the tsunami warning centers to locate and size earthquakes faster and more accurately; 3. produced 22 tsunami inundation maps covering 113 coastal communities with a population at risk of over a million people; 4. initiated a program to develop tsunami-resilient communities through awareness, education, warning dissemination, mitigation incentives, coastal planning, and construction guidelines; 5. conducted surveys that indicate a positive impact of the programs activities in raising tsunami awareness. A 17-member Steering Group consisting of representatives from the five Pacific States, NOAA, FEMA, USGS, and the National Science Foundation (NSF) guides NTHMP. The success of the program has been the result of a personal commitment by steering group members that has leveraged the total Federal funding by contributions from the States and Federal Agencies at a ratio of over six matching dollars to every NTHMP dollar. Twice yearly meetings of the steering group promote communication between scientists and emergency managers, and among the State and Federal agencies. From its initiation NTHMP has been based on the needs of coastal communities and emergency managers and has been results driven because of the cycle of year-to-year funding for the first 5 years. A major impact of the program occurred on 17 November 2003, when an Alaskan tsunami warning was canceled because real-time, deep ocean tsunami data indicated the tsunami would be non-damaging. Canceling this warning averted an evacuation in Hawaii, avoiding a loss in productivity valued at $68M. 相似文献
3.
David H. Oppenheimer Alex N. Bittenbinder Barbara M. Bogaert Raymond P. Buland Lynn D. Dietz Roger A. Hansen Stephen D. Malone Charles S. McCreery Thomas J. Sokolowski Paul M. Whitmore Craig S. Weaver 《Natural Hazards》2005,35(1):59-72
In 1997, the Federal Emergency Management Agency (FEMA), National Oceanic and Atmospheric Administration (NOAA), U.S. Geological Survey (USGS), and the five western States of Alaska, California, Hawaii, Oregon, and Washington joined in a partnership called the National Tsunami Hazard Mitigation Program (NTHMP) to enhance the quality and quantity of seismic data provided to the NOAA tsunami warning centers in Alaska and Hawaii. The NTHMP funded a seismic project that now provides the warning centers with real-time seismic data over dedicated communication links and the Internet from regional seismic networks monitoring earthquakes in the five western states, the U.S. National Seismic Network in Colorado, and from domestic and global seismic stations operated by other agencies. The goal of the project is to reduce the time needed to issue a tsunami warning by providing the warning centers with high-dynamic range, broadband waveforms in near real time. An additional goal is to reduce the likelihood of issuing false tsunami warnings by rapidly providing to the warning centers parametric information on earthquakes that could indicate their tsunamigenic potential, such as hypocenters, magnitudes, moment tensors, and shake distribution maps. New or upgraded field instrumentation was installed over a 5-year period at 53 seismic stations in the five western states. Data from these instruments has been integrated into the seismic network utilizing Earthworm software. This network has significantly reduced the time needed to respond to teleseismic and regional earthquakes. Notably, the West Coast/Alaska Tsunami Warning Center responded to the 28 February 2001 Mw 6.8 Nisqually earthquake beneath Olympia, Washington within 2 minutes compared to an average response time of over 10 minutes for the previous 18 years. 相似文献
4.
The National Tsunami Hazard Mitigation Program (NTHMP) Steering Committee consists of representatives from the National Oceanic and Atmospheric Administration (NOAA), the Federal Emergency Management Agency (FEMA), the U.S. Geological Survey (USGS), and the states of Alaska, California, Hawaii, Oregon, and Washington. The program addresses three major components: hazard assessment, warning guidance, and mitigation. The first two components, hazard assessment and warning guidance, are led by physical scientists who, using research and modeling methods, develop products that allow communities to identify their tsunami hazard areas and receive more accurate and timely warning information. The third component, mitigation, is led by the emergency managers who use their experience and networks to translate science and technology into user-friendly planning and education products. Mitigation activities focus on assisting federal, state, and local officials who must plan for and respond to disasters, and for the public that is deeply affected by the impacts of both the disaster and the pre-event planning efforts. The division between the three components softened as NTHMP scientists and emergency managers worked together to develop the best possible products for the users given the best available science, technology, and planning methods using available funds. 相似文献
5.
Real-Time Tsunami Forecasting: Challenges and Solutions 总被引：8，自引：0，他引：8
A new method for real-time tsunami forecasting will provide NOAAs Tsunami Warning Centers with forecast guidance tools during an actual tsunami event. PMEL has developed the methodology of combining real-time data from tsunameters with numerical model estimates to provide site- and event-specific forecasts for tsunamis in real time. An overview of the technique and testing of this methodology is presented. 相似文献
6.
Local Tsunami Warning in the Pacific Coastal United States 总被引：2，自引：1，他引：1
Coastal areas are warned of a tsunami by natural phenomena and man-made warning systems. Earthquake shaking and/or unusual water conditions, such as rapid changes in water level, are natural phenomena that warn coastal areas of a local tsunami that will arrive in minutes. Unusual water conditions are the natural warning for a distant tsunami. Man-made warning systems include sirens, telephones, weather radios, and the Emergency Alert System. Man-made warning systems are normally used for distant tsunamis, but can be used to reinforce the natural phenomena if the systems can survive earthquake shaking. The tsunami warning bulletins provided by the West Coast/Alaska and Pacific Tsunami Warning Centers and the flow of tsunami warning from warning centers to the locals are critical steps in the warning process. Public knowledge of natural phenomena coupled with robust, redundant, and widespread man-made warning systems will ensure that all residents and tourists in the inundation zone are warned in an effective and timely manner. 相似文献
7.
The National Tsunami Hazard Mitigation Program is a multi-faceted approach that encompasses tsunami identification, alert and warning systems and a comprehensive approach to tsunami risk reduction. This paper describes efforts to promote land use planning and development practices that reduce tsunami risk by local elected government and administrative officials. Seven Principles of Tsunami Risk Reduction are presented that range from risk assessment to site planning criteria.Regional Administrator, California Governors Office of Emergency Services and Manager, California Integrated Seismic Network, Earthquake and Tsunami Program 相似文献
8.
This paper describes an investigation of the subfault distribution along the Japan–Kuril–Kamchatka subduction zone for the
implementation of a far-field tsunami forecast algorithm. Analyses of seismic data from 1900 to 2000 define the subduction
zone, which in turn is divided into 222 subfaults based on the fault characteristics. For unit slip of the subfaults, a linear
long-wave model generates a database of mareograms at water-level stations along the subduction zone and at warning points
in the North Pacific. When a tsunami occurs, an inverse algorithm determines the slip distribution from near-source water-level
records and predicts the waveforms at the warning points using the pre-computed mareograms. A jackknife resampling scheme
uses combinations of input water-level records to provide a series of waveform predictions for the computation of the confidence-interval
bounds. The inverse algorithm is applied to hindcast two major tsunamis generated from the Japan–Kuril–Kamchatka source and
the computed tsunami heights show good agreement with recorded water-level data. 相似文献
9.
海啸作为五大海洋自然灾害之一,严重威胁着人类生命财产安全。近些年来,国内外学者对地震海啸进行了大量研究,主要针对海啸的生成、传播、爬高和淹没的数值模拟,以及古海啸沉积物进行研究,但是对于海啸地震震源机制的研究还比较欠缺,尤其是缺乏对震级小于6.5的海啸地震的研究。针对我国的地震海啸研究现状,强调震级小于6.5地震引发海啸的问题不容忽视。本文归纳整理了全球766次地震海啸,利用三角图分类基本法则对海啸地震震源机制解进行分类,并对其中341个发生在1976年后的海啸地震进行震源机制解分析,对其中633次海啸浪高进行统计学方法分析研究。本文认为逆冲型、正断型、走滑型和奇异型机制地震均能引发海啸,逆冲型地震引发的海啸占比最大,震级小于6.5级地震引发的海啸的浪高也有高达10 m的情况,也能产生巨大破坏性。逆冲型、正断型、奇异型地震可直接引起海底地形垂向变化,进而引发海啸,而走滑型地震引发海啸则可能有两种原因,一种是走滑型地震并非纯走滑型而是带有正断或逆冲分量从而引发海啸,另外一种是走滑型地震引发海底滑坡导致海底地形变化进而产生海啸。从海啸地震震源深度分析,能产生海啸的地震震源深度97%以上都是浅源地震,主要集中在30 km深度以内,但是也有中深源地震海啸。本文综合海啸地震的震源特点、我国地理位置以及以往海啸发生的情况,认为未来我国沿海地区威胁性的地震海啸主要集中在马尼拉海沟和台湾海峡区域,在今后海啸预警方面需要格外重视这些区域,通过建立完善海啸预警系统来减少损失。 相似文献
10.
Patricia A. Lockridge 《Natural Hazards》1990,3(4):403-412
While earthquakes generate about 90% of all tsunamis, volcanic activity, landslides, explosions, and other nonseismic phenomena can also result in tsunamis. There have been 53 000 reported deaths as a result of tsunamis generated by landslides and volcanoes. No death tolls are available for many events, but reports indicate that villages, islands, and even entire civilizations have disappeared. Some of the highest tsunami wave heights ever observed were produced by landslides. In the National Geophysical Data Center world-wide tsunami database, there are nearly 200 tsunami events in which nonseismic phenomena played a major role. In this paper, we briefly discuss a variety of nonseismic phenomena that can result in tsunamis. We discuss the magnitude of the disasters that have resulted from such events, and we discuss the potential for reducing such disasters by education and warning systems. 相似文献
11.
柯长青 《中国地质灾害与防治学报》2006,17(4):91-96
2004年12月26日印度尼西亚苏门答腊岛西北近海发生ML9级强烈地震。地震的强度是100a来全球非常罕见的。地震引起了巨大海啸,浪高近10m,波及到东南亚、南亚和东非地区10多个国家,造成近30万人遇难。地震使印度尼西亚、泰国的部分岛屿发生了地形变化。海啸在受灾国留下了大片的盐碱地。苏门答腊板块边缘的一个长距离破裂带通过长时间积累,蓄积了巨大能量。这些能量在2004-12-26集中释放出来。导致了这次地震海啸的发生。地震海啸灾害本身规模巨大,发生异常突然,再加上受灾地区人员密集,缺乏海啸灾害逃生的知识和经验。印度洋沿岸国家没有海啸预警系统,是造成这次灾害巨大伤亡的原因。中国从台湾-海南岛一线的海区,存在地震海啸的可能性。因此应不断完善海啸预警系统,提高沿海地区建设工程的防灾抗灾标准,加强防波堤建设以及采取恢复红树林等生物工程措施,预防潜在的海啸灾害。 相似文献
12.
Tsunami hazard assessment begins with a compilation of past events that have affected a specific location. Given the inherent limitations of historical archives, the geological record has the potential to provide an independent dataset useful for establishing a richer, chronologically deeper time series of past events. Recent geological studies of tsunami are helping to improve our understanding of the nature and character of tsunami sediments. Wherever possible, geologists should be working to improve the research ‘tool kit’ available to identify past tsunami events. Marine foraminifera (single celled heterotrophic protists) have often been reported as present within tsunami-deposited sediments but in reality, little information about environmental conditions, and by analogy, the tsunami that deposited them, has been reported even though foraminifera have an enormous capacity to provide meaningful palaeo-environmental data. Here, we review what foraminifera are, describe their basic form and significance, summarise where they have been reported in tsunami sediments and identify what can be learnt from them. We review the gaps in our understanding and make recommendations to assist researchers who examine foraminiferal assemblages in order to enhance their use within tsunami geology. 相似文献
13.
Far-Field Tsunami Potential and a Real-Time Forecast System for the Pacific Using the Inversion Method 总被引：1，自引：0，他引：1
Estimating tsunami potential is anessential part of mitigating tsunami disasters. Weproposed a new method to estimate the far-fieldtsunami potential by assuming faultmodels on the Pacific Rim. We find thata tsunami that generates in the areas wherethere is no tsunami in the history can damagethe Japanese coast. This shows that it isimportant to estimate tsunami potential byassuming fault models other than the pastearthquake data.Another important activity to mitigate tsunamidisasters is to provide appropriatewarnings to coastal communities when dangerfrom a tsunami is imminent. We applied anew inversion method using wavelet transformto a part of the real-time tsunami forecastsystem for the Pacific. Because this inversionmethod does not require fault location, it ispossible to analyze a tsunami in real timewithout all seismic information. In order tocheck the usability of the system, anumerical simulation was executed assuming anearthquake at sea off Taiwan. The correlationcoefficient for the estimated initialwaveform to the assumed one was calculatedto be 0.78. It takes 90 min to capturetime-series waveform data from tsunamigauges and 5 sec to estimate the 2-D initialwaveform using the inversion method. After that,it takes 2 minutes to forecast thetsunami heights at the Japanese coast. Since thesum of these times is less than the 105minutes transit time of the tsunami fromTaiwan to Japan, it is possible to give a warningto the residents before the tsunami attacksthe Japanese coast. Comparing the tsunamiheights forecasted by this system with thosecalculated by the fault model, the averageerror was 0.39 m. The average error ofthe arrival time was 0.007 min. 相似文献
14.
The exhaustive review of a long number of historical documents, books, reports,scientific and press reports, instrumental recordings, previous catalogues andpersonal field observations, concluded with the production of a completely newtsunami catalogue for the Corinth Gulf, Central Greece, which is arranged in theformat adopted by the GITEC group for the new European Tsunami Catalogue.The catalogue is presented in three sections: the Quick-Look Table, the Quick-LookAccounts File and the References File. An Appendix explains why some particularsea disturbances were not included in the new catalogue although they were consideredas tsunami events by previous researchers. Past history clearly shows that most tsunamis in the Corinth Gulf are produced by strong (Ms 5.5) offshore and near shore earthquakes. However, seismic or aseismic sliding of coastal and submarine sediments is a significant factor in tsunamigenesis. Calculations based on the random model indicate that the probability for at least one tsunami occurrence of intensity TI 2 TI 3 and TI 4 within 50 years equals 0.851, 0.747 and 0.606, respectively. From the intensity–frequency relationship the mean return period of tsunami intensity TI 2, TI 3 and TI 4 equals to 16, 40 and 103 years. The tsunami geographicaldistribution, however, is non-random with a clear trend for the tsunamigenesis todecrease drastically from west to east within the Corinth Gulf. In fact, the probabilityfor a strong earthquake to cause a tsunami of TI 3 in the Corinth Gulf consideredas an entity is 0.35, while in the western part of the Gulf it goes up to 0.55. Therefore, the rapid and accurate determination of the earthquake focal parameters is of great importance in an algorithm of a real-time tsunami warning system in the Corinth Gulf. 相似文献
15.
The Hauraki Gulf is a semi-enclosed sea next to the largest population centre in New Zealand, the Auckland metropolitan region. The potential tsunami hazard is of concern to regional and local planners around the Hauraki Gulf. The Hauraki Gulf has recorded 11 tsunamis and one meteorological tsunami (rissaga) since 1840.The historical tsunami data are relatively sparse, particularly for the largest events in 1868 and 1883. Moreover, local sources may produce damaging tsunamis but none has occurred during recorded history. Therefore numerical modelling of potential tsunami events provides a powerful tool to obtain data for planning purposes. Three main scenarios have been identified for numerical modelling:1. A teletsunami event from an earthquake off the West Coast of South America. Historically this region has produced the largest teletsunamis in the Hauraki Gulf.2. A tsunami generated by a local earthquake along the Kerepehi Fault. This fault bisects the Gulf, has been active during the last century at the southern inland end, and is overlain by a considerable thickness of soft sediment that may amplify the seismic waves.3. A tsunami generated by a volcanic eruption within the Auckland Volcanic Field. This field has involved a series of mainly monogenetic basaltic eruptions over the last 140,000 years. Many of these eruptions have involved phreatomagmatic eruptions around the coastal margins, or within the shallow waters close to Auckland. 相似文献
16.
Longwave Measurements for the Coast of British Columbia and Improvements to the Tsunami Warning Capability 总被引：1，自引：0，他引：1
A few years ago the Canadian Hydrographic Service initiated a major upgrade toall tide gauges and tsunami stations on the coast of British Columbia (B.C.). Thisprogram was undertaken to address shortcomings of the earlier digital systems andwas driven by concerns about emergency response continuity in the year 2000. By1999, thirteen tide gauge stations had been installed and were operational. Three ofthese stations (Tofino, Winter Harbour, and Langara) were selected for use as tsunamiwarning stations. Several years of continuous, high quality data have now been collectedat these stations and used for analysis of long waves in the tsunami frequency band.Careful examination of these data revealed two weak tsunamis recorded by severalB.C. stations: a distant tsunami of June 23, 2001 generated by the Peru Earthquake(Mw = 8.4), and a local tsunami of October 12, 2001 induced by the Queen Charlotte Earthquake (Mw = 6.3$). Spectral characteristics of these two tsunamis are compared with the spectral characteristics of long waves generated by a strong storm (October, 2000) and of ordinary background oscillations. The topographic admittance functions (frequency responses) constructed for all stations showed that most of them (in particular, Winter Harbour, Tofino, Bamfield, Port Hardy, and Victoria) have strong resonance at periods from 2.5 to 20 min, indicating that these locations are vulnerable to relatively high-frequency tsunamis. The Winter Harbour station also has two strong resonant peaks with periods of 30 and 47 min and with amplification factors of about 7. The estimated source functions show very clear differences between long waves associated with the seismic source (typical periods 10–30 min) and those generated by a storm, which typically have shorter periods and strong energy pumping from high-frequencies due to non-linear interaction of wind waves. 相似文献
17.
18.
N. Shuto 《Natural Hazards》1991,4(2-3):171-191
Hindcasting of a tsunami by numerical simulations is a process of lengthy and complicated deductions, knowing only the final results such as run-up heights and tide records, both of which are possibly biased due to an insufficient number of records and due to hydraulic and mechanical limitation of tide gauges. There are many sources of error. The initial profile, determined with seismic data, can even be different from the actual tsunami profile. The numerical scheme introduces errors. Nonlinearity near and on land requires an appropriate selection of equations. Taking these facts into account, it should be noted that numerical simulations produce satisfactory information for practical use, because the final error is usually within 15% as far as the maximum run-up height is concerned.The state-of-the-art of tsunami numerical simulations is critically summarized from generation to run-up. Problems in the near future are also stated. Fruitful application of computer graphics is suggested. 相似文献
19.
I. N. Tikhonov N. F. Vasilenko D. E. Zolotukhin T. N. Ivelskaya A. A. Poplavsky A. S. Prytkov A. I. Spirin 《Russian Journal of Pacific Geology》2008,2(1):1-14
The earthquakes and tsunami on November 15, 2006 and January 13, 2007, near Simushir Island are described. Long-term and short-term precursors of the phenomena are discussed. A joint analysis of the seismological and geodetic data provided reliable interpretation of the source mechanisms of the earthquakes. The actions of the tsunami warning personnel are analyzed. Extensive experimental data on the tsunami occurrence at different sites of the Pacific Ocean are presented. The tsunami of November 15, 2006, was numerically modeled using coseismic vertical displacements of the ocean bottom calculated from GPS data. The observed and calculated data on the maximal tsunami run up are compared. 相似文献
20.
A Human Damage Prediction Method for Tsunami Disasters Incorporating Evacuation Activities 总被引：1，自引：0，他引：1
This study presents a tsunami human damage prediction method employing numerical calculation and GIS (Geographical Information System) for Usa town, Tosa City, Shikoku Island, Japan. Sometime near the end of the first half of the twenty-first century, a huge earthquake is predicted to occur along the Nankai trough and costal areas facing the Pacific ocean of Shikoku Island. Much damage due to the resultant tsunamis will be caused, therefore, it is necessary to predict the extent of human damage for every town in high-risk areas.The number of tsunami victims was estimated by population in areas of maximum inundation. The number of deaths as a result of tsunami was estimated by a method which employed accumulated death toll of every area in terms of time and space, taking into account consideration of time necessary to begin to seek refuge after an earthquake, tsunami inundation depth on land, flow velocity and evacuation speed. As a result of this study a rapid decrease in death toll by early evacuation was shown quantitatively for the first time.Thus, with the method presented here, it is possible to estimate the extent of tsunami human damage on coastal regions, and may be useful as a tsunami human damage countermeasure. 相似文献