Yo Fukutani

Kanto Gakuin University · College of Science and Engineering

The storm surges and high waves of Typhoon No. 15 in 2019 caused extensive damage, including inundation of reclaimed land and damage to parapets, along the coast of Yokohama City. In this study, we simply estimated the run-up speed of storm surge by tracking drifting objects in the video images captured by a camera installed at about 420 m from the...

Typhoon No. 15 in September 2019 caused significant storm surge damages to the Fukuura and Sachiura areas in Yokohama City, Kanagawa Prefecture. Based on the results of a questionnaire survey and a field survey, this study clarified a distribution of inundation depths on land and evaluated relationship between the inundation depths and damages to i...

Probabilistic tsunami inundation assessment ordinarily requires many inundation simulations that consider various uncertainties; thus, the computational cost is very high. In recent years, active research has been conducted to reduce the computational cost. In this study, the number of random tsunami sources was reduced to 20% of the original numbe...

In addition to the deterministic tsunami assumptions based on historical tsunamis, a probabilistic approach has been developed for hazard assessment by considering large number of tsunami scenarios. In coastal areas where tsunamis are feared to strike, if levees are raised only based on assumed tsunami height, raised levees may affect the daily lif...

Probabilistic tsunami inundation assessment ordinarily requires many inundation simulations that consider various uncertainties; thus, the computational cost is very high. In recent years, active research has been conducted to reduce the computational cost. In this study, we successfully reduced the number of random tsunami sources to 20% of the or...

This study presents a framework for rapid tsunami force predictions by the application of mode-decomposition-based surrogate modeling with 2D–3D coupled numerical simulations. A limited number of large-scale numerical analyses are performed for selection scenarios with variations in fault parameters to capture the distribution tendencies of the tar...

We propose the coRaL method (a method of incorporating Random phase model into Logic tree approach), which is a probabilistic tsunami hazard assessment method with a high objectivity by reforming the evaluation method of earthquake asperity model and the concept of aleatory uncertainty among the probabilistic methods using logic tree approach conve...

Numerous combinations of disaster reduction facilities should be taken into consideration to evaluate the damages of inundation due to probabilistic tsunami hazard. In this study, we implemented it and investigated how the tsunami inundation probability changes by using the levee fragility model. coRaL method was used to obtain the inundation depth...

This study presents an innovative probabilistic tsunami inundation assessment for an earthquake scenario to randomly generate tsunami inundation depth distributions by quantitatively evaluating the spatial correlation of tsunami inundation depths using singular value decomposition (SVD) derived from proper orthogonal decomposition and to evaluate t...

This study presents a framework for real-time tsunami force predictions by the application of mode decomposition based surrogate modelling with 2D-3D coupled numerical simulations. A limited number of large-scale numerical analyses are performed for a selection scenarios with variations in fault parameters to capture the distribution tendencies of...

In stochastic tsunami simulation, the numerical model is required to generate enough number of the sample earthquakes to cause the tsunami of the significant heights. The numerous results serves for the estimation of the occurrence probabilities against the target tsunami heights to design the dikes and to make the disaster reduction plan. Thus the...

In the evaluation of tsunami loads on various structures, the hydrostatic pressure (water depth coefficient), which is equivalent to three times of the design inundation depth, is basically applied, and its magnification is reduced according to the surrounding conditions. Although there have been many hydraulic model experiments and numerical analy...

It is necessary to evaluate aggregate damage probability to multiple buildings when performing probabilistic risk assessment for the buildings. The purpose of this study is to demonstrate a method of tsunami hazard and risk assessment for two buildings far away from each other, using copulas of tsunami hazards that consider the nonlinear spatial co...

It is necessary to consider simultaneous damage to multiple buildings when performing probabilistic risk assessment for a portfolio of buildings. In this study, we demonstrate tsunami risk assessment for two buildings using copulas of tsunami hazards that consider the nonlinear spatial correlation of tsunami wave heights. First, we simulated the wa...

Various methods such as a logic tree method and a random phase model have been proposed as a probabilistic tsunami hazard evaluation method. However, the calculation load is high because most of the methods require vast numbers of tsunami calculations. In this research, we aimed at evaluating probabilistic tsunami damage of a building using a metho...

Based on the definition of tsunami risk, we quantitatively evaluated the annual expected tsunami loss ratio (Tsunami Risk Index) and clarified the quantitative effects of epistemic uncertainties in tsunami hazard assessments on the tsunami risk of buildings by combining probabilistic information regarding tsunami inundation depths at target points...

This study presents a new framework of the probabilistic tsunami hazard evaluation which enables us to use numerical simulation effectively. The basic idea of the framework had been proposed for the reliability analysis of geostructures, and the key issue of the framework is use of the response surface which obtained from the results of numerical s...

In tsunami risk assessments, understanding the uncertainties involved in numerical simulations of tsunami wave heights and arrival times is important. However, few studies have been conducted to determine the effects of dynamic parameters (i.e., rupture velocity and rise time) in the simulation of tsunami wave heights and arrival times, although nu...

Since the 2011 Tohoku earthquake tsunami there have been multiple efforts to maintain the awareness of people in the affected areas, such as tsunami signs, memorials and evacuation drills. This chapter briefly introduces and summarizes the ongoing activities in this respect in Miyagi Prefecture. Tsunami signs are usually placed by both the Miyagi p...

We propose a quantitative evaluation method of overall tsunami risk that the entire facility group over a wide area holds. We considerably reduced the calculation cost for tsunami inundation depth by adopting the evaluation method using energy conservation law as compared with the evaluation method using nonlinear long wave equation. For financial...

The storm surge due to the December 2014 Nemuro cyclone was hindcast using the Delft-3D/SWAN combined hydrodynamic and wave model with Japan Meteorological Agency (JMA) Mesoscale Model (MSM) reanalysis data as the surface boundary condition. Wind and pressure fields near Nemuro from the JMA MSM reanalysis data set agree with data from AMEDAS weathe...

The 2011 Great East Japan tsunami severely damaged or destroyed most of the fishing ports and facilities along the Sanriku coast. Reconstruction is ongoing, and a relocation plan has already been enacted. Interviews with fishermen in three fishing villages were performed to obtain reports on current situations as well as opinions and problems. For...

The storm surge due to the December 2014 Nemuro cyclone was hindcast using the Delft-3D/SWAN combined hydrodynamic and wave model with Japan Meteorological Agency (JMA) Mesoscale Model (MSM) reanalysis data as the surface boundary condition. Wind and pressure fields near Nemuro from the JMA MSM reanalysis data set agree with data from AMEDAS weathe...

抄録 We performed a stochastic evaluation of tsunami inundation by using results of stochastic tsunami hazard assessment at the Soma port in the Tohoku coastal area. Eleven fault zones along the Japan trench were selected as earthquake faults generating tsunamis. The results show that estimated inundation area of return period about 1200 years had go...

We created a fault model with a Tohoku-type earthquake fault zone having a random slip distribution and performed stochastic tsunami hazard analysis using a logic tree. When the stochastic tsunami hazard analysis results and the Tohoku earthquake observation results were compared, the observation results of a GPS wave gauge off the southern Iwate c...

On January 15, 2013, heavy monsoon rains resulted in severe flooding in Jakarta city, West Java, Indonesia, which had resulted in 40 deaths, 45,000 refugees, and terrible economic damage. Jakarta city has experienced severe floods in 1996, 2002, 2007, 2013 and 2014. Such extreme flooding events might become more frequent in the future due to the im...

A large amount of buildings was damaged or destroyed by the 2011 Great East Japan tsunami. Numerous field surveys were conducted in order to collect the tsunami inundation extents and building damage data in the affected areas. Therefore, this event provides us with one of the most complete data set among tsunami events in history. In this study, f...