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1.
Comparison of linear and nonlinear shallow wave water equations applied to tsunami waves over the China Sea 总被引：4，自引：0，他引：4
Yingchun Liu Yaolin Shi David A. Yuen Erik O. D. Sevre Xiaoru Yuan Hui Lin Xing 《Acta Geotechnica》2009,4(2):129-137
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
2.
Postglacial rebound is a major geological process which plays an important role in many areas in the earth sciences. Up to
now, most of the images derived from studies of the glacial isostatic adjustment phenomenon have been concerned with surface
signatures, such as the uplift and gravity anomalies and not much attention has been paid on the dynamical responses in the
mantle. We will make use of the 3D visualization package Amira to depict both the external and internal deformation histories
of the transient viscoelastic flow inside the mantle induced by postglacial uplift. Of particularly great interest are the
transient displacement fields and shear heating inside the mantle. This same visualization technology can be brought to bear
in the future for visualizing tsunami waves in ocean basins excited by earthquakes, volcanic eruptions and InSAR images. We
have also integrated the visualization results into the Google Earth virtual globe by combining this scheme with the Amira
package to provide a better geographical and dynamical context.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
3.
Seaquake is a phenomenon where there are water disturbance at the sea, caused by earthquake or submarine eruption. The scope of this study focuses on tsunami simulation due to Manila Trench and Sulu Trench seaquake which is prone to harm Malaysia offshore areas. Manila Trench is a highly potential earthquake source that can generate tsunami in South China Sea. Meanwhile, Sulu Trench could be a threat to east of Sabah offshore areas. In this study, TUNA-M2 model was utilized to perform tsunami simulation at South China Sea and Sulu Sea. TUNA-M2 model applied Okada source model to create tsunami generation due to earthquake. It utilized linear shallow water equation during tsunami propagation with its radiant boundary condition. Five simulations performed at each study region. Forecast points at South China Sea areas were divided into three separate locations which are at the Peninsular Malaysia, west of Sabah and Sarawak offshore areas. Forecast points at Sulu Sea were focused at the east of Sabah offshore areas. This paper will present the simulation results of tsunami wave height and arrival time at various forecast points. The findings of this study show that the range of tsunami wave height at Sulu Sea is higher than that of South China Sea. The tsunami arrival time at Sulu Sea is less than South China Sea. It can be concluded that Sulu Sea poses worse tsunami threat than South China Sea to the Malaysian offshore areas. 相似文献
4.
Use of tsunami waveforms for earthquake source study 总被引：1，自引：0，他引：1
Tsunami waveforms recorded on tide gauges, like seismic waves recorded on seismograms, can be used to study earthquake source processes. The tsunami propagation can be accurately evaluated, since bathymetry is much better known than seismic velocity structure in the Earth. Using waveform inversion techniques, we can estimate the spatial distribution of coseismic slip on the fault plane from tsunami waveforms. This method has been applied to several earthquakes around Japan. Two recent earthquakes, the 1968 Tokachi-oki and 1983 Japan Sea earthquakes, are examined for calibration purposes. Both events show nonuniform slip distributions very similar to those obtained from seismic wave analyses. The use of tsunami waveforms is more useful for the study of unusual or old earthquakes. The 1984 Torishima earthquake caused unusually large tsunamis for its earthquake size. Waveform modeling of this event shows that part of the abnormal size of this tsunami is due to the propagation effect along the shallow ridge system. For old earthquakes, many tide gauge records exist with quality comparable to modern records, while there are only a few good quality seismic records. The 1944 Tonankai and 1946 Nankaido earthquakes are examined as examples of old events, and slip distributions are obtained. Such estimates are possible only using tsunami records. Since tide-gauge records are available as far back as the 1850s, use of them will provide unique and important information on long-term global seismicity. 相似文献
5.
Prognostic characteristics of tsunamis in the East (Japan) Sea based on numerical simulations are investigated by using linear
long wave theory. Due to the lack of observed data, the concept of the synthetic catalogue is applied to generate possible
tsunami scenarios. It includes four real events that occurred in the East (Japan) Sea during the 20th century, 24 hypothetical
tsunamigenic earthquakes located in the gap zones of the seismic map, and 76 idealized model ‘hydrodynamic’ sources covering
the eastern part of the East (Japan) Sea uniformly. The tsunami wave height distributions along the East (Japan) Sea coastline
due to these hypothetical events are computed. From the geographical distributions of tsunami wave height for all possible
events, it is found that there exist several coastal locations where the tsunami risk is relatively lower than in other zones.
The relation between the maximal value of the tsunami height and its average value is analyzed. It is found that the maximal
tsunami height does not exceed the mean wave height times a constant. The uniform bounded curve for all areas can be obtained
if the mean wave height is replaced by the modified mean wave height (1/3 of largest waves). The problem of quantitative definition
of the prognostic tsunami wave height for each location based on the data from the synthetic catalogue is discussed. The results
of tsunami wave height analysis based on the synthetic catalogue can be used as a tool for coastal disaster mitigation planning. 相似文献
6.
Historical tsunami records in the South China Sea are collected and analyzed in this paper. There have been about 54 tsunamis in the South China Sea since 1076. The impacts of the transoceanic tsunamis on the southeast coast of China are weak. However, the regional tsunamis in the South China Sea bring varying degrees of influence to the south coast of China, which occurred about 18 times. By the analysis of the potential tsunami sources in the South China Sea, numerical simulations of tsunami induced in the Manila Trench are carried out. It is found that the tsunami wave height is small near Haikou if the general earthquake tsunami occurred. But the tsunami wave height is large when a giant earthquake of M9.3 occurred. If this extreme situation arises, the impacts to the coast of Haikou will be serious. 相似文献
7.
At time of the 1983 Japan Sea tsunami, waves in the form of a bore ascended many rivers. In some cases, bores had the form of one initial wave with a train of smaller waves, and in other cases, such a wave train did not appear and only a step with a flat water surface behind was observed. In the present study, it is clarified that both undular-type and nonundular-type bores can be recognized as solutions of the KdV-Burger's equation which was introduced by Johnson in 1972. Numerically obtained analytical solutions and results of laboratory experiments are compared. 相似文献
8.
Simulation of the Arabian Sea Tsunami propagation generated due to 1945 Makran Earthquake and its effect on western parts of Gujarat (India) 总被引：1，自引：1，他引：0
The 1945 Tsunami generated due to Makran Earthquake in the Arabian Sea was the most devastating tsunami in the history of
the Arabian Sea and caused severe damage to property and loss of life. It occurred on 28th November 1945, 21:56 UTC (03:26
IST) with a magnitude of 8.0 (M
w), originating off the Makran Coast of Pakistan in the Arabian Sea. It has impacted as far as Mumbai in India and was noticed
up to Karvar Coast, Karnataka. More than 4,000 people were killed as a result of the earthquake and the tsunami. In this paper
an attempt is made for a numerical simulation of the tsunami generation from the source, its propagation into the Arabian
Sea and its effect on the western coast of India through the use of a numerical model, referred to as Tunami-N2. The present
simulation is carried out for a duration of 300 min. It is observed from the results that the simulated arrival time of tsunami
waves at the western coast of India is in good agreement with the available data sources. The paper also presents run-up elevation
maps prepared using Shuttle Radar Topographic Mission (SRTM) data, showing the possible area of inundation due to various
wave heights along different parts of the Gujarat Coast. Thus, these results will be useful in planning the protection measures
against inundation due to tsunami and in the implementation of a warning system. 相似文献
9.
Mark D. Bateman Tim C. Kinnaird Jon Hill Robert A. Ashurst Jenna Mohan Rebecca B. I. Bateman Ruth Robinson 《Boreas: An International Journal of Quaternary Research》2021,50(4):1059-1078
The Storegga tsunami, dated in Norway to 8150±30 cal. years BP, hit many countries bordering the North Sea. Run-ups of >30 m occurred and 1000s of kilometres of coast were impacted. Whilst recent modelling successfully generated a tsunami wave train, the wave heights and velocities, it under-estimated wave run-ups. Work presented here used luminescence to directly date the Storegga tsunami deposits at the type site of Maryton, Aberdeenshire in Scotland. It also undertook sedimentological characterization to establish provenance, and number and relative power of the tsunami waves. Tsunami model refinement used this to better understand coastal inundation. Luminescence ages successfully date Scottish Storegga tsunami deposits to 8100±250 years. Sedimentology showed that at Montrose, three tsunami waves came from the northeast or east, over-ran pre-existing marine sands and weathered igneous bedrock on the coastal plain. Incorporation of an inundation model predicts well a tsunami impacting on the Montrose Basin in terms of replicate direction and sediment size. However, under-estimation of run-up persisted requiring further consideration of palaeotopography and palaeo-near-shore bathymetry for it to agree with sedimentary evidence. Future model evolution incorporating this will be better able to inform on the hazard risk and potential impacts for future high-magnitude submarine generated tsunami events. 相似文献
10.
Flood risk curves and uncertainty bounds 总被引：7，自引：5，他引：2
The Scotia Arc is one of two regions in the Atlantic Ocean with greater potential for tsunami generation from seismic and
volcanic sources. A numerical modeling study was undertaken to determine tsunami generation from postulated sources along
the Arc and tsunami wave amplification or attenuation along the Patagonian continental shelf. Sea level oscillation represented
by a simple sinusoidal wave function applied at the boundary of the numerical grid, which simulated the tsunami entering the
computational domain, was implemented as forcing. The validation of this model was carried out by comparing the maximum amplitudes
recorded and simulated at Santa Teresita and Mar del Plata (Buenos Aires province) after the occurrence of earthquake and
subsequent tsunami in Sumatra (December 2004). From numerical simulations it can be seen that the tsunami propagation is highly
affected by bathymetric refraction on the Patagonian continental shelf and the wave amplitude is significantly attenuated
on the inner continental shelf. Maximum amplifications were obtained around Malvinas (Falkland) Islands and Burdwood bank
because the wave propagates almost without refracting and the shoaling effect is highly significant there. 相似文献
11.
On 28 February 1969, the coasts of Portugal, Spain and Morocco were affected by sea waves generated by a submarine earthquake (Ms = 7.3) with its epicenter located off Portugal. The propagation of this tsunami has been simulated by a finite element numerical model solving the Boussinesq equations. These equations have been discretized using the finite element Galerkin method and a Crank–Nicholson scheme in time. The model is validated by investigating the propagation of a solitary wave over a flat bottom. The grid sizes for the 1969 event have been determined by one-dimensional tests offshore and in shallow water regions. The two-dimensional simulation of the 1969 tsunami is carried out using the hydraulic source calculated from the geophysical model of Okada and seismic parameters of Fukao. The modeled waves are compared with the recorded ones with respect to travel times, maximum amplitudes and periods of the signal. The comparison between Boussinesq and shallow-water models shows that the effects of frequency dispersion are minor. Good agreement is found for most of the studied gauges. 相似文献
12.
Characteristics of Tsunamis Propagating over Oceanic Ridges: Numerical Simulation of the 1996 Irian Jaya Earthquake Tsunami 总被引：1，自引：0，他引：1
The 1996 Irian Jaya earthquake tsunami was simulated by using the numerical model based on the linear long wave theory including Coriolis force in the spherical coordinate system. The numerical modeling result at Chichijima is in good agreement with the observed tide gauge data. The distinctive oscillation at Chichijima can be interpreted as the formation of boundary waves, so called ridge waves that are excited on the South-Honshu ridge. The mechanism of tsunami propagation trapped on an oceanic ridge is analyzed with the simple ridge model. The result explains the characteristics of ridge waves excited on theSouth-Honshu ridge. 相似文献
13.
14.
We derive an asymptotic equation governing the trans-ocean propagation of tsunami from source to the continental shelf. Focus is on disturbances originated from a slender fault of finite length. The variable sea depth is assumed to consist of a slowly varying mean and random fluctuations. The method of multiple scales is used to derive a Kadomtsev–Petviashvili equation with variable coefficients. Modifications by one- and two-dimensional random irregularities are shown to affect the wave speed, dissipation and additional dispersion. The result can be used to facilitate physical insight with modest numerical efforts. 相似文献
15.
The Gardner equation is an extension of the Korteweg–de Vries (KdV) equation. It exhibits basically the same properties as
the classical KdV, but extends its range of validity to a wider interval of the parameters of the internal wave motion for
a given environment. In this paper, we derive exact solitary wave solutions for the generalized Gardner equation that includes
nonlinear terms of any order. Unlike previous studies, the exact solutions are derived without assuming their mathematical
form. Illustrative examples for internal solitary waves are also provided. The traveling wave solutions can be used to specify
initial data for the incident waves in internal waves numerical models and for the verification and validation of the associated
computed solutions. 相似文献
16.
The tsunami of 2004 in the Indian Ocean transported thousands of meters-long boulders shoreward at Pakarang Cape, Thailand. We investigated size, position and long axis orientation of 467 boulders at the cape. Most of boulders found at the cape are well rounded, ellipsoid in shape, without sharp broken edges. They were fragments of reef rocks and their sizes were estimated to be < 14m3 (22.7t). The distribution pattern and orientation of long axis of boulders reflect the inundation pattern and behavior of the tsunami waves. It was found that there is no clear evidence indicating monotonous fine/coarse shoreward trends of these boulders along each transect line. On the other hand, the large boulders were deposited repeatedly along the three arcuate lines at the intertidal zone with a spacing of approximately 136m interval. This distribution pattern may suggest that long-lasting oscillatory flows might have repositioned the boulders and separated the big ones from small. No boulders were found on land, indicating that the hydraulic force of the tsunami wave rapidly dissipated on reaching the land due to the higher bottom friction and the presence of a steep slope. We further conducted numerical calculation of tsunami inundation at Pakarang Cape. According to the calculation, the sea receded and the major part of the tidal bench (area with boulders at present) was exposed above the sea surface before the arrival of the first tsunami wave. The first tsunami wave arrived at the cape from west to east at approximately 130min after the tsunami generation, and then inundated inlands. Our calculation shows that tsunami wave was focused around the offshore by a small cove at the reef edge and spread afterwards in a fan-like shape on the tidal bench. The critical wave velocities necessary to move the largest and average-size boulders by sliding can be estimated to be approximately 3.2 and 2.0m/s, respectively. The numerical result indicates that the maximum current velocity of the first tsunami wave was estimated to be from 8 to 15m/s between the reef edge and approximately 500m further offshore. This range is large enough for moving even the largest boulder shoreward. These suggest that the tsunami waves that were directed eastward, struck the reef rocks and coral colonies, originally located on the shallow sea bottom near the reef edge, and detached and transported the boulders shoreward. 相似文献
17.
Analysis of Blast Wave Interaction with a Rock Joint 总被引：8，自引：3，他引：5
The interaction between rock joints and blast waves is crucial in rock engineering when rock mass is suffered from artificial or accidental explosions, bursts or weapon attacks. Based on the conservation of momentum at the wave fronts and the displacement discontinuity method, quantitative analysis for the interaction between obliquely incident P- or S-blast wave and a linear elastic rock joint is carried out in the present study, so as to deduce a wave propagation equation. For some special cases, such as normal or tangential incidence, rigid or weak joint, the analytical solution of the stress wave interaction with a rock joint is obtained by simplifying the wave propagation equation. By verification, it is found that the transmission and reflection coefficients from the wave propagation equation agree very well with the existing results. Parametric studies are then conducted to evaluate the effects of the joint stiffness and incident waves on wave transmission and reflection. The wave propagation equation derived in the present study can be straightforwardly extended for different incident waveforms and nonlinear rock joints to calculate the transmitted and reflected waves without mathematical methods such as the Fourier and inverse Fourier transforms. 相似文献
18.
土层场地对地震动的影响明显,研究成层场地局部复杂地形的波动场特性,对于抗震设防具有重要意义。基于土-结构相互作用理论,含有局部复杂地形的成层场地,可分解成广义结构（即近场复杂地形及其周围土体）和具有规则开挖边界的成层无限地基（即远场）。远场的格林函数可通过精细积分求解频域-波数域内的对偶波动方程获得,利用傅里叶逆变换得到频域-空间域内的柔度矩阵。近场可采用比例边界有限元进行模拟,通过高性能连分式的传递边界求解动刚度。自由场波动可通过传递矩阵法求得,将动刚度和自由场波动位移代入控制方程即可得到散射场的动力响应。数值算例验证了方法的准确性,并利用提出的方法讨论含有软夹层场地局部复杂场地的波动场特性。 相似文献
19.
Indonesia is one country in the world featuring a complex tectonic structure. This condition makes earthquakes often occur in many areas of this country and as an earthquake rages beneath the sea, it will potentially trigger tsunami. One of the areas in Indonesia with a high seismic activity is Sulawesi region particularly in the Sulawesi Sea subduction zone, making it important to carry out a study on the potential tsunami at this location. The purpose of this study was to analyze the existing huge potential energy in Sulawesi Sea subduction zone and to identify tsunami modeling likely to occur based on the potential energy of the region. The approach used in assessing the tsunami disaster was the calculation of the potential energy of an earthquake and tsunami modeling based on the potential energy. The method used in this research was the least squares method for the calculation of potential energy, and near-field tsunami modeling with the assistance of TUNAMI-N2 COD. The research finding has shown that the Sulawesi Sea subduction zone has potential energy of 1.35469?×?1023 erg, equivalent to an earthquake with a magnitude of 7.6 Mw. The tsunami modeling made shown the average wave propagation reaching ashore within 12.3 min with a height varying between 0.1 and >?3 m. The tsunami modeling also indicated that there are seven sub-districts in Buol District, Central Sulawesi, which is affected by a significant tsunami. 相似文献
20.
龚家方4号斜坡涌浪数值模拟分析 总被引：2，自引：0，他引：2
对于库区滑坡来说,不能只考虑滑坡体本身造成的灾害,还要考虑滑坡体引起的涌浪灾害,为了研究滑坡涌浪的传播、衰减规律,在Geo-wave软件的技术上,二次开发形成FAST软件。以三峡库区龚家方4号斜坡为研究对象,分别在175、156、145 m的库水位条件下,在长约23 km、宽约10.4 km的区域内进行涌浪数值模拟,获得涌浪传播模拟数据。经过模拟软件数据处理模块的计算分析,形成了分析涌浪传播规律的一系列图件。对不同水位下涌浪模拟的计算结果进行对比分析发现,随着库水位的下降,滑坡产生的最大涌浪值和在对岸的爬高值都有增长的趋势,但其对航道存在威胁的时间逐渐变短。模拟区各位置的最大波高空间分布形态具有中间内凹、两翼沿岸坡延伸的特征。涌浪传播的急剧衰减区基本分布在涌浪源附近1 km的范围内,涌浪源处的波高越大,单位距离内的涌浪下降高度也越大。由于涌浪在岸边有叠加、壅高现象,建议航道内船只经过地质灾害点附近时应沿江中心快速通行。 相似文献