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The current prototype of a fully automatic earthquake tsunami hazard assessment system, “Tsunami Observer”, is described. The transition of the system to the active phase of operation occurs when information about a strong earthquake (Mw ≥ 6.0) is received. In the first stage, the vector field of coseismic displacements of the Earth’s crust is calculated by using the Okada formulas. In the calculations, use is made of data on the coordinates, the seismic moment, the focal mechanism, and the depth of the earthquake, as well as empirical patterns. In the second stage, the initial elevation of the water surface at the tsunami’s focus is determined with the vector field of coseismic displacements of the bottom and the distribution of ocean depths, and the earthquake’s potential energy is calculated. In the third stage, the intensity of the tsunami is estimated on the Soloviev–Imamura scale in accordance with the magnitude of the potential energy by using the empirical relationship that is obtained as a result of a statistical analysis of historical tsunami events. In the final stage, if the energy exceeds the critical value of 109 J, a numerical simulation of the tsunami is performed, which allows the determination of the predominant directions of wave energy propagation and estimation of the runup height on the nearest coast. In this work, data on the operation of the system over the last 3 years are presented.

Rapid and reliable tsunami forecasting for regions close to the epicenter of an undersea earthquake remains an unsolved problem. The only method of rapid tsunami hazard estimation used in Russia is the magnitude criterion. It leads to an unacceptably high percentage of false alarms. One promising new method is the modeling of the earthquake source based on the coseismic displacements recorded at coastal observation sites by Global Navigation Satellite Systems (GNSS). In this paper, we focus on the possibility of using this method for the magnitude 7–8 intraplate earthquakes, for which it is necessary to determine the rupture plane orientation. Based on numerical experiments, we obtained estimates of the accuracy and reliability of the earthquake parameters depending on the magnitude, number and relative positions of GNSS stations. We show that it is possible to determine all the main parameters of the source model of an M ≥ 7.4 earthquake based on the GNSS data, although the accuracy would not be very good. We conclude that it is advisable to use GNSS data in tsunami warning systems, at first in the testing mode.

Submarine earthquakes in South West Anatolia’s offshore region are a major threat to the coastal settlements therein. Many cities on Turkish and Greek territory suffered from earthquakes through historical time. The social and economic impact of these events have been documented in several historical earthquake catalogues. This article provides an analysis for the historical earthquakes from B.C. 2000 until the 18th century for the offshore region of SW Anatolia (Muğla Province). The summary consists of 17 earthquakes with intensities ranging from VII to X. A significant gap of earthquakes exists between the 6th and the 15th century (883 years). Available damage records concentrate on Rhodos and Kos island, with little information for the surrounding coastal region. Nevertheless, the historical and present day seismicity shows that the islands and coasts in SW Anatolia have experienced several destructive earthquakes between magnitudes of Mw 6 to 8. This fact should be taken into account in seismic hazard assessments and mitigation efforts for the area.

Detecting ocean-floor seismic activity is crucial for our understanding of the interior structure and dynamic behavior of the Earth. However, 70% of the planet’s surface is covered by water and seismometers coverage is limited to a handful of permanent ocean bottom stations. We show that existing telecommunication optical fiber cables can detect seismic events when combined with state-of-the-art frequency metrology techniques by using the fiber itself as the sensing element. We detected earthquakes over terrestrial and submarine links with length ranging from 75 to 535 km and a geographical distance from the earthquake's epicenter ranging from 25 to 18,500 km. Implementing a global seismic network for real-time detection of underwater earthquakes requires applying the proposed technique to the existing extensive submarine optical fiber network., peer-reviewed

The most acceptable method to estimate tsunami inundation caused by a submarine earthquake is by conducting a nonlinear tsunami simulation. However, this method has the disadvantages of a relatively high computational cost and the necessity for immediate warning announcements when a tsunami is imminent. In this study, to overcome this problem, we apply two machine learning models, a convolutional neural network and a multilayer perceptron, to estimate tsunami inundation in real time. We run multiple fault scenarios and store the result of the maximum tsunami amplitude in a low-resolution grid and the associated tsunami inundation in a high-resolution grid in the database. The convolutional neural network selects tsunami inundation in the high-resolution grid as the forecast based on pattern similarity between the input, which is the results of linear forward modeling in the low-resolution grid, and the precomputed patterns in the database. Slightly different from the convolutional neural network, instead of selecting the best-fit scenario in the database, the multilayer perceptron directly generates the inundation forecast based on knowledge acquired during the training process. We conduct an experiment using the hypothetical future Nankai megathrust earthquake with Atashika and Owase Bays in Japan as the study cases. The results show that our proposed methods are extremely fast (less than 1 s) and comparable with nonlinear forward modeling. Therefore, the proposed methods can be used as a deterministic model for real-time simulation.

The Tsunami Observer automatic system for assessment of earthquake tsunami hazard has been operating since January 25, 2018. In this report we analyze the results of the system over the past year and a half, comparison of the estimates made by the system and in situ observations data is performed. The time delay of issue of focal mechanism, which is critical to fast tsunami hazards assessment, is discussed.

The paper is devoted to the analysis of the features of the EWH parameter change over the geoid using satellite measurements of the GRACE space system. These local gravitational anomalies are studied depending on the geometrical characteristics of the focal zones of the strongest underwater earthquakes in the period 2003-2016. The statistical processing of satellite observations data using the histogram and maximum entropy methods was performed. Completed interpretation and obtained estimates showing differences and similarities in observational data, due to the peculiarities of the structure of the studied geomedia and the corresponding focal areas. The final result is a statistical description of the space of anomalies of the gravitational field of the Earth as a whole and features of local gravitational anomalies over the focal zones of underwater strong earthquakes in the period from 2003 to 2016.

A submarine earthquake that generates a tsunami sends a family of acoustic signals that carry information on the fault dynamics and geometry. These signals travel at the speed of sound in water, much greater than the phase speed of the gravity waves, and thus can act as early warning of tsunamis. To utilise this property in real-time, a semi-analytical inverse approach is employed assuming the fault is slender and the water depth is constant, allowing the calculation of some fault parameters analytically. However, the remaining parameters require a numerical evaluation, which increases the calculation time substantially. In order to overcome this difficulty, a probabilistic inverse model is proposed. The model analyses data at the envelope of a pressure signal, which reduces numerical complexities. More specifically, it selects multiple measurement points, in order to produce several sets of solutions within given ranges of the properties. The model is applied to real hydrophone recordings, where the fault geometry and dynamics are estimated near real-time on a standard PC. Some aspects of the model are general and can be used to estimate simplified geometry and dynamics of various signal sources from violent events in the ocean, such as impacting meteorites, submarine explosions, landslides and rogue waves.

The massive destruction and loss caused by the 2004 Sumatra–Andaman tsunami were attributed to the lack of knowledge on tsunami and low regional detection and communication systems for early warning in that region. This study aimed to identify locations at risk of impending tsunami from Andaman Sea for the safety of community and proper development planning at the coastal areas by providing an updated and revised inundation maps. The last study on this area was conducted several years ago which open the possibility to new findings. Generated by tsunami simulation models, the maps illustrate the extent and level of inundation to which the coastal community and infrastructure would be subjected. As a result of coastal changes and availability of better topographic data, the existing inundation maps for the coastal areas of northwest Peninsular Malaysia at risk to impending tsunami from the Andaman Sea are revised. This paper documented the computational setup leading to the generation of the revised inundation maps. The tsunami simulation model TUNA was used to simulate the generation, propagation, and subsequent run-up and inundation of tsunamis triggered by earthquakes of moment magnitudes (Mw) 8.5, 9.0, and 9.25 along the Sunda Trench. From the simulations, it was found that at Mw 9.25, Balik Pulau, Pulau Pinang would be subjected to inundation of as far as 3.47 km with 5.40-m-deep inundation at the highest section.

How the tsunami hazard affecting life in Palabuhanratu District is investigated in this paper. By considering this district as a tourist area that is visited by many tourists, the coastal activity is quite high compared to other areas. In the southern region of Java Island, or more precisely Pelabuhanratu, there is an active tectonic zone that can cause underwater earthquakes with a potential strength of up to 8.7 Mw. An underwater earthquake of this magnitude can cause a large tsunami potential, which will greatly affect or even paralyze community activities in coastal areas. This study is conducted to analyze the impact of a potential tsunami that could occur on community activities in the area. To achieve this, it is necessary to do tsunami modeling with numerical methods using the COMCOT v1.7 software on two scenarios. Then the results of the visualization of the inundation will be overlaid with land cover data and buildings data in Palabuhanratu District. The results of this study indicate that the tsunami immersion height in the first scenario modeling is much higher than the second scenario, which is more than 30 m. Meanwhile, for the second scenario, it reaches more than 4 m. The potential for this tsunami caused several losses to the residents, namely the residential area of 917.51 ha is submerged and 17,709 buildings affected in the first scenario, as well as the residential area of 260.54 ha is submerged and 2,779 buildings affected in the second scenario.

Earthquake-induced hydrodynamic pressure on the ocean floor is a key factor in evaluating the surface disturbance and dynamic response of the seabed under the action of a submarine earthqu...

We characterized the phase noise and instability of submarine optical fibers and estimate achievable performances of trans-oceanic fiber-based optical frequency transfer, in view of intercontinental atomic clock comparisons. We also show that the low noise of the submarine environment allows exploitation of long-haul telecom fibers as distributed sensors for underwater earthquakes.

The study is devoted to the analysis of the features of the EWH (Equivalent Water Height) parameter over the geoid using satellite measurements of the GRACE space system in seismically active areas of the strongest underwater earthquakes. Created archive of satellite data GRACE. Interpretation of the disturbed state of the geomedia using digital maps of the spatial distribution of the parameter EWH is performed.

Large underwater earthquakes (Mw>7) can transmit part of their energy to the surrounding ocean through large seafloor motions, generating tsunamis that propagate over long distances. The forcing effect of tsunami waves on the atmosphere generates internal gravity waves that, when they reach the upper atmosphere, produce ionospheric perturbations. These perturbations are frequently observed in the total electron content (TEC) measured by multifrequency Global Navigation Satellite Systems (GNSS) such as GPS, GLONASS, and, in the future, Galileo. This paper describes the first inversion of the variation in sea level derived from GPS TEC data. We used a least squares inversion through a normal‐mode summation modeling. This technique was applied to three tsunamis in far field associated to the 2012 Haida Gwaii, 2006 Kuril Islands, and 2011 Tohoku events and for Tohoku also in close field. With the exception of the Tohoku far‐field case, for which the tsunami reconstruction by the TEC inversion is less efficient due to the ionospheric noise background associated to geomagnetic storm, which occurred on the earthquake day, we show that the peak‐to‐peak amplitude of the sea level variation inverted by this method can be compared to the tsunami wave height measured by a DART buoy with an error of less than 20%. This demonstrates that the inversion of TEC data with a tsunami normal‐mode summation approach is able to estimate quite accurately the amplitude and waveform of the first tsunami arrival.

Tsunamigenic earthquakes trigger pressure waves in the ocean, given the weak compressibility of the sea water. For particular conditions, a resonant behavior of the water layer can occur, which influences the energy transfer from the sea-bed motion to the ocean. In this paper, the resonance conditions are explained and analyzed, focusing on the hydro-acoustic waves in the proximity of the earthquake area. A preliminary estimation of the generation parameters (sea-bed rising time, velocity) is given, by means of parametric numerical simulations for simplified conditions. The results confirm the importance of measuring, modeling, and interpreting such waves for tsunami early detection and warning.

A disastrous tsunami is generally known as the ocean water response to an offshore fault rupture as the consequence of a submarine earthquake. Such a physical understanding, however, cannot explain the generation of the 2018 Sulawesi earthquake induced Palu Bay tsunami. In this study, it is demonstrated that the sloshing effect dominates a tsunami event if it occurs in a semi-closed water body near the epicenter and the ground motion triggered by the earthquake is strong enough in the horizontal directions. The 2018 Palu Bay tsunami became disastrous since the sloshing effect played a significant role while landslides also contributed to the big runup at some particular locations. The present study is significant since sloshing is usually considered to play a minor role in amplifying a tsunami wave and has not been included in existing tsunami warning systems. Owing to such a limitation, the 2018 Palu Bay tsunami event was not correctly predicted at all. To prevent a future tragedy, an urgent update of the worldwide tsunami warning system in service may have to be performed to include an option for possible consideration of the sloshing effect.

Based on the data from the GPS receiving networks in Japan and America which have a high time resolution (2 min), two-dimensional (2D) distributions of the variations in the ionospheric total electron content (TEC) are constructed both close to and far from of the epicenter of the submarine earthquake of March 11, 2011 in Japan. Above the epicenter, a diverging multi-period disturbance appears after the main shock due to the acoustic gravity waves. Far from the epicenter, the wave trains associated with the tsunamigenic atmospheric internal gravity waves are revealed. These atmospheric waves significantly advance the arrival of the tsunami signal initially on the Hawaiian islands and then on the western coast of North America. The presence of the tsunami precursor in the form of atmospheric gravity waves is supported by the numerical calculations and by the analysis of the dispersion relation for the waves in the atmosphere. The detected ionospheric responses close and far from the epicenter can be used in the early tsunami warning systems.

Tsunami generation and propagation due to a randomly fluctuating of submarine earthquake modeled by vertical time-dependent of a stochastic bottom displacement are investigated. The increase in oscillations and amplitude in the free surface elevation are controlled by the noise intensity parameter of the stochastic bottom displacement. Evolution of kinetic and potential energy of the resulting waves by the stochastic bottom displacement is examined. Exchange between potential and kinetic energy was achieved in the propagation process. The dynamic ocean-bottom pressure during tsunami generation is investigated. As the vertical displacement of the stochastic bottom increases, the peak amplitude of the ocean-bottom pressure increases through the dynamic effect. Time series of the maximum tsunami wave amplitude, kinetic and potential energy, wave and ocean-bottom pressure gauges and the hydrodynamic force caused by the stochastic source model under the effect of the water depth of the ocean are investigated.

The results of calculating the characteristics of the pseudopositioning of two navigational receivers in Tuapse and 60 km north of Tuapse at the Goryachii Klyuch locality before and after a weak submarine earthquake are presented. The earthquake with the epicenter 2 km offshore of Tuapse occurred on September 8, 2010. The experiment was conducted with the satellite receivers recoding the signals of the GLONASS/GPS global navigational satellite systems (GNSS). The receivers pertain to the system of satellite monitoring and forecasting the natural and manmade hazards on the segment of the North Caucasian Tuapse–Adler railroad. The pseudopositioning calculations based on the first carrier frequency of a GLONASS/GPS GNSS are conducted by the original author’s technology for monitoring the ionosphere and geological motions. It is established that the errors of the pseudopositioning estimates increase by the time of the earthquake. The accompanying effects in the variations of the ionospheric electron density and in the state of the Earth’s magnetic field are considered. The obtained results complement the existing data on the dynamics of the precursors of the earthquakes.

The paper investigates on the hydro-acoustic waves propagation caused by the underwater earthquake, occurred on 6 February 2012, between the Negros and Cebu islands, in the Philippines. Hydro-acoustic waves are pressure waves that propagate at the sound celerity in water. These waves can be triggered by the sudden vertical sea-bed movement, due to underwater earthquakes. The results of three dimensional numerical simulations, which solve the wave equation in a weakly compressible sea water domain are presented. The hydro-acoustic signal is compared to an underwater acoustic signal recorded during the event by a scuba diver, who was about 12 km far from the earthquake epicenter.

The study is devoted to the analysis of the features of the change in the parameter EWH (Equivalent Water Height) over the geoid from the satellite measurements of the GRACE space system in seismically active areas of the strongest underwater earthquakes. The GRACE satellite data archive was created. An interpretation of the disturbed state of the geomedium using digital maps of the spatial distribution of the parameter EWH is performed.

The frequency of tsunamis in Indonesia is smaller than other natural disasters. But its destructive power is quite large. Although this disaster has a low probability of occurring. The losses caused by these disaster equaled and even exceeded frequent disasters such as floods and landslides. More than 85% of tsunamis in Indonesia were caused by underwater earthquakes. Thus, mitigation efforts are needed to minimize the impact of the tsunami disaster. The source of the tsunami wave was generated on the Makassar Strait Thrust North Fault. In this study, tsunami was modelled by using Delft3D software. The model approach uses the principle of momentum and continuity. The area of the model was divided into 2 grids. The wave reached the bay mouth in 10 minutes and arrived at the coast of the study area in 20 minutes. The highest peak of water level on the coast occurred in the second wave with an amplitude of 2.45 m and a wave height of 5.19 m. The inundation map was compared to the recorded data from the 2018 tsunami. It was found that there is no significant difference between the two although the tsunami generation were different.

The Makran subduction located at the northwest of the Indian ocean, at the Oman Sea mouth has been and is the source of massive tsunamis that threatens the coasts of Iran, Pakistan, India and Oman. The initial tsunami wave produced by the magnitude and focal depth of Makran submarine earthquake in 1945 is determined based on the Okada algorithm. 3D propagation of the generated mega wave in the Indian Ocean and Oman Sea is simulated by adopting OpenFOAM open source CFD software, in its global sense and verified vs. the available data. The wave characteristics are extracted from the global model at the mouth of Chabahar Bay are inserted as the input in a regional model which consist of precise geometry and bathymetry of the bay and finer mesh size. The wave run-up is predicted at the main ports at the Indian Ocean and Oman Sea coastline. The obtained results are implemented to assess the tsunami risk zone of Teess beach town, at Chabahar Bay coastline. The advanced procedure applied in this research consists of the accurate production of the original tsunami and three stages of global and regional 3D and local 2D propagation simulation, that provides reliable results in more accurate estimation of wave run up height and tsunami risk zone, for practical engineering applications.

An uplift of the ocean bottom caused by a submarine earthquake can trigger acoustic-gravity waves that travel at near the speed of sound in water and thus may act as early tsunami precursors. We study the spatiotemporal evolution of the pressure field induced by acoustic-gravity modes during submarine earthquakes, analytically. We show that these modes may all induce comparable temporal variations in pressure at different water depths in regions far from the epicenter, though the pressure field depends on the presence of a leading acoustic-gravity wave mode. Practically, this can assist in the implementation of an early tsunami detection system by identifying the pressure and frequency ranges of measurement equipment and appropriate installation locations.

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.

Indian Ocean Tsunami 2004 informed on the amplitude of marine inundations that can occur in the eastern coasts of India. Geological signatures of such high-energy marine wave events are inferred from the older sedimentary records using chaotic deposits and/or boulder deposits with a word of caution to link them with tsunami, as similar records could be seen linked with super typhoon like Haiyan occurred in Pacific Ocean on 7 November 2013 (Kennedy et al. in Coast Eng J 58(1):1640004, 2016). We present here the geological evidences of high-energy marine wave events from the coastline of Gujarat in western India and suggest that these are tsunamigenic because the Arabian Sea has not experienced super cyclones (known as typhoon in Pacific region) at least since 100 years (Dube et al. in Appl Math Model 9:289–294, 1985), and local bathymetric conditions are not favourable to cause strong coupling of infragravity waves and sea swells that happened at eastern Samar island, the Philippines (Roeber and Bricker in Nat Commun 6:1–18, 2015. doi: 10.1038/ncomms8854 ; Shimozono et al. in J Geophys Res Oceans 120(6):4463–4486, 2015). In the region between Mundra and Bhadreshwar of the Kachchh coast, a tsunami event inferred by the presence of sand layer sandwiched between mud layers occurred around 1.3 ± 0.3 ka, based on optically simulated luminescence (OSL) dating method. Further, in the coastline between Madhavpur and Chorwad, large boulders as imbricates, scattered and embedded blocks in a sandy matrix are seen. OSL date for this event was 6.6 ± 0.7 ka. Occurrence of a tsunamite at Ratiya, north of Madhavpur yielded an OSL date of 35.4 ± 4.3 ka. Geological evidences further suggested that the possible energy source of sand layers was a tsunami event in the Strait of Hormoz. And, the boulders of Ratiya–Madhavpur–Chorwad segment were most possibly driven by waves from the submarine earthquake and/or landslides in the southern Owen Ridge.

Tsunamis induced by underwater earthquakes are theoretically analyzed by applying the linear potential theory. Special attention is placed on the initial state of tsunami. For instantaneous seabed deformations, analytical wave solutions induced by three fundamental seabed deformations at initial stage are derived rather than integral expressions in past studies. These analytical solutions constitute a fundamental base for analyzing waves generated by arbitrary seabed displacement with the help of Fourier analysis. Tsunamis induced by non-instantaneous seabed deformation are analyzed as well. For the sake of examining the contributions of all wave components involved in the tsunami waveform, the amplitude density is proposed to examine the effects of deformation width, water depth, harmonic mode and rising time on waveforms. Results show that a larger ratio of water depth to deformation width results in a greater difference between initial waveform and seabed deformation, and the effect of the rising time is significant in deeper-water configuration. For cosine and sine seabed liftings, the effects of higher harmonic modes might be ignored.

As devastating and unpredictable tsunamis generated by underwater earthquakes are occurring more frequently, the need for tsunami disaster prevention measures is rapidly increasing. In this study, tsunami heights were estimated, and the best-fit distribution was examined through a combination of numerical analyses and statistical methods. A numerical model was employed to estimate the tsunami heights, and the parameters were estimated using the method of L-moments applied to the estimated tsunami heights. The best-fit distribution was determined by applying the estimated parameters to the L-moment ratio diagram. The study areas were the Imwon Port and the Sadong Port located in the eastern part of the Korean Peninsula. The tsunami height distribution was represented by a log-normal distribution for the Imwon Port, whereas the distribution was represented by a generalized Pareto distribution for the Sadong Port. The study indicates that the distribution most commonly suggested by previous studies, i.e., the log-normal distribution, is not always accurate. Therefore, when performing statistical analysis on tsunami heights, the assumption of a log-normal distribution should be considered carefully.

The data provided by ten DONET deep-sea observatories, that on March 11, 2011, registered the Great East Japan Earthquake and tsunami, were used for investigation of the relationship between variations of the ocean bottom pressure and three-component accelerograms. Methods of cross-spectral analysis revealed the existence of a frequency range of “forced oscillations,” within which pressure variations are proportional to the vertical component of the acceleration. This proportionality is manifested by the magnitude-squared coherence (MSC) being close to unity and a phase lag (PL) practically equal to zero. The spectral analysis method showed the proportionality coefficient to be equal the mass of a water column of unit area at the installation point of the observatory or, approximately, to the product of the water density and the ocean depth. The observed boundaries of the frequency range of “forced oscillations” are revealed to correspond to the theoretical frequency values confining the manifestation of surface gravity and acoustic waves in pressure variations near the ocean bottom. The hypothesis is put forward that the small deviations of MSC from unity and of PL from zero observed by a number of stations within the range of “forced oscillations” are due to the contribution of horizontal movements of nearby submarine slopes. A theoretical analysis has been performed of the problem of forced oscillations of a water layer in a basin of varying depth. A formula is obtained that relates pressure variations at the ocean bottom to acceleration components of the bottom motion and the bottom slope. The pressure in the region of forced oscillations is shown to decrease exponentially with the distance from the moving segment of the ocean bed, so pressure variations, originating from movements of the bottom, are registered effectively by a gauge at the ocean bottom only within a radius less than 1–2 ocean depths. A cross-spectral analysis of pressure variations and of three-component accelerograms confirmed the hypothesis concerning the contribution of horizontal movements of nearby submarine slopes to pressure variations.

Sources of tsunamis are non-uniform and commonly uncorrelated and very difficult to predict. The best ideal way to appear their aspects is through heterogeneous or stochastic source models which are more realistic. The effect of random fluctuation of submarine earthquake modeled by vertical time-dependent displacement of a stochastic source model is investigated on the tsunami generation and propagation waves. The noise intensity parameter controls the increase of the stochastic bottom amplitude which results in increasing the oscillations and amplitude in the free surface elevation which provides an additional contribution to tsunami waves. The L2 norm of the free surface elevation, the displaced water volume and the potential energy are examined. These quantitative information about predicting tsunami risk are useful for risk managers who decide to issue warnings and evacuation orders. The horizontal average velocity flow rates of the tsunami wave are investigated. The average velocity flow rates can provide valuable information about the stochastic bottom topography by the distinctive velocity oscillations. Flow velocity is of importance in risk assessment and hazard mitigation which may provide a clear signal of tsunami flows. Time series of the flow velocities and wave gauges under the effect the water depth of the ocean are investigated.

The 26 December 2004 Tsunami generated by the submarine earthquake in Andaman Sea with the magnitude of 9.2 Richter scale triggered the worst destruction, widespread inundation and extensive damage in terms of life and property along the Tamil Nadu coast and Andaman Nicobar Group of Islands. The shoreline features like dunes, vegetation and steepness of beaches played vital role in attenuating the impact of Tsunami from destruction. While the low-level Marina beach experienced minimum inundation, the coast between Adyar and Cooum was inundated heavily. As the present generation of India was not aware of Tsunami, the emergency plan and preparedness were zero and so the loss of human life was huge. In this article, the authors describe the Tsunami occurred in India on 26 December 2004 and its impacts on morphology. The appropriate Emergency Preparedness plan and the Disaster Management Plan in case of reoccurrence of such natural disaster are discussed.

In this study, a forecast system for tsunami early warning in Taiwan is constructed by integrating the source model that generates the initial tsunami elevation based on earthquake fault parameters, the propagation model that calculates the offshore sea surface quickly by precomputed reciprocal Green's functions, and the nearshore module that interpolates the inundated distance to the shoreline based on precomputed inundation simulations. This system is integrated and executed by a Matlab graphic utility interface (GUI). In this interface system, the rupture parameters such as epicenter location, focal depth, and fault angles are used to compute the initial tsunami wave elevation. These rupture parameters can be retrieved from the website of the U.S. Geological Survey or the F-net Broadband Seismograph Network of Japan for the most updated earthquake parameters. For the highly nonlinear coastal inundation, a bell-shaped wave is used to generate the inundation map, which is then transformed into a Google Earth format and demonstrated via this geographic information system. This system has been applied in both 2010 Chilean Tsunami and 2011 Great Eastern Japan Tsunami. In both cases, the result has order-of-magnitude accuracy; thus, this system provides a quick first estimation for an early warning of a tsunami when a submarine earthquake occurs.