Numerical Simulation of Tsunami Inundation in Urban Areas

The population and property in urban areas facing waterfronts is rapidly increasing together with the probability that a huge tsunami will occur on the Pacific Rim. The huge potential damage reflects the need to develop a highly accurate simulation model for tsunami inundation to help mitigate tsunami effects. We developed a simulation model to estimate the inundation depth and speed of tsunamis in urban areas. The model was applied to calculate the vari- ation of inundation areas in a model city facing Tokyo Bay. Experiments of tsunami inundation in the model city on a 1/50 scale was carried out for validation of the numerical model.

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PHYSICAL AND NUMERICAL MODELING FOR DRIFT OBJECTS DUE TO TSUNAMI INUNDATION IN COASTAL URBAN AREA

Coastal Engineering Proceedings ◽

10.9753/icce.v36v.currents.13 ◽

2020 ◽

pp. 13

Author(s):

Yu Chida ◽

Nobuhito Mori ◽

Nobuki Fukui ◽

Tomohiro Yasuda ◽

Takashi Yamamoto ◽

...

Keyword(s):

Urban Area ◽

Urban Areas ◽

Large Scale ◽

Tohoku Earthquake ◽

Fire Spread ◽

Tsunami Inundation ◽

Inundation Depth ◽

The Pacific ◽

Laboratory Flume ◽

Series Of Experiments

Off the Pacific coast of Tohoku Earthquake and Tsunami, many ships, containers, cars, and wooden debris of collapsed houses were drifted by a huge tsunami. Their drift objects prevented the rapid elimination of obstacles and debris on land and sea. In addition, in areas where tsunami-fire occurred, accumulated wooden debris caused the large-scale fire spread. Generally, when assuming tsunami damages in urban areas, the inundation depth and arrival time of tsunami are mostly used. In order to enhance the tsunami damage assumptions in urban areas, to understand the characteristic of tsunami flow and the behavior of drift objects in urban areas is also important. However, it is very difficult to measure the state of actual tsunami flow and the behavior of drift objects by tsunami flow. This study aims to understand the characteristics of drift objects behavior in an urban area through a series of experiments in a laboratory flume. This study also validates numerical simulation model by comparing with the experimental results.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/09KWpiVSbmU

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NUMERICAL SIMULATION OF 1964 TSUNAMI ACROSS THE PACIFIC OCEAN

Coastal Engineering Proceedings ◽

10.9753/icce.v20.5 ◽

1986 ◽

Vol 1 (20) ◽

pp. 5

Author(s):

Michael H. Chen

Keyword(s):

Numerical Simulation ◽

Boundary Condition ◽

Numerical Model ◽

Pacific Ocean ◽

Arrival Time ◽

Two Dimensional ◽

Open Sea ◽

The Pacific ◽

The Pacific Ocean

A two dimensional numerical longwave model using an appropriate open sea boundary condition has been developed. The use of the open-sea boundary condition makes it possible to simulate longwave propagation using a smaller region without covering the entire ocean. The numerical model is used to predict the arrival time of tsunamis resulting from the 1964 Alaskan earthquake at various stations with reasonable success.

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Development of a numerical simulation model for suction rate using CADMAS-SURF

MATEC Web of Conferences ◽

10.1051/matecconf/201819202063 ◽

2018 ◽

Vol 192 ◽

pp. 02063

Author(s):

Kornvisith Silarom ◽

Yoshimichi Yamamoto ◽

Syota Yoshizawa ◽

Nunthawath Charusrojthanadech

Keyword(s):

Numerical Simulation ◽

Numerical Model ◽

Simulation Model ◽

Flow Velocity ◽

Pore Water Pressure ◽

Water Pressure ◽

Wave Pressure ◽

Elapsed Time ◽

Shallow Area ◽

Suction Rate

There are many cases where a coastal dike or a seawall constructed on a very shallow area was broken by a wave of a smaller height than the designed height. In many of these cases, the reason of the destruction was the suction phenomena. This phenomenon happens when waves reaches the front of the dike or the seawall, the wave pressure scours the front soil of the structure until it reaches the lowest edge of the structure followed by sucking of backfilling material of the structure. In this research, the authors proposed the numerical model which can calculate the suction rate with elapsed time by applying the pore water pressure and the flow velocity inside a dike or a seawall using “CADMAS-SURF”. The authors proposed three coefficients for improving the calculated pressure from CADMAS-SURF. The reliability of the model was confirmed by reproducing the suction phenomena in Hirono Coast of Japan.

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Reduction of tsunami inundation by coastal forests in Yogyakarta, Indonesia: a numerical study

Natural Hazards and Earth System Science ◽

10.5194/nhess-12-85-2012 ◽

2012 ◽

Vol 12 (1) ◽

pp. 85-95 ◽

Cited By ~ 8

Author(s):

W. Ohira ◽

K. Honda ◽

K. Harada

Keyword(s):

Numerical Model ◽

Numerical Study ◽

Exponential Model ◽

Coastal Areas ◽

Coastal Forest ◽

Coastal Forests ◽

Tsunami Inundation ◽

Inundation Depth ◽

Damping Effects ◽

The Impact

Abstract. Coastal forests are known to protect coastal areas from environmental degradation. In this paper, we examined another important role of coastal forests – to mitigate tsunami devastations to coastal areas. Using a two-dimensional numerical model (Harada and Imamura model, 2005), we evaluated the damping effects of a coastal forest to resist tsunami inundation in Yogyakarta, Indonesia. In the simulations, we set up a two-km long control forest with a representative topography of the study site and experimented its damping performance sensitivity under various width configurations, e.g. 20, 40, 60, 80, 100 and 200 m. The initial tsunami wave was set such that the inundation depth at the front edge of the forest would not exceed 4 m (tree fragility limit). The forest variables such as species, density, DBH, height and canopy size were determined from a typical forest of the site (Casuarina plantation, 4 trees/100 m2, Diameter at Breast Height = 0.20 m). The results showed that coastal forest with 100 m width reduced inundation flux, depth and area by 17.6, 7.0 and 5.7%, respectively. Exponential models were found to describe the relationships between forest width and tsunami inundation transmission. An additional experiment was performed using actual topography and a forest plantation plan with 100 m width for 2.46 km2. In this experiment, the results showed that the plan would reduce inundation flux by 10.1%, while the exponential model estimated it to be 10.6%, close to the numerical model results. It suggests that statistical models of forest width and damping effects are useful tools for plantation planning, as it allows for quicker evaluation of the impact of coastal forest without simulation modeling that requires a lot of data, time and computing power.

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Numerical Simulation of Urban Inundation Processes and Their Hydraulic Quantities – Tsunami Analysis Hackathon Theme 1 –

Journal of Disaster Research ◽

10.20965/jdr.2021.p0978 ◽

2021 ◽

Vol 16 (7) ◽

pp. 978-993

Author(s):

Tomohiro Yasuda ◽

Kentaro Imai ◽

Yoshinori Shigihara ◽

Taro Arikawa ◽

Toshitaka Baba ◽

...

Keyword(s):

Numerical Model ◽

Urban Areas ◽

Necessary Conditions ◽

Computational Cost ◽

Scale Model ◽

Research Groups ◽

High Reproducibility ◽

Tsunami Inundation ◽

Topographic Data ◽

Physical Experiments

The detailed understanding of tsunami hazard risk using numerical simulations requires a numerical model that can accurately predict tsunami inundation phenomena on land. In such models, the structural effects are indirectly considered using the variation of bottom roughness as a proxy for the differences in building densities. Only a few studies have conducted intermodel tests to investigate tsunami inundation in complex coastal urban cities. During the tsunami analysis hackathon held in September 2020, eight research groups met to have a detailed discussion on the current urban inundation problems. In this study, we conducted an intermodel comparison of the numerical tsunami models, using the data from physical experiments that were performed on a detailed urban model. Our objective was to investigate the necessary conditions of an accurate numerical model based that can ensure high reproducibility and practicality. It was confirmed that the accuracy of topographic data is an important parameter for tsunami inundation simulations in complex urban areas. Based on the computational cost and accuracy, we suggest that a resolution of 1 cm of topographic data is a sufficient condition for tsunami inundation simulations on 1/250 scale model.

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A pipe network simulation model with dynamic transition between free surface and pressurized flow

Drinking Water Engineering and Science Discussions ◽

10.5194/dwesd-7-27-2014 ◽

2014 ◽

Vol 7 (1) ◽

pp. 27-57

Author(s):

J. Fernández-Pato ◽

P. García-Navarro

Keyword(s):

Numerical Simulation ◽

Numerical Model ◽

Simulation Model ◽

Water Pressure ◽

Laboratory Data ◽

Finite Volume Methods ◽

Analytic Solutions ◽

Pipe Networks ◽

Network Simulation Model ◽

Supercritical Flows

Abstract. Water flow numerical simulation in urban pipe systems is one of the topics that shows the need for surface flows and pressurized flows in steady and transient situations. The governing equations for both flow types are different and this must be taken into account in order to get a complete numerical model for solving transients. A numerical simulation model is developed in this work, capable of solving pipe networks mainly unpressurized, with isolated peaks of pressurization. For this purpose, a reformulation of the mathematical model through the Preissmann slot method is proposed. By means of this technique, a reasonable estimation of the water pressure is calculated in cases of pressurization. The numerical model is based on the first order Roe's scheme, in the frame of finite volume methods. It is adapted to abrupt transient situations, with subcritial and supercritical flows. The validation has been done by means of several cases with analytic solutions or empirical laboratory data. It has also been applied to some more complex and realistic cases, like junctions or pipe networks.

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DEVELOPMENT OF TSUNAMI INUNDATION EVALUATION METHOD CONSIDERING DAMAGE LEVEL OF SEAWALL

Coastal Engineering Proceedings ◽

10.9753/icce.v36.currents.77 ◽

2018 ◽

pp. 77

Author(s):

Katsumi Seki ◽

Taro Arikawa ◽

Kenichiro Shimosako ◽

Tomohiro Takagawa ◽

Yu Chida

Keyword(s):

Numerical Simulation ◽

Monte Carlo ◽

Evaluation Method ◽

Numerical Models ◽

Destruction Process ◽

Tsunami Inundation ◽

Damage Level ◽

Inundation Area ◽

Inundation Depth ◽

Subduction Zone Earthquake

Against the huge tsunami with the subduction-zone earthquake, structures such as breakwater and seawall are constructed. The expected effects of these structures are to reduce the inundation depth and inundation area. In other words, if we estimate tsunami inundation using numerical simulation accurately, it is necessary to reflect the situation of these structures in the numerical models. However in the present technology, it is difficult to predict while to estimate and reflect the destruction process by earthquake and tsunami attack. In this study, we assume that the damage level of structures are uncertain phenomenon and we develop that evaluated the tsunami inundation stochastically using Monte Carlo method.

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