On the contribution of the horizontal sea-bed displacements into the tsunami generation process

DYNAMIC TSUNAMI GENERATION PROCESS OBSERVED IN THE 2003 TOKACHI-OKI, JAPAN, EARTHQUAKE

Advances in Geosciences - A 6-Volume Set - Volume 16: Atmospheric Science(AS) ◽

10.1142/9789812838148_0009 ◽

2010 ◽

pp. 159-168 ◽

Cited By ~ 3

Author(s):

TATSUO OHMACHI ◽

SHUSAKU INOUE

Keyword(s):

Generation Process ◽

Tsunami Generation

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A Numerical Study of Tsunami Generation by Horizontal Displacement of Sloping Seafloor

Journal of Earthquake and Tsunami ◽

10.1142/s1793431120500189 ◽

2020 ◽

Vol 14 (04) ◽

pp. 2050018 ◽

Cited By ~ 1

Author(s):

Chentong Hu ◽

Yifan Wu ◽

Chao An ◽

Hua Liu

Keyword(s):

Numerical Study ◽

Horizontal Displacement ◽

Vertical Displacement ◽

Horizontal Motion ◽

Generation Process ◽

Tsunami Generation ◽

Initial Water ◽

Horizontal Momentum ◽

The Difference ◽

Water Elevation

Tsunamis are generated primarily by the vertical displacement of the seafloor if the seafloor is flat. If the seafloor is slanted, the horizontal motion also contributes to the generation of tsunamis. A previous study proposed that such effects can be estimated by simply calculating the elevation of water due to the horizontal displacement of the slope. Two more studies later argued that the horizontal motion also results in horizontal momentum of the water, which amplifies the tsunami generation. In this study, we numerically simulate the tsunami generation process of flat and sloping seafloor. It is found that, for the flat seafloor, the initial water elevation equals the vertical seafloor displacement. For the sloping seafloor, the initial water elevation deviates from the vertical seafloor displacement, and the difference can be accurately evaluated by the horizontal seafloor displacement. Thus, the initial horizontal momentum of the water is negligible for tsunami generation.

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Dynamic Tsunami Generation Process by the 2003 Tokachi-Oki Earthquake

PROCEEDINGS OF COASTAL ENGINEERING JSCE ◽

10.2208/proce1989.55.336 ◽

2008 ◽

Vol 55 ◽

pp. 336-340

Author(s):

Tatsuo Ohmachi ◽

Shusaku Inoue ◽

Tetsuji Imai

Keyword(s):

Generation Process ◽

Tsunami Generation

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Time-dependent Tsunami Source Following the 2018 Anak Krakatau Volcano Eruption Inferred from Nearby Tsunami Recordings

10.21203/rs.3.rs-26757/v1 ◽

2020 ◽

Author(s):

Yifan Zhu ◽

Chao An ◽

Teng Wang ◽

Hua Liu

Keyword(s):

Source Region ◽

Time Dependent ◽

Tsunami Source ◽

Water Volume ◽

Generation Process ◽

Tsunami Generation ◽

Time Duration ◽

Initial Water ◽

Volcano Eruption ◽

Krakatau Volcano

Abstract The eruption of the Anak Krakatau volcano, Indonesia, on 22 December 2018 induced a destructive tsunami (the Sunda Strait tsunami), which was recorded by four nearby tidal gauges. In this study we invert the tsunami records and recover the tsunami generation process. Two tsunami sources are obtained, a static one of instant initial water elevation and a time-dependent one accounting for the continuous evolution of water height. The time-dependent results are found to reproduce the tsunami recordings more satisfactorily. The complete tsunami generation process lasts approximately 9 min and features a two-stage evolution with similar intensity. Each stage lasts about 3.5 min and elevates a water volume of about 0.15 km 3 . The time, duration and volume of the volcano eruption in general agree with seismic records and geomorphological interpretations. We also test different sizes of the potential source region, which lead to different maximum wave height in the source area, but all the results of time-dependent tsunami sources show the robust feature of two stages of wave generation. Our results imply a time-dependent and complex process of tsunami generation during the volcano eruption.

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Three-Dimensional Modeling of Tsunami Generation and Propagation under the Effect of Stochastic Seismic Fault Source Model in Linearized Shallow-Water Wave Theory

ISRN Applied Mathematics ◽

10.1155/2014/874230 ◽

2014 ◽

Vol 2014 ◽

pp. 1-27 ◽

Cited By ~ 3

Author(s):

Allam A. Allam ◽

M. A. Omar ◽

Khaled T. Ramadan

Keyword(s):

Shallow Water ◽

Water Depth ◽

Three Dimensional ◽

Source Model ◽

Generation Process ◽

Tsunami Generation ◽

Propagation Length ◽

Seismic Fault ◽

Amplitude Amplification ◽

Fault Source

Tsunami generation and propagation caused by stochastic seismic fault driven by two Gaussian white noises in the x- and y-directions are investigated. This model is used to study the tsunami amplitude amplification under the effect of the noise intensities, spreading uplift length and rise times of the three-dimensional stochastic fault source model. Tsunami waveforms within the frame of the linearized shallow-water theory for constant water depth are analyzed analytically by transform methods (Laplace in time and Fourier in space). The amplification of tsunami amplitudes builds up progressively as time increases during the generation process due to wave focusing while the maximum wave amplitude decreases with time during the propagation process due to the geometric spreading and also due to dispersion. The maximum amplitude amplification is proportional to the propagation length of the stochastic source model and inversely proportional to the water depth. The increase of the normalized noise intensities on the bottom topography leads to an increase in oscillations and amplitude in the free surface elevation. We derived and analyzed the mean and variance of the random tsunami waves as a function of the propagated uplift length, noise intensities, and the average depth of the ocean along the generation and propagation path.

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Tsunami generation by ocean floor rupture front propagation: Hamiltonian description

Natural Hazards and Earth System Science ◽

10.5194/nhess-9-217-2009 ◽

2009 ◽

Vol 9 (1) ◽

pp. 217-227 ◽

Cited By ~ 1

Author(s):

V. I. Pavlov ◽

J. Tromp ◽

E. P. Tito

Keyword(s):

Front Propagation ◽

Ocean Floor ◽

Far Field ◽

Generation Process ◽

Tsunami Generation ◽

Hamiltonian Method ◽

Hamiltonian Description ◽

Alternative Framework ◽

Analytical Expressions

Abstract. The Hamiltonian method is applied to the problem of tsunami generation caused by a propagating rupture front and deformation of the ocean floor. The method establishes an alternative framework for analyzing the tsunami generation process and produces analytical expressions for the power and directivity of tsunami radiation (in the far-field) for two illustrative cases, with constant and gradually varying speeds of rupture front propagation.

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