Analysis of Spatio-Temporal Tsunami Source Models for Reproducing Tsunami Inundation Features

We report results of field surveys and numerical modeling of the tsunami generated by the Anak Krakatau volcano eruption on 22 December 2018. We conducted two sets of field surveys of the coastal areas destroyed by the Anak Krakatau tsunami in 26-30 December 2018 and 4-10 January 2020. Field surveys provided information about the maximum tsunami height as well as the most damaged area. The maximum tsunami height was up to 13 m. Most locations registered a wave height of 3-4 m. Tsunami inundation was limited to approximately 100 m. For modeling, we considered 12 source models and conducted numerical modeling. The scenarios have source dimensions of 1.5&#8211;4&#8239;km and initial tsunami amplitudes of 10&#8211;200&#8239;m. By comparing observed and simulated waveforms, we constrained the tsunami source dimension and initial amplitude in the ranges of 1.5&#8211;2.5&#8239;km and 100&#8211;150&#8239;m, respectively. The best source model involves potential energy of 7.14&#8239;&#215;&#8239;1013&#8211;1.05&#8239;&#215;&#8239;1014&#8239;J which is equivalent to an earthquake of magnitude 6.0&#8211;6.1.

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Multilayer modelling of waves generated by explosive submarine volcanism

10.5194/nhess-2021-109 ◽

2021 ◽

Author(s):

Matthew W. Hayward ◽

Colin N. Whittaker ◽

Emily M. Lane ◽

William Power ◽

Stéphane Popinet ◽

...

Keyword(s):

Underwater Explosion ◽

Theoretical Models ◽

Mono Lake ◽

Tsunami Source ◽

Computationally Efficient ◽

Relative Significance ◽

Submarine Volcanism ◽

Wave Characteristics ◽

Wide Range ◽

Source Models

Abstract. Theoretical source models of underwater explosions are often applied in studying tsunami hazards associated with submarine volcanism; however, their use in numerical codes based on the shallow water equations can neglect the significant dispersion of the generated wavefield. A non-hydrostatic multilayer method is validated against a laboratory-scale experiment of wave generation from instantaneous disturbances and at field-scale submarine explosions at Mono Lake, California, utilising the relevant theoretical models. The numerical method accurately reproduces the range of observed wave characteristics for positive disturbances and suggests a previously unreported relationship of extended initial troughs for negative disturbances at low dispersivity and high nonlinearity parameters. Satisfactory amplitudes and phase velocities within the initial wave group are found using underwater explosion models at Mono Lake. The scheme is then applied to modelling tsunamis generated by volcanic explosions at Lake Taupō, New Zealand, for a magnitude range representing ejecta volumes between 0.04–0.4 km3. Waves reach all shores within 15 minutes with maximum incident crest amplitudes around 4 m at shores near the source. This work shows that the multilayer scheme used is computationally efficient and able to capture a wide range of wave characteristics, including dispersive effects, which is necessary when investigating submarine explosions. This research therefore provides the foundation for future studies involving a rigorous probabilistic hazard assessment to quantify the risks and relative significance of this tsunami source mechanism.

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UNCERTAINTY ASSESSMENT OF TSUNAMI HEIGHT FOR FUTURE NANKAI-TONANKAI EARTHQUAKES USING STOCHASTIC TSUNAMI SOURCE MODELS

Journal of Japan Society of Civil Engineers Ser B2 (Coastal Engineering) ◽

10.2208/kaigan.77.2_i_181 ◽

2021 ◽

Vol 77 (2) ◽

pp. I_181-I_186

Author(s):

Takuya MIYASHITA ◽

Kazuki KURATA ◽

Tomohiro YASUDA ◽

Nobuhito MORI ◽

Tomoya SHIMURA

Keyword(s):

Uncertainty Assessment ◽

Tsunami Source ◽

Tsunami Height ◽

Source Models

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On the landslide tsunami uncertainty and hazard

Landslides ◽

10.1007/s10346-020-01429-z ◽

2020 ◽

Vol 17 (10) ◽

pp. 2301-2315 ◽

Cited By ~ 1

Author(s):

Finn Løvholt ◽

Sylfest Glimsdal ◽

Carl B. Harbitz

Keyword(s):

Hazard Analysis ◽

Tsunami Hazard ◽

Tsunami Source ◽

Probabilistic Framework ◽

Tsunami Inundation ◽

Event Trees ◽

To Come ◽

Probabilistic Tsunami Hazard Analysis ◽

Landslide Tsunami ◽

Prognostic Modelling

Abstract Landslides are the second most frequent tsunami source worldwide. However, their complex and diverse nature of origin combined with their infrequent event records make prognostic modelling challenging. In this paper, we present a probabilistic framework for analysing uncertainties emerging from the landslide source process. This probabilistic framework employs event trees and is used to conduct tsunami uncertainty analysis as well as probabilistic tsunami hazard analysis (PTHA). An example study is presented for the Lyngen fjord in Norway. This application uses a mix of empirical landslide data combined with expert judgement to come up with probability maps for tsunami inundation. Based on this study, it is concluded that the present landslide tsunami hazard analysis is largely driven by epistemic uncertainties. These epistemic uncertainties can be incorporated in the probabilistic framework. Conducting a literature analysis, we further show examples of how landslide and tsunami data can be used to better constrain landslide uncertainties, combined with statistical and numerical analysis methods. We discuss how these methods, combined with the probabilistic framework, can be used to improve landslide tsunami hazard analysis in the future.

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A STUDY ON THE ANALYSIS OF THE INUNDATION OF ISHIKAWA COAST BY TSUNAMI SOURCE MODELS

Journal of Japan Society of Civil Engineers Ser A1 (Structural Engineering & Earthquake Engineering (SE/EE)) ◽

10.2208/jscejseee.69.i_1021 ◽

2013 ◽

Vol 69 (4) ◽

pp. I_1021-I_1033

Author(s):

Hidekazu ARAI ◽

Katsushi ASO ◽

Masakatsu MIYAJIMA ◽

Toshiharu KITA ◽

Naoki NOMURA

Keyword(s):

Tsunami Source ◽

Source Models

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Probabilistic Tsunami Hazard Analysis: High Performance Computing for Massive Scale Monte Carlo type Inundation Simulations

10.5194/egusphere-egu2020-8041 ◽

2020 ◽

Author(s):

Steven J. Gibbons ◽

Manuel J. Castro Díaz ◽

Sylfest Glimsdal ◽

Carl Bonnevie Harbitz ◽

Maria Concetta Lorenzino ◽

...

Keyword(s):

High Performance Computing ◽

High Performance ◽

Hazard Analysis ◽

Tsunami Hazard ◽

Propagation Model ◽

Tsunami Source ◽

Tsunami Inundation ◽

Center Of Excellence ◽

Probabilistic Tsunami Hazard Analysis ◽

Performance Computing

Probabilistic Tsunami Hazard Analysis (PTHA) is an approach to quantifying the likelihood of exceeding a specified metric of tsunami inundation at a given location within a given time interval. It provides scientific guidance for decision making regarding coastal engineering and evacuation planning. PTHA requires a discretization of many potential tsunami source scenarios and an evaluation of the probability of each scenario. The classical approach of PTHA has been the quantification of the tsunami hazard offshore, while estimates of the inundation at a given coastal site have been limited to a few scenarios. PTHA, with an adequate discretization of source scenarios, combined with high-resolution inundation modelling, has been out of reach with existing models and computing capabilities with tens to hundreds of thousands of moderately intensive numerical simulations being required. In recent years, more efficient GPU-based High Performance Computing (HPC) facilities, together with efficient GPU-optimized shallow water type models for simulating tsunami inundation, have made a regional and local long-term hazard assessment feasible. PTHA is one of the so-called Pilot Demonstrators of the EC-funded ChEESE project (Center of Excellence for Exascale Computing in the Solid Earth) where a workflow has been developed with three main stages: source specification and discretization, efficient numerical inundation simulation for each scenario using the HySEA numerical tsunami propagation model, and hazard aggregation. HySEA calculates tsunami offshore propagation and inundation using a system of telescopic topo-bathymetric grids. In this presentation, we illustrate the workflows of the PTHA as implemented for HPC applications, including preliminary simulations carried out on intermediate scale GPU clusters. Finally, we delineate how planned upscaling to exascale applications can significantly increase the accuracy of local tsunami hazard analysis.This work is partially funded by the European Union&#8217;s Horizon 2020 Research and Innovation Program under grant agreement No 823844 (ChEESE Center of Excellence, www.cheese-coe.eu).

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Review: Source Models of the 2011 Tohoku Earthquake and Long-Term Forecast of Large Earthquakes

Journal of Disaster Research ◽

10.20965/jdr.2014.p0272 ◽

2014 ◽

Vol 9 (3) ◽

pp. 272-280 ◽

Cited By ~ 12

Author(s):

Kenji Satake ◽

◽

Yushiro Fujii ◽

Keyword(s):

Tohoku Earthquake ◽

2011 Tohoku Earthquake ◽

Tsunami Source ◽

The 2011 Tohoku Earthquake ◽

Term Forecast ◽

Trench Axis ◽

Source Models ◽

Plate Coupling ◽

Large Earthquakes

Numerous source models of the 2011 Tohoku earthquake have been proposed based on seismic, geodetic and tsunami data. Common features include a seismic moment of ∼ 4×1022 Nm, a duration of up to ∼ 160 s, and the largest slip of about 50 m east of the epicenter. Exact locations of this largest slip differ with the model, but all show considerable slip near the trench axis where plate coupling was considered to be weak and also at deeper part where M∼7 earthquakes repeatedly occurred at average 37-year intervals. The long-term forecast of large earthquakes made by the Earthquake Research Committee was based on earthquakes occurring in the last few centuries and did not consider such a giant earthquake. Among the several issues remaining unsolved is the tsunami source model. Coastal tsunami height distribution requires a tsunami source delayed by a few minutes and extending north of the epicenter, but seismic data do not indicate such a delayed rupture and there is no clear evidence of additional sources such as submarine landslides along the trench axis. Long-term forecast of giant earthquakes must incorporate non-characteristic models such as earthquake occurrence supercycles, assessments of maximum earthquake size independent of past data, and plate coupling based on marine geodetic data. To assess ground shaking and tsunami in presumed M∼9 earthquakes, characterization and scaling relation fromglobal earthquakes must be used.

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Numerical Simulation of Tsunami Run-Up and Inundation for the 2011 Tōhuku-Oki Tsunami: A Parametric Analysis for Tsunami Run-Up and Wave Height

Volume 8A: Ocean Engineering ◽

10.1115/omae2014-23138 ◽

2014 ◽

Author(s):

Debashis Basu ◽

Robert Sewell ◽

Kaushik Das ◽

Ron Janetzke ◽

Biswajit Dasgupta ◽

...

Keyword(s):

Wave Propagation ◽

Wave Height ◽

Seismic Waves ◽

Source Model ◽

Tsunami Source ◽

Computational Framework ◽

Wave Amplification ◽

Source Models ◽

Run Up ◽

Tsunami Run Up

This paper presents computational results for predicting earthquake-generated tsunami from a developed integrated computational framework. The computational framework encompasses the entire spectrum of modeling the earthquake-generated tsunami source, open-sea wave propagation, and wave run-up including inundation and on-shore effects. The present work develops a simplified source model based on pertinent local geologic and tectonic processes, observed seismic data (i.e., data obtained by inversion of seismic waves from seismographic measurements), and geodetic data (i.e., directly measured seafloor and land deformations). These source models estimated configurations of seafloor deformation used as initial waveforms in tsunami simulations. Together with sufficiently accurate and resolved bathymetric and topographic data, they provided the inputs needed to numerically simulate tsunami wave propagation, inundation and coastal impact. The present work systematically analyzes the effect of the tsunami source model on predicted tsunami behavior and the associated variability for the 2011 Tōhuku-Oki tsunami. Simulations were carried out for the 2011 Tōhuku -Oki Tsunami that took place on March 11, 2011, from an MW 9.1 earthquake. The numerical simulations were performed using the fully nonlinear Boussinesq hydrodynamics code, FUNWAVE-TVD (distributed by the University of Delaware). In addition, a sensitivity analysis was also carried out to study the effect of earthquake magnitude on the predicted wave height. The effect of coastal structure on the wave amplification at the shore is also studied. Simulated tsunami results for wave heights are compared to the available observational data from GPS (Global Positioning System) at the central Miyagi location.

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