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1.
We present a preliminary estimation of tsunami hazard associated with the Makran subduction zone (MSZ) at the northwestern Indian Ocean. Makran is one of the two main tsunamigenic zones in the Indian Ocean, which has produced some tsunamis in the past. Northwestern Indian Ocean remains one of the least studied regions in the world in terms of tsunami hazard assessment. Hence, a scenario-based method is employed to provide an estimation of tsunami hazard in this region for the first time. The numerical modeling of tsunami is verified using historical observations of the 1945 Makran tsunami. Then, a number of tsunamis each resulting from a 1945-type earthquake (M w 8.1) and spaced evenly along the MSZ are simulated. The results indicate that by moving a 1945-type earthquake along the MSZ, the southern coasts of Iran and Pakistan will experience the largest waves with heights of between 5 and 7 m, depending on the location of the source. The tsunami will reach a height of about 5 m and 2 m in northern coast of Oman and eastern coast of the United Arab Emirates, respectively.  相似文献   

2.
The Pacific coast, including the Kamchatka Peninsula, the Kuriles, the Sea of Japan, the Sea of Okhotsk, and the Bering Sea, is the main tsunami-prone area in Russia. The Far East tsunamis are much more frequent, extensive, and devastating than those in the Black, Caspian, Baltic, and White Sea coasts, as well as in major inland lakes of Baikal, Ladoga, etc. The tsunami catalog of the Russian Far East from 1737 to present lists 110 events with mainly near-field and few far-field sources (105 and 5 events, respectively). Most of the catalogued tsunamis (95 cases) were induced by earthquakes, and few events had volcanic (3), landsliding (2), meteorological (3), and unknown (2) triggers. Altogether there were eleven devastating tsunamis for the period of observations, with > 10 m heights, two of which were great events in 1737 and 1952, when the waves exceeded 20 m. The wave heights were in the range 2.5-10 m in fifteen hazardous tsunami events and within the tidal range (~ 1-2 m) in thirteen cases; the other events were small and detectable only instrumentally. Thus, the average recurrence times for tsunamis of different magnitudes in the Russian Pacific coast are 25 years for devastating events and 10-15 years for hazardous tsunamis; small tsunamis occur almost every year, according to statistics for the last sixty years collected at the regional network of tide stations. The topics discussed in the paper concern the completeness and reliability of the Far East catalog; distribution of tsunami events in space and time; correlation between the intensity of tsunami and the magnitude of the causative undersea earthquake; tsunami recurrence; tsunami warning; and long-term hazard assessment and mapping.  相似文献   

3.
A modern tsunami catalogue has been compiled for the region of Cyprus-Levantine Sea in which 24 certain or possible local tsunamis are listed from antiquity up to the present time, while six regional tsunamis, generated in the Hellenic arc, are documented which affected the region. Another set of 13 doubtful events not included in the catalogue are discussed. Tsunami intensities k and K were re-evaluated using the classic 6-grade and the new 12-grade intensity scales, respectively. The strongest tsunamis reported in the region of interest are those of 551 AD, 749, 1068, 1201, 1222, 1546 and 1759, all occurring along the Levantine coast from Gaza northward, with the exception of the 1222 wave which occurred in the Cyprean arc. The causative earthquakes, however, occur on land and are associated with the left-lateral strike-slip Levantine rift and, as such, remain unexplained. In this paper we speculate on the mechanism of these events. A second tsunami zone follows the Cyprean arc, where the situation of subaqueous seismogenic sources favours the generation of tsunamis by co-seismic fault displacements. Submarine or coastal earth slumping, however, may be an additional tsunamigenic component. Based on historical data, the average tsunami recurrence in the Cyprus-Levantine Sea region is roughly estimated to be around 30 years, 120 years and 375 years for moderate (k/K ≥ 2/3), strong (k/K ≥ 3/5) and very strong (k/K ≥ 5/8) events, respectively. The rate of tsunami occurrence equals 0.033, 8.3 × 10−3 and 2.7 × 10−3 events/year for intensity k/K ≥ 2/3, 3/5 and 5/8, respectively. For a Poissonian (random) process the probabilities of observing at least one moderate, strong or very strong tsunami are 0.28, 0.01 and 3 × 10−3 within 1 year, 0.81, 0.34 and 0.13 within 50 years and 0.96, 0.56 and 0.24 within 100 years, respectively. The tsunami potential in the Cyprus-Levantine Sea area is low relative to other Mediterranean tsunamigenic regions. However, the destructiveness of some historical events indicates the need to evaluate tsunami hazard by all available means. In addition, remote tsunamigenic sources, such as those of 1303 and 1481 in the eastern Hellenic arc, are able to threaten the coasts of the Cyprus-Levantine region and, therefore, such regional tsunamis should be taken into account in the evaluation of the tsunami risk of the region.  相似文献   

4.
A sudden disturbance in water level was recorded by hydrographs monitoring wells in the coastal city Dammam, Saudi Arabia on December 26, 2004. The water level was being recorded from the shallow (1–3 M deep) coastal aquifer at that time. In two wells, this disturbance was observed ~12 h after the Sumatra earthquake/tsunami event of December 26, 2004. The timing of this event is synchronous in two wells near the coast, but an inland well away from the coast line did not show any such disturbance. It is hypothesized that this disturbance, we call it the “shock event”, is resulted by sudden impact of tsunamis traveling in the Arabian Gulf from southeast toward northwest. As the tsunamis propagated, they suddenly impacted the coastal shallow groundwater aquifer resulting in the “shock event”.  相似文献   

5.
The tsunami of 26th December 2004 severely affected Yemen’s Socotra Island with a death at a distance of 4,600 km from the epicenter of the Magnitude 9.0 earthquake. Yemen allowed a detailed assessment of the far-field impact of a tsunami in the main propagation direction. The UNESCO mission surveyed 12 impacted towns on the north and south shores covering from the east to the west tip of Socotra. The international team members were on the ground in Yemen from 11 to 19 October 2006. The team measured tsunami run-up heights and inundation distances based on the location of watermarks on buildings and eyewitness accounts. Maximum run-up heights were typically on the order of 2–6 m. Each measurement was located by means of global positioning systems (GPS) and photographed. Numerous eyewitness interviews were recorded on video. The tsunami impact on Socotra is compared with other locations along the shores of the Indian Ocean.  相似文献   

6.
The tsunami inundation flows on Banda Aceh, Indonesia reached 5 km inland during the December 26, 2004, event and devastated most of the houses, buildings, and infrastructure along the coast and killed more than 167,000 people. The overland flows from the northwest coast and the west coast collided at Lampisang village approximately 3.7 km from Ulee Lheue (northwest coast) and 6.8 km from Lhok Nga (west coast) as reported by survivors. Inundation modeling based on the nonlinear shallow-water wave equations reproduces the inundation pattern and demonstrates a colliding of the overland flows. The model suggests that wave characteristics on the northwest coast of Banda Aceh were different from those on the waves that impacted upon the west coast. The areas, which experienced higher inundation levels, did not always experience greatest overland flow speeds, and the damage areas mostly coincide with the flow speed distribution rather than the runup and inundation depth.  相似文献   

7.
Coastal boulder deposits and chevrons are two features whose origin have triggered controversial discussions. Boulders are often used as indicators of past tsunamis and storms, with the former interpretation in many cases preferred due to the clast size. Chevrons, defined as large parabolic sand bodies, were previously attributed to (mega-)tsunami, potentially caused by oceanic impacts, because of their dimensions, height above sea level and alignment of the central axis. This study documents that chevrons along the Quobba coast in Western Australia are parabolic dunes and not related to tsunami inundation; their age is consistent with an arid period at about 3·9 to 2·3 ka when the sea level was 1 to 2 m higher than today. The internal age distribution proves an inland migration. Weakly developed soil horizons represent phases of intermittent dune stabilization and later reactivation. The calculated velocities required for wind transport and the prevailing wind directions are consistent with on-site meteorological parameters. The boulders at Quobba are most likely to be remnants of in situ platform denudation that produces shell hash, coral clasts and boulders. An unknown portion of the boulders was certainly moved by tropical cyclones. A previously proposed tsunami origin is unsustainable because the observed features can be explained by processes other than tsunamis. Boulders were tilted during gravitative platform collapse, standing water caused dissolution of the boulder bottoms, creating ‘pseudo-rockpools’, consequently not applicable as upside-down criteria, and ages of attached encrusting organisms document their colonization at higher sea level and (sub)recent frequent inundation by wave splash during rough seas.  相似文献   

8.
A new model to calculate tsunami travel times in the Andaman Sea region has been developed. The model specifically provides more accurate travel time estimates for tsunamis propagating to Patong Beach on the west coast of Phuket, Thailand. More generally, the model provides better understanding of the influence of the accuracy and resolution of bathymetry data on the accuracy of travel time calculations. The dynamic model is based on solitary wave theory, and a lookup function is used to perform bilinear interpolation of bathymetry along the ray trajectory. The model was calibrated and verified using data from an echosounder record, tsunami photographs, satellite altimetry records, and eyewitness accounts of the tsunami on 26 December 2004. Time differences for 12 representative targets in the Andaman Sea and the Indian Ocean regions were calculated. The model demonstrated satisfactory time differences (<2 min/h), despite the use of low resolution bathymetry (ETOPO2v2). To improve accuracy, the dynamics of wave elevation and a velocity correction term must be considered, particularly for calculations in the nearshore region.  相似文献   

9.
In the seventeenth century, two tsunamis that were generated by earthquakes on the Kuril–Kamchatka subduction zone inundated the eastern coast of Hokkaido, northern Japan. Stratigraphic evidence for these two tsunamis and related land-level change in coastal Hokkaido consists of two landward-thinning sand layers in the sediments of Lake Tokotan, a coastal lagoon on the Hokkaido coast. The marine origin of these sand layers is indicated by the presence of brackish–marine diatoms. The rarity and high degree of fragmentation of diatom valves suggests that the sands were transported in a short time over a considerable distance. Tsunamis at this site were probably generated by great earthquakes along the Kuril–Kamchatka Trench. Volcanic ash deposits lying just above the sands suggest that tsunamis occurred in the late 17th century. Tsunamis during the historic period are not recorded in Lake Tokotan, which suggests that the sand layers were deposited by tsunamis substantially larger than historic tsunamis.  相似文献   

10.
The cyclone wave parameters are predicted using Young’s parametric hurricane wave prediction model. The input cyclone tracks for this work are obtained from Fleet Naval Meteorology and Oceanography Center, USA. Extreme value analysis is carried out to obtain the wave heights and periods for 1 in 5, 10, 50 and 100 years return periods, respectively. The deep-water hindcast wave corresponding to 100 years from probable directions are allowed to propagate to Visakhapatnam coastal waters using nearshore spectral wind-wave mode. The offshore wave height for one in 100-year return period is 11.9 m, and the corresponding nearshore wave height at 10-m water depth varies between 4.6 and 5.6 m depending on the directional spreading. Weibull distribution is chosen to fit the 24 cyclonic data sets over a total period of 30 years (September 1972 to November 2002). This paper demonstrates usefulness of Young’s wave model for deep-water extreme wave hindcasting. Further, the results of the present study would be highly useful for assessing the design wave height for Visakhapatnam coast.  相似文献   

11.
In this study, a numerical modeling system based on the dispersion–correction finite difference scheme equipped with a grid-nesting scheme is constructed. The model is applied to simulate the propagation of three historical tsunami events that attacked the east coast of Korea. The calculated free-surface displacements for the cases of the 1983 Akita and the 1993 Okushiri tsunamis are compared with the observations at four tidal stations along the east coast of Korea. The comparison shows that the results agree well with the observations. The analyses of the simulated results show that underwater topography, such as submerged rises and ridges, plays an important role in the propagation of tsunamis in this region.  相似文献   

12.
Tide gauge data were used to identify the occurrence, characteristics, and cause of tsunamis of meteorological origin (termed ‘meteotsunamis’) along the Western Australian coast. This is the first study to identify meteotsunamis in this region, and the results indicated that they occur frequently. Although meteotsunamis are not catastrophic to the extent of major seismically induced basin-scale events, the wave heights of meteotsunamis examined at some local stations in this study were higher than those recorded through seismic tsunamis. In June 2012, a meteotsunami contributed to an extreme water-level event at Fremantle, which recorded the highest water level in over 115 years. Meteotsunamis (wave heights >0.4 m, when the mean tidal range in the region is ~0.5 m) were found to coincide with thunderstorms in summer and the passage of low-pressure systems during winter. Spectral analysis of tide gauge time series records showed that existing continental seiche oscillations (periods between 30 min and 5 h) were enhanced during the meteotsunamis, with a high proportion of energy transferred to the continental shelf oscillation period. Three recent meteotsunami events (22 March 2010, 10 June 2012, and 7 January 2013) two due to summer thunderstorms and one due to a winter frontal system were chosen for detailed analysis. The meteotsunami amplitudes were up to a factor 2 larger than the local tidal range and sometimes contributed up to 85 % of the non-tidal water signal. A single meteorological event was found to generate several meteotsunamis along the coast, up to 500 km apart, as the air pressure disturbance propagated over the continental shelf; however, the topography and local bathymetry of the continental shelf defined the local sea-level resonance characteristics at each location. With the available data (sea level and meteorological), the exact mechanisms for the generation of the meteotsunamis could not be isolated.  相似文献   

13.
The Ministry of Shipping desires to revise the inland vessels’ limit (IVL) notification based on scientific rationale to improve the safety of vessels and onboard personnel. The Mormugao port region extending up to the Panaji was considered for this pilot study. Measured winds and wave parameters (AWS and moored buoy) as well as NCEP re-analysis and NCMRWF winds were used for the analysis and input to regional and local models. The results of wave model were validated with measured significant wave heights (SWHs) and the comparison shows a good match. The analysis indicates that SWHs do not exceed 2.0 m during non-monsoon months, and in monsoon months exceed 5.0 m, and even 7.0 m, especially during extreme events. In order to draw IVL contours for Goa coastal region, local model was set up and nearshore waves were simulated for the period May 2004–May 2005. Based on the nearshore SWH distribution, IVL contours have been fixed for the Mormugao port and Panaji coastal regions.  相似文献   

14.
The Tsunami of August 17, 1999 in Izmit Bay,Turkey   总被引：2，自引：0，他引：2  
Altinok  Y.  Tinti  S.  Alpar  B.  Yalçiner  A. C.  Ersoy  Ş  Bortolucci  E.  Armigliato  A. 《Natural Hazards》2001,24(2):133-146
The Kocaeli 1999 Earthquake with an Mw = 7.4 caused major hazards throughout the NW of Turkey from Tekirdag to Bolu. Historical data indicates that some of the earthquakes around Izmit Bay have caused tsunamis. In this study, tsunami research for the Kocaeli 1999 Earthquake has been made also taking into consideration historical data. In this research more than about 70 data at 35 localities have been used to determine the tsunami evidences in the bay. Coastal observations indicated runups which were ranging from 1 to 2.5 m along the shores. However, the wave runups are more complex along the south coast due to the presence of coastal landslides (Deirmendere, Halidere, Ulasli, Karamürsel) and subsided areas (Kavakli to Yeniköy) along the shore. West of Yalova, evidence of tsunami rapidly diminished. In addition, possible tectonic mechanism has been determined by using 33 single-channel high-resolution digital seismic reflection profiles which were acquired following the Kocaeli 1999 Earthquake. As a result it has been determined that the Kocaeli Earthquake has created tsunami in Izmit Bay.  相似文献   

15.
This paper discusses the applications of linear and nonlinear shallow water wave equations in practical tsunami simulations. We verify which hydrodynamic theory would be most appropriate for different ocean depths. The linear and nonlinear shallow water wave equations in describing tsunami wave propagation are compared for the China Sea. There is a critical zone between 400 and 500 m depth for employing linear and nonlinear models. Furthermore, the bottom frictional term exerts a noticeable influence on the propagation of the nonlinear waves in shallow water. We also apply different models based on these characteristics for forecasting potential seismogenic tsunamis along the Chinese coast. Our results indicate that tsunami waves can be modeled with linear theory with enough accuracy in South China Sea, but the nonlinear terms should not be neglected in the eastern China Sea region.  相似文献   

16.
Pelinovsky  Efim  Kharif  Christian  Riabov  Igor  Francius  Marc 《Natural Hazards》2002,25(2):135-159
The problem of tsunami-risk for the French coast of the Mediterraneanis discussed. Historical data of tsunami manifestation on the French coast are described and analysed.Numerical simulation of potential tsunamis in the Ligurian Sea is done and the tsunami wave heightdistribution along the French coast is calculated. For the earthquake magnitude 6.8 (typical value forMediterranean) the tsunami phenomenon has a very local character. It is shown that the tsunami tide-gaugerecords in the vicinity of Cannes–Imperia present irregularoscillations with characteristic periodof 20–30 min and total duration of 10–20h.Tsunami propagating from the Ligurian sea to the west coastof France have significantly lesser amplitudes and they are more low-frequency (period of 40–50min).The effect of far tsunamis generated in the southern Italy and Algerian coast is studied also, thedistribution of the amplitudes along the French coast for far tsunamis is more uniform.  相似文献   

17.
We present the results of work on the compilation of a fuller and more comprehensive historical catalogue of earthquakes and tsunamis in the basin of the Black Sea and the Sea of Azov, an area of primary importance for the Russian Federation. In the 20th century, there were no significant tsunamis in the Black Sea; therefore, its coast was not considered tsunami-prone. A systematic search for new data sources, a revision of earlier ones, and the use of new approaches to the identification of tsunamigenic events resulted in a more than doubling of the number of known tsunamigenic events in this basin, bringing it up to 50. The total length of the new tsunami catalogue reached 3000 years, which makes it the second longest after the Mediterranean tsunami catalogue (about 4000 years). Taking into account the seismotectonic features of the Black Sea region, we processed data on historical tsunamis and analyzed the geographical and temporal distributions of their sources. For all tsunamigenic events we performed a parameterization of available information about their sources and coastal manifestations, evaluated the tsunami intensity based on the Soloviev-Imamura scale, and proposed a classification of tsunami and tsunami-like water wave disturbances based on their genesis. Tsunami run-up heights, inland penetration, and damage were estimated with regard for the newly found data. Among the identified historical events, there are devastating tsunamis with run-ups of 4-5 m, sometimes up to 6-8 m, which resulted in disastrous consequences for several ancient cities (Dioscuria, Sebastopolis, Bizone, and Panticapaeum) and many coastal settlements. Expert assessments of the most tsunami-prone areas of the coasts are given.  相似文献   

18.
Deposits from as many as 50 large tsunamis during the last 7000 years are preserved on the Pacific coast of the Kamchatka Peninsula near the mouth of the Zhupanova River, southern Kronotskiy Bay. These deposits are dated and correlated using Holocene marker tephra layers. The combined, preserved record of tsunami deposits and of numerous marker tephras on Kamchatka offers an unprecedented opportunity to study tsunami frequency. For example, from the stratigraphy along southern Kronotskiy Bay, we estimate frequency of large tsunamis (>5 m runup). In the last 3000 years, the minimum frequency is about one large tsunami per 100 years, and the maximum about one large tsunami per 30 years; the latter frequency occurred from about 0 to 1000 A.D. This time interval corresponds to a period of increased seismicity and volcanic activity that appears to be recorded in many places on the Kamchatka Peninsula.  相似文献   

19.
A 97-day-long record on waves and currents was obtained using wave rider buoy and current meter moored at 2.5 km off Gopalpur from 19 May to 23 August 2008 representing southwest monsoon months. A Valeport tide gauge was used to record water level at Gopalpur port. Simultaneously, beach profiles at 4 transects were monitored using real-time kinematic (RTK) global positioning system (GPS). A total of 636,167 waves were analyzed for the period; a range of 3,200–9,700 waves approach the coast in an individual day. During the study, unusual characteristics of wave were observed on July 29, 2008, with a magnitude of significant wave height, Hs = 2.85 m, maximum wave height, Hmax = 5.22 m, and peak wave period, Tp = 10.2 s, and on August 11, 2008, with Hs = 2.28 m, Hmax = 5.37 m, and Tp = 11.1 s. Significant beach loss was noticed during these periods, and severe erosion was recorded on August 1, 2008. Beach profile data indicates that 18–58 cu. m/m sediment was lost during the study period. The paper provides an overview of the statistical analysis of wave heights, periods, direction, and spectral energy density and explains the cause of coastal erosion and loss of sediment.  相似文献   

20.
Meteorological tsunamis are frequently observed in different tide stations at the southeastern coast of South America. They are associated with the occurrence of atmospheric gravity waves during the passages of cold fronts over the Buenos Aires Province continental shelf. On the other hand, storm surges are also frequent in the region, and they are associated with strong and persistent southerlies, which are also frequent during cold front passages. The impact of meteorological tsunamis in coastal erosion and in the statistics of storm surge trends is discussed in this paper. For this study, fifteen meteorological tsunamis (with maximum wave heights higher than 0.20 m), seven of them simultaneous to the occurrence of storm surge events (with extreme levels higher than |±0.60 m|), are selected from April 2010 to January 2013. The impact of meteorological tsunamis in the storm erosion potential index (SEPI) is evaluated. Not significant differences are obtained between SEPI calculated with and without filtering the meteorological tsunami signal from the storm surge data series. Moreover, several experiments are carried out computing SEPI from synthetic sea level data series, but very low changes (lower than 4 %) are also obtained. It is concluded that the presence of moderate meteorological tsunamis on sea level records would not enhance this index at the Buenos Aires Province coast. On the other hand, taking into account that meteorological tsunamis can reach up the 20–30 % of the storm surge height, it was concluded that the statistics of storm surge trends (and their uncertainties) should be revised for Mar del Plata data series.  相似文献   

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