scholarly journals A numerical study of submarine–landslide–generated tsunami and its propagation in Majene, West Sulawesi

2021 ◽  
Vol 925 (1) ◽  
pp. 012035
Author(s):  
H Khoirunnisa ◽  
S Karima ◽  
G Gumbira ◽  
R A Rachman

Abstract On 14th January 2021, there was a devastating earthquake (Mw 6.2) hit Mamuju and Majene, West Sulawesi, Indonesia at 18.28 UTC. According to National Disaster Management Authority, this event causes 84 casualties and 279 houses were damaged. The Sulawesi Island is situated in a very complex tectonic region, there are several thrusts and faults along the area such as Majene Thrust, Palu-Karo Thrust, Matano Fault, and Tolo Thrust that can lead to tectonic activities. One of the largest earthquakes was a 7.9 Mw in 1997 generated from North Sulawesi Megathrust that caused a catastrophic tsunami. Moreover, there were 9 tsunami events in the Makassar Strait from the year 1800 to 1999. In this research, three different scenarios of the tsunami in Majene were applied to obtain the tsunami elevation. Makassar Strait could be potentially generated tsunami wave from submarine landslides due to its steep bathymetry that will impact the coastline at Sulawesi and Kalimantan, so it is necessary to model the tsunami propagation using submarine landslide as the tsunami generation. The volume of submarine landslide had been used in tsunami submarine landslide modelling as an input. Those are included the height, width and length of the submarine landslide volume. Furthermore, the domain bathymetry was obtained from National Bathymetry (BatNas) with spacing grid of 300 m × 300 m. The submarine landslide coordinate is also needed as a source of tsunami at 2.98°S and 118.94°E. The slide angle and slope angle are also inputted in this modelling with three experimental volumes, namely 1 km3, 0.8 km3, and 0.5 km3. This submarine landslide tsunami modelling used the Non-Hydrostatic WAVE Model (NHWAVE) method to obtain tsunami wave generation. The result from NHWAVE model will be used for initial elevation of tsunami wave propagation using the Fully Nonlinear Boussinesq wave model - Total Variation Diminishing (FUNWAVE - TVD) method. The highest initial tsunami elevation value at each observation point obtained from the NHWAVE model occurred at point 18 (the closest location to the earthquake source), which is around 0.4 –1.2 m. The FUNWAVE simulation result is the tsunami wave propagation for 180 minutes later. In the 180th minute, the tsunami wave was still propagating towards the north of Sulawesi Island to the east of Kalimantan Island.

Author(s):  
A. Yu. Belokon ◽  

This paper is devoted to computational modelling of tsunami wave propagation and runup to the shore for some points on the Russian, Turkish, Bulgarian and Ukrainian coasts of the Black Sea. The nonlinear long wave model was used to solve the problem of wave propagation from hydrodynamic tsunami sources, which can constitute the greatest potential danger for the studied coast areas. The hydrodynamic sources were set in the form of an elliptical elevation, the parameters of which were chosen according to the sea level response to an underwater earthquake of magnitude 7. All the sources were located in seismically active areas, where tsunamigenic earthquakes had already occurred, along the 1500 m isobath. Near each of the studied points in the area above 300 m depths, we calculated marigrams, i.e. time-series of sea level fluctuations caused by the passage of waves. Then, a one-dimensional problem of tsunami propagation and run-up on the coast was solved for each of the points under study, where the obtained marigrams were used as boundary conditions. Peculiarities of tsunami wave propagation have been shown depending on the bottom and land relief in the studied areas of the Black Sea. Estimates have been obtained of the sea level maximum rise and fall during surge and subsequent coastal drainage for the characteristic scales of relief irregularity at different points. For possible tsunamigenic earthquakes, the largest splashes may occur in the region of Yalta (2.15 m), Cide (1.9 m), Sevastopol (1.4 m), and Anapa (1.4 m). Tsunami propagation in the Feodosiya and Varna coastal areas is qualitatively similar, with maximum wave heights of 0.64 m and 0.46 m, respectively. The coastlines of Evpatoriya (0.33 m) and Odessa (0.26 m) are least affected by tsunami waves due to the extended shelf.


Author(s):  
K. Qu ◽  
G. Y. Lan ◽  
S. Kraatz ◽  
W. Y. Sun ◽  
B. Deng ◽  
...  

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.


Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1290 ◽  
Author(s):  
Jiajia Pan ◽  
Hung Tao Shen

A two-dimensional wave model coupled with ice dynamics is developed to evaluate ice effects on shallow water wave propagation on a beach and in a channel. The nonlinear Boussinesq equations with ice effects are derived and solved by the hybrid technique of the Godunov-type finite volume method and finite difference method with the third-order Runge–Kutta method for time integration. The shock capturing method enables the model to simulate complex flows over irregular topography. The model is capable of simulating wave propagations accurately, including non-hydrostatic water pressure and wave dispersions. The ice dynamic module utilizes a Lagrangian discrete parcel method, based on smoothed particle hydrodynamics. The Boussinesq wave model is validated with an analytical solution of water surface oscillation in a parabolic container, an analytical solitary wave propagation in a flat channel, and experimental data on tsunami wave propagations. The validated model is then applied to investigate the interaction between ice and tsunami wave propagation, in terms of ice attenuation on tsunami wave propagations over a beach, ice deposition on the beach driven by the tsunami wave, and ice jam formation and release in a coastal channel with the intrusion of the tsunami wave. The simulated results demonstrated the interactions between tsunami waves and surface ice, including the maximum run up, ice movement along the beach, and ice jamming in a channel.


Landslides ◽  
2021 ◽  
Author(s):  
Ramtin Sabeti ◽  
Mohammad Heidarzadeh

AbstractThe accurate prediction of landslide tsunami amplitudes has been a challenging task given large uncertainties associated with landslide parameters and often the lack of enough information of geological and rheological characteristics. In this context, physical modelling and empirical equations have been instrumental in developing landslide tsunami science and engineering. This study is focused on developing a new empirical equation for estimating the maximum initial landslide tsunami amplitude for solid-block submarine mass movements. We are motivated by the fact that the predictions made by existing equations were divided by a few orders of magnitude (10−1–104 m). Here, we restrict ourselves to three main landslide parameters while deriving the new predictive equation: initial submergence depth, landslide volume and slope angle. Both laboratory and field data are used to derive the new empirical equation. As existing laboratory data was not comprehensive, we conduct laboratory experiments to produce new data. By applying the genetic algorithm approach and considering non-dimensional parameters, we develop and examine 14 empirical equations for the non-dimensional form of the maximum initial tsunami amplitude. The normalized root mean square error (NRMSE) index between observations and calculations is used to choose the best equation. Our proposed empirical equation successfully reproduces both laboratory and field data. This equation can be used to provide a preliminary and rapid estimate of the potential hazards associated with submarine landslides using limited landslide parameters.


2014 ◽  
Vol 21 (5) ◽  
pp. 987-1005 ◽  
Author(s):  
W. Kristina ◽  
O. Bokhove ◽  
E. van Groesen

Abstract. An effective boundary condition (EBC) is introduced as a novel technique for predicting tsunami wave run-up along the coast, and offshore wave reflections. Numerical modeling of tsunami propagation in the coastal zone has been a daunting task, since high accuracy is needed to capture aspects of wave propagation in the shallower areas. For example, there are complicated interactions between incoming and reflected waves due to the bathymetry and intrinsically nonlinear phenomena of wave propagation. If a fixed wall boundary condition is used at a certain shallow depth contour, the reflection properties can be unrealistic. To alleviate this, we explore a so-called effective boundary condition, developed here in one spatial dimension. From the deep ocean to a seaward boundary, i.e., in the simulation area, we model wave propagation numerically over real bathymetry using either the linear dispersive variational Boussinesq or the shallow water equations. We measure the incoming wave at this seaward boundary, and model the wave dynamics towards the shoreline analytically, based on nonlinear shallow water theory over bathymetry with a constant slope. We calculate the run-up heights at the shore and the reflection caused by the slope. The reflected wave is then influxed back into the simulation area using the EBC. The coupling between the numerical and analytic dynamics in the two areas is handled using variational principles, which leads to (approximate) conservation of the overall energy in both areas. We verify our approach in a series of numerical test cases of increasing complexity, including a case akin to tsunami propagation to the coastline at Aceh, Sumatra, Indonesia.


2018 ◽  
Vol 477 (1) ◽  
pp. 293-301 ◽  
Author(s):  
Dominique Turmel ◽  
Jacques Locat ◽  
Jonathan Leblanc ◽  
Geneviève Cauchon-Voyer

AbstractOn the north shore of the St Lawrence Estuary (Québec, Canada), near the Betsiamites river delta, a large sub-aerial submarine landslide complex was mapped using multi-beam bathymetry and light detection and ranging (LiDAR) data. Previous analysis of this landslide complex revealed that, since 7250 cal years BP, at least four different landsliding events occurred to form the present morphology, in which over 2 km3 of material have been mobilized. The 7.25 cal ka BP landslide is of particular interest here: this landslide is entirely submarine and mobilized about 1.3 km3 of material, deposited over an area of 54 km2, which make this landslide the largest identified on the St Lawrence estuary seafloor. This landslide showed a runout distance of about 15 km. Landslide-generated tsunamis may be triggered by such a landslide, where a large volume of material is mobilized in a short time. Kinematic analysis of this landslide was previously performed, and here we use these analyses in order to perform tsunami wave generation and propagation modelling. It is shown in this analysis that, even if the mobilized volume is very high and there is a long runout, the tsunami generated is small with tsunami wave amplitudes of <1.5 m, except in the vicinity of the landslide. The highest tide elevation in this part of the St Lawrence Estuary is about 5.5 m, so the impact of such a tsunami wave may be limited.


Author(s):  
Alexandre Janin ◽  
Mathieu Rodriguez ◽  
Dimitris Sakellariou ◽  
Vasilis Lykousis ◽  
Christian Gorini

Abstract. The North Anatolian Fault in the northern Aegean Sea triggers frequent earthquakes of magnitude up to Mw ∼ 7. This seismicity can be a source of modest tsunamis for the surrounding coastlines with less than 50 cm height according to numerical modelling and analysis of tsunami deposits. However, other tsunami sources may be involved, like submarine landslides. We assess the severity of this potential hazard by performing numerical simulations of tsunami generation and propagation from a Holocene landslide (1.85 km3 in volume) identified off Thasos island. We use a model coupling the simulation of the submarine landslide, assimilated to a granular flow, to the propagation of the tsunami wave. The results of these simulations show that a tsunami wave of water height between 1.10 m and 1.65 m reaches the coastline at Alexandroupolis (58.000 inhabitants) one hour after the triggering of the landslide. In the same way, tsunamis waves of water height between 0.80 m and 2.00 m reach the coastline of the Athos peninsula 9 min after the triggering of the landslide. Landslide tsunamis should not be neglected as a potential source of tsunami in the area. Despite numerous earthquakes of Mw > 7 and strong detrital input (on the order of 30 cm ka−1), only a few Holocene landslides have been recognized so far, asking the question of the relationships between seismicity and landslide frequency in the area.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
A. Fornaciai ◽  
M. Favalli ◽  
L. Nannipieri

AbstractStromboli volcano (Aeolian Arc, Italy) experiences many mass failures along the Sciara del Fuoco (SdF) scar, which frequently trigger tsunamis of various sizes. In this work, we simulate tsunami waves generated by landslides occurring in the SdF through numerical simulations carried out in two steps: (i) the tsunami triggering, wave propagation and the effects on Stromboli are simulated using the 3D non-hydrostatic model NHWAVE; (ii) generated train waves are then input into the 2D Boussinesq model FUNWAVE-TVD to simulate wave propagation in the Southern Tyrrhenian Sea (STS). We simulated the following scenarios: (i) the tsunami runup, inland inundation and wave propagation at Stromboli triggered by submarine landslides with volumes of 6, 10, 15 and 20 × 106 m3 and subaerial landslides with volumes of 4, 6, 10 and 30 × 106 m3; (ii) tsunami propagation in the STS triggered by submarine landslides with volumes of 10 and 15 × 106 m3 and by subaerial landslides with volumes of 6 and 30 × 106 m3. We estimate that the damages of the last relevant tsunami at Stromboli, which occurred in 2002, could have been generated either by a subaqueous failure of about 15–20 × 106 m3 along the SdF or/and a subaerial failure of about 4–6 × 106 m3. The coasts most affected by this phenomenon are not necessarily located near the failure, because the bathymetry and topography can dramatically increase the waves heights locally. Tsunami waves are able to reach the first Stromboli populated beaches in just over 1 minute and the harbour in less than 7 minutes. After about 30 minutes the whole Aeolian Arc would be impacted by maximum tsunami waves. After 1 hour and 20 minutes, waves would encompass the whole STS arriving at Capri.


2014 ◽  
Vol 1 (1) ◽  
pp. 317-369
Author(s):  
W. Kristina ◽  
O. Bokhove ◽  
E. van Groesen

Abstract. An effective boundary condition (EBC) is introduced as a novel technique to predict tsunami wave run-up along the coast and offshore wave reflections. Numerical modeling of tsunami propagation at the coastal zone has been a daunting task since high accuracy is needed to capture aspects of wave propagation in the more shallow areas. For example, there are complicated interactions between incoming and reflected waves due to the bathymetry and intrinsically nonlinear phenomena of wave propagation. If a fixed wall boundary condition is used at a certain shallow depth contour, the reflection properties can be unrealistic. To alleviate this, we explore a so-called effective boundary condition, developed here in one spatial dimension. From the deep ocean to a seaward boundary, i.e., in the simulation area, we model wave propagation numerically over real bathymetry using either the linear dispersive variational Boussinesq or the shallow water equations. We measure the incoming wave at this seaward boundary, and model the wave dynamics towards the shoreline analytically, based on nonlinear shallow water theory over sloping bathymetry. We calculate the run-up heights at the shore and the reflection caused by the slope. The reflected wave is then influxed back into the simulation area using the EBC. The coupling between the numerical and analytic dynamics in the two areas is handled using variational principles, which leads to (approximate) conservation of the overall energy in both areas. We verify our approach in a series of numerical test cases of increasing complexity, including a case akin to tsunami propagation to the coastline at Aceh, Sumatra, Indonesia.


2021 ◽  
Author(s):  
Gugum Gumbira ◽  
Mardi Wibowo ◽  
Hanah Khoirunnisa ◽  
Shofia Karima ◽  
Widjo Kongko

Abstract Tsunami modelling of potential landslide-induced tsunami in Makassar Strait is carried out to quantify possible damage to the nearby cities. Two numerical models are used to represent the wave generation and propagation by using NHWAVE and FUNWAVE models, respectively. The simulations consist of a series of scenarios based on distinct size of the landslide volume. Four landslides with volume 5, 8, 70, and 200 km 3 are used as tsunami sources in the initiation stage. The sources are evenly distributed in the Strait addressing different landslide location. Maximum wave heights of 1.5 m are found in the area between Palu and Bangkir from case 1 and around Talok from case 2 simulations. The empirical run-up calculation of 7.5 m is estimated at the land for the presented wave height. The value significantly elevates the case 3 and 4 proportional to the volume values. The waves impact more than half of coastline with maximum value found in the Sulawesi side. Interestingly, wide and narrow shelf next to Kalimantan Island plays an important role in reducing the tsunami hazard level.


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