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1.
国际海啸预警系统(ITWS)   总被引:5,自引:2,他引:5  
介绍了国际海啸预警系统的构成、地震与海啸信息的检测、海啸预警信息的发布,并介绍了太平洋海啸预警中心和阿拉斯加海啸预警中心。  相似文献   

2.
海南省南海地震监测和海啸预警服务   总被引:2,自引:1,他引:2  
2004年底发生在印度洋的地震海啸造成的巨大灾难引起了人们广泛的关注。根据海南岛有仪器记录到地震海啸的事实,从构造角度讨论了海南岛未来遭受地震海啸袭击的可能性,强调了建立海南省南海地震监测和海啸预警系统的必要性和重要性,并提出了预警系统建设的初步设想。  相似文献   

3.
海啸灾害及其预警系统   总被引:13,自引:0,他引:13  
地震海啸是最严重的自然灾害之一。2004年底印度洋大海啸更是震撼了全世界。本文对海啸的定义、性质、特征,历史上和近代的中国和世界的严重海啸灾害作了简单介绍。指出建立和完善海啸预警系统,可以在一旦海啸发生后,争取几十分钟甚至几小时时间,提前发出海啸警报信息,这就能极大地减轻海啸灾害。本文简单地介绍了海啸预警系统的主要内容。  相似文献   

4.
基于数值预报技术的日本新一代海啸预警系统   总被引:7,自引:2,他引:7  
日本是世界上地震海啸发生最频繁的国家之一。从1941年开始,日本气象厅就建立了自己的海啸预警系统。自1993年又一次遭受海啸灾害后,这些经历促使日本气象厅(JMA)开始研制基于数值预报技术的新一代海啸预警系统。该海啸预警系统包括地震监测网、基于数据库技术的快速数值预报以及基于卫星通讯的海啸预警产品快速分发系统这三部分。  相似文献   

5.
广东省地震海啸危险分析与监测预警系统构想   总被引:1,自引:0,他引:1  
杨马陵 《华南地震》2005,25(4):25-33
对广东省地震海啸的潜在危险进行了分析,认为广东省可能面临的海啸威胁主要来自南海东部。一旦发生地震海啸,将出现重大的灾害,并对广东省的社会和经济产生巨大的影响。提出了建立广东省地震海啸监测预警系统的初步构想。  相似文献   

6.
日本拥有全世界最密集的地震监测网络、最大的海啸防波堤、最广泛的地震预警系统。相比其他任何国家,日本国民在如何应对地震和海啸方面受过更严格的训练。  相似文献   

7.
海上丝绸之路深海地质灾害类型众多.主要分析了海底滑坡、三浅地质灾害和地震海啸这三种类型的地质灾害.传统多波束测深、三维地震勘探、深海钻探、声呐成像系统、海底地理信息系统是识别海底滑坡最有效手段.然而,准确解释和量化滑坡参数对于确定滑坡群的机制需要物理实验模拟和数值模拟;对于"三浅"地质灾害,地球物理技术是最有效的钻前预测方法,但在超压的定量预测方面还存在一些不足,识别准确度不高,因而,需要发展海底原位监测技术,提高"三浅"地质灾害的预测精度.南海海啸最主要的威胁来自其东部边缘的马尼拉俯冲带,而非印度洋.我国国家海洋环境预报中心已开发应对南海及其附近区域的潜在海啸威胁的定量海啸预警系统.但是,海上丝绸之路环俯冲带产生的地震海啸,影响甚广,亟待建立完善的预警系统.  相似文献   

8.
中国古籍中的地震海啸记录   总被引:15,自引:0,他引:15  
王锋  刘昌森  章振铨 《中国地震》2005,21(3):437-443
2004年12月26日的印度洋地震海啸波及10国,造成20余万人死亡和失踪、50万人受伤、100万人流离失所的浩劫,引发了人们对海洋地震灾害的关注。建立海啸预警系统的呼声也日趋强烈。我国海岸线长达32000km,我国的经济重心又相对集中在沿海地区,产业发达,人烟稠密,人们自然会对海啸表示相当的关注。本文在查阅大量地震史料的基础上,发现我国也有地震海啸发生,但除台湾外,其他地区并不严重,概率较低。为防患于未然,对我国自身的地震预警系统也应适当予以关注。  相似文献   

9.
基于强震台网的我国沿海海啸走时预警   总被引:4,自引:1,他引:4  
经济快速发展的中国沿海地区,面临着潜在海啸袭击危险。海啸传播走时分析是海啸预警系统的重要组成部分。本文基于强震台网提供的地震要素,从理论上讨论海啸预警时间计算方法。在球坐标系下,建立了远洋海啸传播模型,采用差分技术,实现远洋海啸传播数值模拟,首次针对我国主要城市进行了海啸走时计算,分析了我国沿海走时特点,指出了未来发生在太平洋的远洋海啸对我国的长江三角洲会有较大影响。本文计算海啸走时方法可以为我国建设的新一代基于数值海啸预警系统提供技术支持。  相似文献   

10.
葡萄牙破坏性地震和海啸预警系统(DETWS)   总被引:3,自引:0,他引:3  
本文介绍了葡萄牙破坏性地震和海啸预警系统(Destructive Earthquakes and Tsunami Warning System)的构成、地震与海啸信息的检测、海啸预警信息的发布。  相似文献   

11.
Tsunami Sediment Characteristics at the Thai Andaman Coast   总被引:1,自引:0,他引:1  
This paper describes and summarizes the 2004 Indian Ocean tsunami sediment characteristics at the Thai Andaman coast. Field investigations have been made approximately 3 years after the 2004 Indian Ocean tsunami event. Seven transects have been examined at five locations. Sediment samples have been collected for grain-size analyses by wet-sieve method. Tsunami sediments are compared to three deposits from coastal sub-environments. The mean grain-size and standard deviation of deposits show that shoreface deposits are fine to very fine sand, poorly to moderately well sorted; swash zone deposits are coarse to fine sand, poorly to well sorted; berm/dune deposits are medium to fine sand, poorly to well sorted; and tsunami deposits are coarse to very fine sand, poorly to moderately well sorted. A plot of deposit mean grain-size versus sorting indicates that tsunami deposits are composed of shoreface deposits, swash zone deposits and berm/dune deposits as well. The tsunami sediment is a gray sand layer deposited with an erosional base on a pre-existing soil (rooted soil). The thickness of the tsunami sediment layer is variable. The best location for observation of the recent tsunami sediment is at about 50–200 m inland from the coastline. In most cases, the sediment layer is normally graded. In some cases, the sediment contains rip-up clasts of muddy soils and/or organic matter. The vertical variation of tsunami sediment texture shows that the mean grain-size is fining upward and landward. Break points of slope in a plot of standard deviation versus depth mark a break in turbulence associated with a transition to a lower or higher Reynolds number runup. This can be used to evaluate tsunami sediment main layer and tsunami sediment sub layers. The skewness of tsunami sediment indicates a grain size distribution with prominent finer-grain or coarse-grain particles. The kurtosis of tsunami sediment indicates grain-size distributions which are flat to peak distribution (or multi-modal to uni-modal distribution) upward. Generally, the major origins of tsunami sediment are swash zone and berm/dune zone sands where coarse to medium sands are the significant material at these locations. The minor origin of tsunami sediment is the shoreface where the significant materials are fine to very fine sands. However, for a coastal area where the shoreface slope is mild, the major origin of tsunami sediment is the shoreface. The interpretation of runup number from tsunami sediment characteristics gets three runups for the 2004 Indian Ocean tsunami at the Thai Andaman coast. It corresponds to field observations from local eyewitnesses. The 1st runup transported and deposited more coarse particles than the following runups. Overall, the pattern of onshore tsunami sediment transportation indicates erosion at swash zone and berm/dune zone, followed by dynamic equilibrium at an area behind the berm/dune zone and after that deposition at inland zone until the limit of sediment inundation. The total deposition is a major pattern in onshore tsunami sediment transportation at the deposition zone which the sediment must find in the direction of transport.  相似文献   

12.
以马尼拉海沟的北断层发生MW8.0地震在南海引发海啸为假想的模拟情景, 利用E-FAST法定量分析了COMCOT海啸数值模型输出(最大海啸波高)对震级, 震源深度, 震中位置和断层走向、 倾角、 滑动角等震源参数的敏感性, 以及各震源参数间的交互效应对最大海啸波高的影响. 结果表明, 观测点B1( 20.1°N, 119.4°E)、 B2(18.4°N, 118.1°E)和B3(13.5°N, 117.6°E)的最大海啸波高都对震级十分敏感, 对震中位置、 断层走向和倾角较为敏感. 敏感的震源参数在影响上述3个观测点的最大海啸波高时, 与其它震源参数产生了较强的交互效应. 但是对于不同的观测点, 各震源参数的重要度排序则存在一定的差异. 该分析结果有助于更好地认识海啸波高与潜在海啸源参数之间的关系.   相似文献   

13.
We examined the geochemical characteristics and temporal changes of deposits associated with the 2011 Tohoku‐oki tsunami. Stable carbon isotope ratios, biomarkers, and water‐leachable ions were measured in a sandy tsunami deposit and associated soils sampled at Hasunuma, Kujukuri coastal plain, Japan, in 2011 and 2014. At this site, the 2011 tsunami formed a 10–30 cm ‐thick layer of very fine to medium sand. The tsunami deposit was organic‐poor, and no samples contained any detectable biomarkers of either terrigenous or marine origin. In the underlying soil, we identified hydrocarbons and sterols derived from terrestrial plants, but detected no biomarkers of marine origin. In the samples collected in 2011, concentrations of tsunami‐derived water‐leachable ions were highest in the soil immediately beneath the tsunami deposit and then decreased gradually with depth. Because of its finer texture and higher organic content, the soil has a higher water‐holding capacity than the sandy tsunami deposit. This distribution suggests that ions derived from the tsunami quickly penetrated the sand layer and became concentrated in the underlying soil. In the samples collected in 2014, concentrations of water‐leachable ions were very low in both soil and sand. We attribute the decrease in ion concentrations to post‐tsunami rainfall, seepage, and seasonal changes in groundwater level. Although water‐leachable ions derived from seawater were concentrated in the soil beneath the tsunami deposit following the tsunami inundation, they were not retained for more than a few years. To elucidate the behavior of geochemical characteristics associated with tsunamis, further research on organic‐rich muddy deposits (muddy tsunami deposits and soils beneath sandy tsunami deposits) as well as sandy tsunami deposits is required.  相似文献   

14.
The stratigraphy of tsunami deposits along the Japan Sea, southwest Hokkaido, northern Japan, reveals tsunami recurrences in this particular area. Sandy tsunami deposits are preserved in small valley plains, whereas gravelly deposits of possible tsunami origin are identified in surficial soils covering a Holocene marine terrace and a slope talus. At least five horizons of tsunami events can be defined in the Okushiri Island, the youngest of which immediately overlies the Ko‐d tephra layer (1640 AD) and was likely formed by the historical Oshima‐Ohshima tsunami in 1741 AD. The four older tsunami deposits, dated using accelerator mass spectrometry 14C, were formed at around the 12th century, 1.5–1.6, 2.4–2.6, and 2.8–3.1 ka, respectively. Tsunami sand beds of the 1741 AD and circa 12th century events are recognized in the Hiyama District of Hokkaido Island, but the older tsunami deposits are missing. The deposits of these two tsunamis are found together at the same sites and distributed in regions where wave heights of the 1993 tsunami (Hokkaido Nansei‐oki earthquake, Mw = 7.7) were less than 3 m. Thus, the 12th century tsunami waves were possibly generated near the south of Okushiri Island, whereas the 1993 tsunami was generated towards the north of the island. The estimated recurrence intervals of paleotsunamis, 200–1100 years with an average of 500 years, likely represents the recurrence interval of large earthquakes which would have occurred along several active faults offshore of southwest Hokkaido.  相似文献   

15.
First, we investigated some aspects of tsunami–tide interactions based on idealized numerical experiments. Theoretically, by changing total ocean depth, tidal elevations influence the speed and magnitude of tsunami waves in shallow regions with dominating tidal signals. We tested this assumption by employing a simple 1-D model that describes propagation of tidal waves in a channel with gradually increasing depth and the interaction of the tidal waves with tsunamis generated at the channel's open boundary. Important conclusions from these studies are that computed elevations by simulating the tsunami and the tide together differ significantly from linear superposing of the sea surface heights obtained when simulating the tide and the tsunami separately, and that maximum tsunami–tide interaction depends on tidal amplitude and phase. The major cause of this tsunami–tide interaction is tidally induced ocean depth that changes the conditions of tsunami propagation, amplification, and dissipation. Interactions occur by means of momentum advection, bottom friction, and variable water flux due to changing total depth and velocity. We found the major cause of tsunami–tide interactions to be changing depth. Secondly, we investigate tsunami–tide interactions in Cook Inlet, Alaska, employing a high-resolution 2-D numerical model. Cook Inlet has high tides and a history of strong tsunamis and is a potential candidate for tsunami impacts in the future. In agreement with previous findings, we find that the impacts of tsunamis depend on basin bathymetries and coastline configurations, and they can, in particular, depend on tsunami–tide interactions. In regions with strong tides and tsunamis, these interactions can result in either intensification or damping of cumulative tsunami and tide impacts, depending on mean basin depth, which is regulated by tides. Thus, it is not possible to predict the effect of tsunami–tide interaction in regions with strong tides without making preliminary investigations of the area. One approach to reduce uncertainties in tsunami impact in regions with high tides is to simulate tsunamis together with tidal forcing.  相似文献   

16.
Erosion and Sedimentation from the 17 July, 1998 Papua New Guinea Tsunami   总被引:1,自引:0,他引:1  
— This paper describes erosion and sedimentation associated with the 17 July 1998 Papua New Guinea tsunami. Observed within two months of the tsunami, distinct deposits of a layer averaging 8-cm thick of gray sand rested on a brown muddy soil. In most cases the sand is normally graded, with more coarse sand near the base and fine sand at the top. In some cases the deposit contains rip-up clasts of muddy soil and in some locations it has a mud cap. Detailed measurements of coastal topography, tsunami flow height and direction indicators, and deposit thickness were made in the field, and samples of the deposit were collected for grain-size analysis in the laboratory. Four shore-normal transects were examined in detail to assess the shore-normal and along shore distribution of the tsunami deposit. Near the shoreline, the tsunami eroded approximately 10–25 cm of sand from the beach and berm. The sandy layer deposited by the tsunami began 50–150 m inland from the shoreline and extended across the coastal plain to within about 40 m of the limit of inundation; a total distance of up to 750 m from the beach. As much as 2/3 of the sand in the deposit originated from offshore. Across most of the coastal plain the deposit thickness and mean grain size varied little. In the along-shore direction the deposit thickness varied with the tsunami wave height; both largest near the entrance to Sissano Lagoon.  相似文献   

17.
The East Japan tsunami of 11 March 2011 propagated more than 100 km upstream in the Columbia River. Visual analysis of its records along the river suggests that the tsunami propagation was strongly affected by tidal conditions. A numerical model of the lower Columbia River populated with tides and a downstream current was developed. Simulations of the East Japan tsunami propagating up the tidal river reproduced the observed features of tsunami waveform transformation, which did not emerge in simulations of the same wave propagating in a quiescent-state river. This allows us to clearly attribute those features to nonlinear interaction with the tidal river environment. The simulation also points to possible amplification of a tsunami wave crest propagating right after the high tide, previously deduced from the recordings of the 1964 Alaska tsunami in the river.  相似文献   

18.
— Simulation of tsunami propagation and runup of the 1998 Papua New Guinea (PNG) earthquake tsunami using the detailed bathymetry measured by JAMSTEC and adding bathymetric data at depths less than 60 m is carried out, reproducing the tsunami energy focus into Warapu and Arop along the Sissano Lagoon. However, the computed runup heights in the lagoon are still lower than those measured. Even if the error in estimating the fault parameters is taken into consideration, computational results are similar. Analysis by the wave ray method using several scenarios of the source size of the tsunami and location by the wave ray method suggests that a source characterized by small size in water 1,000-m deep approximately 25 km offshore the lagoon, best fits the arrival determined from the interviews with eyewitnesses. A two-layer numerical model simulating the interaction of the tsunami with a landslide is employed to study the behavior of a landslide-generated tsunami with different size sand depths of the initial slide just outside the lagoon. A landslide model with a volume of 4–8 × 109 m3 is selected as the best in order to reproduce the distribution of the measured tsunami runup in the lagoon. The simulation of a tsunami generated in two stages, fault and landslide, could show good agreement with the runup heights and distribution of the arrival time, but a time gap of around 10 minutes remains, suggesting that a tsunami generated by the mainshock at 6:49 PM local time is too small for people to notice, and the following tsunami triggered by landslide or mass movement near the lagoon about ten minutes after the mainshock attacked the coast and caused the huge damage.  相似文献   

19.
Tsunami induced by earthquake is an interaction problem between liquid and solid.Shallow-water wave equation is often used to modeling the tsunami,and the boundary or initial condition of the problem is determined by the displacement or velocity field from the earthquake under sea floor,usually no interaction between them is consid-ered in pure liquid model.In this study,the potential flow theory and the finite element method with the interaction between liquid and solid are employed to model the dynamic processes of the earthquake and tsunami.For model-ing the earthquake,firstly the initial stress field to generate the earthquake is set up,and then the occurrence of the earthquake is simulated by suddenly reducing the elastic material parameters inside the earthquake fault.It is dif-ferent from seismic dislocation theory in which the relative slip on the fault is specified in advance.The modeling results reveal that P,SP and the surface wave can be found at the sea surface besides the tsunami wave.The surface wave arrives at the distance of 600 km from the epicenter earlier than the tsunami 48 minutes,and its maximum amplitude is 0.55 m,which is 2 times as large as that of the sea floor.Tsunami warning information can be taken from the surface wave on the sea surface,which is much earlier than that obtained from the seismograph stations on land.The tsunami speed on the open sea with 3 km depth is 175.8 m/s,which is a little greater than that pre-dicted by long wave theory,(gh)1/2=171.5 m,and its wavelength and amplitude in average are 32 km and 2 m,respectively.After the tsunami propagates to the continental shelf,its speed and wavelength is reduced,but its amplitude become greater,especially,it can elevate up to 10 m and run 55 m forward in vertical and horizontal directions at sea shore,respectively.The maximum vertical accelerations at the epicenter on the sea surface and on the earthquake fault are 5.9 m/s2 and 16.5 m/s2,respectively,the later is 2.8 times the former,and therefore,sea water is a good shock  相似文献   

20.
Sediments left by coastal flooding have been observed worldwide and have been variously ascribed to the action of storm surges and tsunami waves. To date, no study has attempted to unequivocally establish on stratigraphical, sedimentological, and palaeoecological grounds the means by which these two different processes might be distinguished in coastal sedimentary sequences. This paper examines the evidence for historical storm surges and tsunamis and shows that both high magnitude events have been documented over the past 250 years in southwest England. Sand layers of varying thickness are present within Holocene lagoonal and peat sequences of several shallow lakes of the Scilly Isles. Detailed analysis of Big Pool, St Agnes, indicates that the basal peats date from around 1000 BP. Within the basal peats are numerous thin sand layers. Above the basal peat is an extensive sand layer 15 to 40 cm thick. The base of this latter layer probably dates from the early to mid 18th century. Particle size, grain surface morphology, diatom, and mineral magnetic studies are used to try and determine the most likely mode of deposition. The results of all analyses are inconclusive, but the weight of evidence suggests that the increasing frequency of thin sand layers in the upper part of the basal peat may be related to the increasing frequency and intensity of Atlantic storms during the Little Ice Age superimposed upon a rising sea level. The thick sand layer may have been deposited by the tsunami wave generated by the Lisbon earthquake of November 1,1755. Due to the difficulties in distinguishing depositional processes in coastal environments known to have been affected by storm surges and tsunami waves, it is suggested that generally accepted sedimentological techniques are inadequate for discriminating depositional processes in coastal environments.  相似文献   

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