The tsunami energy radiation directivity on the example of the 1994, 2006 and 2007 events

2021 ◽  
Author(s):  
Anastasia Ivanova
Keyword(s):  
Continental Slope ◽  
Wave Energy ◽  
Energy Flow ◽  
Tsunami Wave ◽  
Source Zone ◽  
Tsunami Source ◽  
Bottom Relief ◽  
Edge Waves ◽  
Tsunami Energy ◽  
Kuril Ridge

<p>Determining the tsunami source danger is currently one of the most urgent tasks. The vast majority of recorded tsunamis are of seismic origin. Part of the energy released during an earthquake passes into the energy of the initial tsunami source. The tsunami excitation efficiency depends on a number of factors: the depth of the sea above the source and its location relative to the coast and continental slope; the shape and area of residual post-seismic bottom displacements, as well as the bottom relief directly in the zone of the seismic source; inhomogeneities of the ocean floor relief along the path of tsunami propagation (for estimating wave heights in the zone farthest from the source); time inhomogeneities of tsunami wave radiation from the source zone; non-isotropy of the tsunami radiation spectrum.</p><p>To study the tsunami source efficiency, we considered three tsunamis in the Kuril ridge region: the Shikotan tsunami of 1994, and two Simushir tsunamis of 2006 and 2007. The choice of events was largely determined by the close geographical location – all of them belong to the Kuril-Kamchatka subduction zone. Also, these events are well studied, and there is quite a large amount of data on tsunami measurements onshore and in the deep ocean. At the same time, all three sources differ in the mechanisms of the seismic focus and location relative to the coast and the continental slope.</p><p>We analyzed the tsunami wave field for three events near the Russian Pacific coast. Tsunami energy flow calculations show that frontal energy flow is mainly directed to the southeast. The flux magnitude decreases with distance from the source as a result of geometric divergence and scattering. At longer distances, the effect of refraction becomes more significant – the flow is divided into separate rays due to the focusing on the irregular bottom relief.</p><p>The radiation patterns of each source that also were created show the part of wave energy that penetrated the Sea of Okhotsk through the Kuril Straits. It is easy to indicate the effect of the capture of tsunami waves by the shelf and the formation of edge waves that carry the wave energy away from the source area along the Kuril Ridge shelf. For 2006 and 2007 events a relatively small part of the wave energy went into the captured waves, but for 1994 the initial sea surface displacement area was in the shelf zone and a significant part of the energy was transferred to the captured edge waves, radiated mainly in the northeast direction.</p>

scholarly journals The Tsunami Wave Energy

2020 ◽  
Vol 18 (4) ◽  
pp. 39-53
Author(s):  
Andrey G. Marchuk
Keyword(s):  
Wave Energy ◽  
Water Surface ◽  
Tsunami Wave ◽  
Opposite Sign ◽  
Surface Displacement ◽  
Tsunami Source ◽  
Energy Radiation ◽  
Long Wave ◽  
Axis Length ◽  
Radiation Directivity

The basic formulae for calculating the moving long wave energy were derived and presented. The problems related to the energy counting in the course of numerical modeling of tsunami wave generation and propagation. Through a number of computational experiments, the wave energy radiation directivity of tsunami generated by an ellipsoidal source with a various axis length ratio was studied. The wave energy radiation directivity of the dipole tsunami source consisting of two ellipsoidal sources with opposite sign of the water surface displacement is considered.

scholarly journals Resonance phenomena at the long wave run-up on the coast

2013 ◽  
Vol 1 (2) ◽  
pp. 561-582
Author(s):  
A. Ezersky ◽  
D. Tiguercha ◽  
E. Pelinovsky
Keyword(s):  
Particle Velocity ◽  
Tsunami Wave ◽  
Earthquake Magnitude ◽  
Tsunami Source ◽  
Bottom Relief ◽  
Shallow Water Theory ◽  
Resonance Effects ◽  
Long Wave ◽  
Run Up ◽  
Linear Shallow Water Theory

Abstract. Run-up of long wave on a beach consisting of three pieces of constant but different slopes is studied. Linear shallow-water theory is used for incoming impulse evolution and non-linear corrections are obtained for the run-up stage. It is demonstrated that bottom profile influences the run-up characteristics and can lead to the resonance effects: increasing of wave height, particle velocity, and number of oscillations. Simple parameterization of tsunami source through an earthquake magnitude is used to calculate the run-up height versus earthquake magnitude. It is shown that resonance effects lead to the sufficient increasing of run-up heights for weakest earthquakes and tsunami wave does not break on chosen bottom relief if the earthquake magnitude does not exceed 7.8.

scholarly journals Resonance phenomena at the long wave run-up on the coast

2013 ◽  
Vol 13 (11) ◽  
pp. 2745-2752 ◽  
Author(s):  
A. Ezersky ◽  
D. Tiguercha ◽  
E. Pelinovsky
Keyword(s):  
Particle Velocity ◽  
Tsunami Wave ◽  
Earthquake Magnitude ◽  
Tsunami Source ◽  
Bottom Relief ◽  
Shallow Water Theory ◽  
Resonance Effects ◽  
Long Wave ◽  
Run Up ◽  
Linear Shallow Water Theory

Abstract. Run-up of long waves on a beach consisting of three pieces of constant but different slopes is studied. Linear shallow-water theory is used for incoming impulse evolution, and nonlinear corrections are obtained for the run-up stage. It is demonstrated that bottom profile influences the run-up characteristics and can lead to resonance effects: increase of wave height, particle velocity, and number of oscillations. Simple parameterization of tsunami source through an earthquake magnitude is used to calculate the run-up height versus earthquake magnitude. It is shown that resonance effects lead to the sufficient increase of run-up heights for the weakest earthquakes, and a tsunami wave does not break on chosen bottom relief if the earthquake magnitude does not exceed 7.8.

Numerical Study on Wave Attenuation of Tsunami-Like Wave by Emergent Rigid Vegetation

2021 ◽  
pp. 1-28
Author(s):  
K. Qu ◽  
G. Y. Lan ◽  
S. Kraatz ◽  
W. Y. Sun ◽  
B. Deng ◽  
...  
Keyword(s):  
Solitary Waves ◽  
Wave Energy ◽  
Wave Attenuation ◽  
Tsunami Wave ◽  
Numerical Study ◽  
Wave Model ◽  
Indian Ocean Tsunami ◽  
Vegetation Density ◽  
Rigid Vegetation ◽  
Total Wave

The extreme surges and waves generated in tsunamis can cause devastating damages to coastal infrastructures and threaten the intactness of coastal communities. After the 2004 Indian Ocean tsunami, extensive physical experiments and numerical simulations have been conducted to understand the wave attenuation of tsunami waves due to coastal forests. Nearly all prior works used solitary waves as the tsunami wave model, but the spatial-temporal scales of realistic tsunamis differ drastically from that of solitary waves in both wave period and wavelength. More recent work has questioned the applicability of solitary waves and been looking towards more realistic tsunami wave models. Therefore, aiming to achieve more realistic and accurate results, this study will use a parameterized tsunami-like wave based on wave observations during the 2011 Japan tsunami to study the wave attenuation of a tsunami wave by emergent rigid vegetation. This study uses a high-resolution numerical wave tank based on the non-hydrostatic wave model (NHWAVE). This work examines effects of prominent factors, such as wave height, water depth, vegetation density and width, on the wave attenuation efficiency of emergent rigid vegetation. Results indicate that the vegetation patch can dissipate a considerable amount of the total wave energy of the tsunami-like wave. However, the tsunami-like wave has a higher total wave energy, but also a lower wave energy dissipation rate. Results show that using a solitary instead of a tsunami-like wave profile can overestimate the wave attenuation efficiency of the coastal forest.

Distributed Damping of Tsunamis

2015 ◽  
Author(s):  
Mohammadreza Javanmardi ◽  
M. Reza Alam
Keyword(s):  
Shallow Water ◽  
Solitary Waves ◽  
Wave Breaking ◽  
Tsunami Wave ◽  
Coastal Communities ◽  
New Method ◽  
Major Threat ◽  
Tsunami Energy

Tsunamis are a major threat to coastal communities. One of the ways to avoid tsunami disasters is to use breakwaters to attenuate the incident tsunami energy. The incident tsunami energy is expected to be dissipated by induced wave breaking in the shallow water over the structure peak. In this paper, a new method to attenuate the tsunami energy is described and investigated. This new concept dissipates tsunami energy by implementing small barriers into the water before the tsunami reaches the shore. The interaction of tsunami-like solitary waves with new submerged barriers has been investigated and their performance was compared with that of conventional breakwaters. We found that the new structure can be used as a tsunami wave attenuator.

Engineering lessons from the 28 September 2018 Indonesian tsunami: debris loading

2020 ◽  
Vol 47 (1) ◽  
pp. 1-12 ◽  
Author(s):  
J. Stolle ◽  
C. Krautwald ◽  
I. Robertson ◽  
H. Achiari ◽  
T. Mikami ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Local Community ◽  
Field Survey ◽  
Tsunami Wave ◽  
Concrete Structures ◽  
Tsunami Source ◽  
Reinforced Concrete Structures ◽  
Research Gaps ◽  
Survey Team ◽  
Source Mechanisms

A field survey team went to Palu City, Indonesia in the aftermath of the September 28th, 2018 earthquake and tsunami to investigate its effects on local infrastructure and buildings. The study focused on the coast of Palu Bay, where a tsunami wave between approximately 2 and 7 m high impacted the local community as a result of several complex tsunami source mechanisms. The following study outlines the results, focused on loading caused by debris entrained within the inundating flow. Damage to timber buildings along the coast was widespread, though reinforced concrete structures for the most part survived, providing valuable insights into the type of debris loads and their effects on structures. The results of this survey are placed within the context of Canadian tsunami engineering challenges and are compared to the recently-released ASCE 7 Chapter 6 – Tsunami Loads and Effects, detailing potential research gaps and needs.

Focused tsunami waves

2007 ◽  
Vol 463 (2087) ◽  
pp. 3055-3071 ◽  
Author(s):  
M.V Berry
Keyword(s):  
Tsunami Wave ◽  
Diffraction Theory ◽  
Initial Disturbance ◽  
Spatial Extent ◽  
Large Parameter ◽  
Tsunami Waves ◽  
Wave Elevation ◽  
Cusp Points ◽  
Tsunami Energy

Shallower regions in the oceans can act as lenses, focusing the energy of tsunamis, typically onto cusp points where two caustic lines meet. Diffraction theory enables calculation of the profile of a tsunami wave propagating through a cusp. The wave elevation depends on position, time and two main parameters M and B : the large parameter M is the distance of the cusp from the lens, divided by the local wavelength of the tsunami without focusing, and B quantifies the spatial extent of the initial disturbance. Focusing amplifies the wave by a factor A proportional to M 1/4 and can potentially multiply the tsunami energy (proportional to A 2 ) 10-fold over a transverse range of tens of kilometres.

scholarly journals A numerical study of tsunami wave impact and run-up on coastal cliffs using a CIP-based model

2017 ◽  
Vol 17 (5) ◽  
pp. 641-655 ◽  
Author(s):  
Xizeng Zhao ◽  
Yong Chen ◽  
Zhenhua Huang ◽  
Zijun Hu ◽  
Yangyang Gao
Keyword(s):  
Incident Wave ◽  
Tsunami Wave ◽  
Critical Value ◽  
Tsunami Source ◽  
Solid Boundary ◽  
Wave Impact ◽  
Submarine Slope ◽  
Coastal Cliffs ◽  
Run Up ◽  
The Impact

Abstract. There is a general lack of understanding of tsunami wave interaction with complex geographies, especially the process of inundation. Numerical simulations are performed to understand the effects of several factors on tsunami wave impact and run-up in the presence of gentle submarine slopes and coastal cliffs, using an in-house code, a constrained interpolation profile (CIP)-based model. The model employs a high-order finite difference method, the CIP method, as the flow solver; utilizes a VOF-type method, the tangent of hyperbola for interface capturing/slope weighting (THINC/SW) scheme, to capture the free surface; and treats the solid boundary by an immersed boundary method. A series of incident waves are arranged to interact with varying coastal geographies. Numerical results are compared with experimental data and good agreement is obtained. The influences of gentle submarine slope, coastal cliff and incident wave height are discussed. It is found that the tsunami amplification factor varying with incident wave is affected by gradient of cliff slope, and the critical value is about 45°. The run-up on a toe-erosion cliff is smaller than that on a normal cliff. The run-up is also related to the length of a gentle submarine slope with a critical value of about 2.292 m in the present model for most cases. The impact pressure on the cliff is extremely large and concentrated, and the backflow effect is non-negligible. Results of our work are highly precise and helpful in inverting tsunami source and forecasting disaster.

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