Estimation of Expected Loss by Storm Surges Along Tokyo Bay Coast

2019 ◽  
Author(s):  
Rikito Hisamatsu ◽  
Sooyoul Kim ◽  
Shigeru Tabeta
Keyword(s):  
Storm Surge ◽  
Storm Surges ◽  
Assessment Method ◽  
Insurance Premium ◽  
Tokyo Bay ◽  
Heavy Rainfall Event ◽  
Exceedance Probability ◽  
Insurance Company ◽  
Risk Modeling ◽  
Expected Loss

Abstract In Japan, the fundamental disaster management plan was modified after a heavy rainfall event in 2015. According to the updated plan, the transfer of flood disaster risk to non-life insurance is promoted by the Japanese government. Thus, the importance of flood risk modeling for the insurance industry has increased. Winds are expected to become even stronger, resulting in higher storm surges, when the central pressure of the typhoon is intensified. Furthermore, it is possible for an insurance system to experience peak risk when such damage occurs simultaneously. Hence, refining the assessment method of storm surge risk is very important. An insurance company to which storm surge risk is transferred needs to assess not only the infrequent risks, for managing the risk of the company, but also the expected value of the estimated loss, for evaluating the insurance premium. However, only a few studies have assessed storm surges by stochastic approaches. In this study, storm surge losses along the coast of Tokyo Bay are predicted using the output of a stochastic typhoon model for 10,000 years. Storm surge losses due to 600 typhoons potentially causing storm surge damage for 10,000 years are calculated. Exceedance probability curves (EP curves) of estimated storm surge loss for each asset are created. Expected loss and the loss of representative return periods are evaluated based on these EP curves. We successfully determined the expected loss with a small calculation load.

scholarly journals APPLICABILITY OF THE VERTICAL TELESCOPIC BREAKWATER USING THE PAST TYPHOON IN TOKYO BAY

2020 ◽  
pp. 35
Author(s):  
Yako Harada ◽  
Yukihisa Matsumoto ◽  
Kazuho Morishita ◽  
Nobuyuki Oonishi ◽  
Kazuyoshi Kihara ◽  
...  
Keyword(s):  
Climate Change ◽  
Storm Surge ◽  
Storm Surges ◽  
Numerical Calculations ◽  
Numerical Analyses ◽  
Tokyo Bay ◽  
Worst Case ◽  
Sea Levels ◽  
Long Period ◽  
The Past

The vertical telescopic breakwater(VTB), which is a new breakwater that permits the navigation of ships, remain at the bottom of the sea during calm and rise to the surface during tsunamis or storm surges. Kawai et al. (2017) and Arikawa et al. (2019) found that it is effective not only for swell waves, but also for long-period waves simulating tsunamis and storm surges by previous experiments and numerical analyses. However, there have been few studies on the performance of VTB by numerical calculations in actual ports using actual typhoons. In addition, sea levels and changes in characteristics of typhoon due to climate change are predicted to occur; hence, we are concerned about the damage in all quarters caused by storm surge inundation, especially at Tokyo. Therefore, in this study, we used hypothetical typhoons under worst-case scenarios and quantitatively evaluated the protection performance of VTB against hypothetical typhoons with different aperture rates of VTB in Tokyo Bay by the numerical simulation.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/qof5ixKqIiA

scholarly journals RISK ASSESSMENT OF AGGREGATE LOSS BY STORM SURGE INUNDATION IN ISE AND MIKAWA BAY

2018 ◽  
pp. 35
Author(s):  
Shota Hirai ◽  
Tomohiro Yasuda
Keyword(s):  
Risk Assessment ◽  
Storm Surge ◽  
Storm Surges ◽  
Insurance Contract ◽  
The Other ◽  
Insurance Company ◽  
Aichi Prefecture ◽  
Other Hand ◽  
Aggregate Loss

In the event of disaster, the risk of disaster are intertwined, and there is an occurrence possibility of simultaneous damage in multiple areas. Nationwide companies have more risks of simultaneous damage in multiple areas by one disaster. For example, factories in Osaka and in Nagoya, can be damaged by one typhoon. In this case, company will need more money when damage happened and better to make special insurance contract, e.g. Catastrophe bond. On the other hand, insurance company has to assess amount of insurance payout because to pay it for contracted companies quickly. Insurance company may have difficulty to estimate total amount since there are few researches assessing aggregate loss caused by coastal disasters. This research proposes a procedure of assessment of aggregate loss by storm surges in Ise and Mikawa Bay located in Aichi prefecture, Japan.

scholarly journals ON THE EFFECT OF CONFIGURATIONS OF THE COAST ON THE STORM SURGES IN THE ISE BAY

2011 ◽  
Vol 1 (7) ◽  
pp. 58
Author(s):  
Kiyoshi Tanaka ◽  
Akira Murota
Keyword(s):  
Storm Surge ◽  
Storm Surges ◽  
Tokyo Bay ◽  
Wind Drift ◽  
Long Wave ◽  
Water Rise ◽  
Predominant Factor ◽  
Topographical Effect ◽  
Wind Blow ◽  
Sea Coast

Wind drift is generally considered as the predominant factor of the storm surge along the sea coast. Authors noticed the fact that the duration of the wind blow of any direction is not long even at a big typhoon, while the storm surges more than 2 m are sometimes observed in the interiors of Osaka-, Ise-, and Tokyo-bay, and they have studied on another factor which might cause such water rise. A hump of water caused by a low atomospheric pressure transmits in the manner of a long wave and is deformed under the topographical effect when it comes into a bay. Authors are intending to show that the build-up of water due to topographical effect is sometimes larger than that occurring by wind drift. In this paper, the calculation was carried on neglecting the effect of wind drift and its result was compared with the observed value.

Downfall of Tokyo due to Devastating Compound Disaster

2011 ◽  
Vol 6 (2) ◽  
pp. 176-184 ◽  
Author(s):  
Yoshiaki Kawata ◽  
Keyword(s):  
Global Warming ◽  
Sea Level ◽  
Storm Surge ◽  
Storm Surges ◽  
Difficult Problem ◽  
Tokyo Bay ◽  
Edo Period ◽  
River Flooding ◽  
Compound Disaster

Compound disasters are defined as double- or triplepunch disasters. As such, they cause more serious cumulative damage than individual disasters occurring independently. The independent occurrence of Tokyo metropolitan inland earthquakes is expected to kill 11,000 and cause ¥112 trillion in damage. An earthquake in Tokyo would also destroy river levees, coastal dikes, and disaster measure facilities such as water gates and locks due to liquefaction. Following such a earthquake, river flooding by the Tone and Arakawa rivers or storm surge overflow around Tokyo bay could easily occur along with strong typhoons. An Edo period (1603-1868) compound disaster involved the 1855 Ansei Edo earthquake and the 1856 Ansei Edo storm surge. With global warming progressively worsening, huge floods and storm surges are increasingly likely to occur independently. The risk that they will occur as part of a compound disaster is also increasing. Catastrophic disasters are characterized by being super-wide in area damage, compound in combining disasters, and prolonged in recovery. With the vast sea-level or low areas in Tokyo, long-term submergence due to inundation will be unavoidable. The most difficult problem, however, will be how to evacuate over 1 million people.

Storm Surge Estimation Along Tokyo Bay Based on a Simple Stochastic Approach

2018 ◽  
Author(s):  
Rikito Hisamatsu ◽  
Sooyoul Kim ◽  
Shigeru Tabeta
Keyword(s):  
Numerical Model ◽  
Storm Surge ◽  
Return Period ◽  
Empirical Formula ◽  
Stochastic Analysis ◽  
Storm Surges ◽  
Stochastic Approach ◽  
Insurance Companies ◽  
Tokyo Bay ◽  
Risk Transfer

In recent years, refinement of stochastic storm surge estimation is essential for risk management in insurance industries because the Japanese government promotes flood risk transfer to insurance companies. Insurance systems may reach peak risk when storm surge damage occurs; however, there are only a few studies on the stochastic analysis of storm surges. This paper presents the stochastic evaluation of storm surges in Tokyo Bay. First, storm surges are assessed using two methods of an empirical formula and a numerical model. Then, the return period of storm surges is stochastically evaluated. It is found that an empirical formula underestimates the surge level in comparison to the numerical model. Based on the results of numerical model, the return period of a storm surge is proposed in Tokyo Bay.

scholarly journals Identifying the non-exceedance probability of extreme storm surges as a component of natural-disaster management using tidal-gauge data from Typhoon Maemi in South Korea

2020 ◽  
Author(s):  
Sang-Guk Yum ◽  
Hsi-Hsien Wei ◽  
Sung-Hwan Jang
Keyword(s):  
South Korea ◽  
Storm Surge ◽  
Probability Model ◽  
Storm Surges ◽  
Distribution Model ◽  
Exceedance Probability ◽  
Probability Models ◽  
Distribution Models ◽  
Sea Levels ◽  
Rising Sea Levels

Abstract. Global warming, one of the most serious aspects of climate change, can be expected to cause rising sea levels. These, in turn, have been linked to unprecedentedly large typhoons that can cause flooding of low-lying land, coastal invasion, seawater flows into rivers and groundwater, rising river levels, and aberrant tides. To prevent loss of life and property damage caused by typhoons, it is crucial to accurately estimate storm surge related risk. This study therefore develops a statistical model for estimating probability model, based on surge data pertaining to Typhoon Maemi, which struck South Korea in 2003. Specifically, estimation of non-exceedance probability models of the typhoon-related storm surge was achieved via clustered separated peaks-over-threshold simulation, while various distribution models were fitted to the empirical data for investigating the risk of storm surge height. The result of this process found that the result of Weibull distribution was better than other distribution model for Typhoon Maemi's peak total water level.

scholarly journals Estimation of the non-exceedance probability of extreme storm surges in South Korea using tidal-gauge data

2021 ◽  
Vol 21 (8) ◽  
pp. 2611-2631
Author(s):  
Sang-Guk Yum ◽  
Hsi-Hsien Wei ◽  
Sung-Hwan Jang
Keyword(s):  
South Korea ◽  
Water Level ◽  
Storm Surge ◽  
Storm Surges ◽  
Exceedance Probability ◽  
Probability Models ◽  
Distribution Models ◽  
Sea Levels ◽  
Extreme Storm ◽  
Gauge Data

Abstract. Global warming, one of the most serious aspects of climate change, can be expected to cause rising sea levels. These have in turn been linked to unprecedentedly large typhoons that can cause flooding of low-lying land, coastal invasion, seawater flows into rivers and groundwater, rising river levels, and aberrant tides. To prevent typhoon-related loss of life and property damage, it is crucial to accurately estimate storm-surge risk. This study therefore develops a statistical model for estimating such surges' probability based on surge data pertaining to Typhoon Maemi, which struck South Korea in 2003. Specifically, estimation of non-exceedance probability models of the typhoon-related storm surge was achieved via clustered separated peaks-over-threshold simulation, while various distribution models were fitted to the empirical data for investigating the risk of storm surges reaching particular heights. To explore the non-exceedance probability of extreme storm surges caused by typhoons, a threshold algorithm with clustering methodology was applied. To enhance the accuracy of such non-exceedance probability, the surge data were separated into three different components: predicted water level, observed water level, and surge. Sea-level data from when Typhoon Maemi struck were collected from a tidal-gauge station in the city of Busan, which is vulnerable to typhoon-related disasters due to its geographical characteristics. Fréchet, gamma, log-normal, generalized Pareto, and Weibull distributions were fitted to the empirical surge data, and the researchers compared each one's performance at explaining the non-exceedance probability. This established that Weibull distribution was better than any of the other distributions for modelling Typhoon Maemi's peak total water level. Although this research was limited to one city on the Korean Peninsula and one extreme weather event, its approach could be used to reliably estimate non-exceedance probabilities in other regions where tidal-gauge data are available. In practical terms, the findings of this study and future ones adopting its methodology will provide a useful reference for designers of coastal infrastructure.

IMPACT ASSESSMENT ON STORM SURGE RISKS TO CONTAINERS CONSIDERING GLOBAL WARMING

2017 ◽  
Author(s):  
Rikito Hisamatsu ◽  
Rikito Hisamatsu ◽  
Kei Horie ◽  
Kei Horie
Keyword(s):  
Risk Assessment ◽  
Global Warming ◽  
Storm Surge ◽  
Storm Surges ◽  
Assessment Tools ◽  
Inundation Depth ◽  
Risk Assessment Tools ◽  
Risk Maps ◽  
The Impact ◽  
Vulnerability Functions

Container yards tend to be located along waterfronts that are exposed to high risk of storm surges. However, risk assessment tools such as vulnerability functions and risk maps for containers have not been sufficiently developed. In addition, damage due to storm surges is expected to increase owing to global warming. This paper aims to assess storm surge impact due to global warming for containers located at three major bays in Japan. First, we developed vulnerability functions for containers against storm surges using an engineering approach. Second, we simulated storm surges at three major bays using the SuWAT model and taking global warming into account. Finally, we developed storm surge risk maps for containers based on current and future situations using the vulnerability function and simulated inundation depth. As a result, we revealed the impact of global warming on storm surge risks for containers quantitatively.

scholarly journals Storm Surges in the Bohai Sea: The Role of Waves and Tides

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1509
Author(s):  
Yuanyi Li ◽  
Huan Feng ◽  
Guillaume Vigouroux ◽  
Dekui Yuan ◽  
Guangyu Zhang ◽  
...  
Keyword(s):  
Storm Surge ◽  
Bohai Sea ◽  
Storm Surges ◽  
Wave Force ◽  
Laizhou Bay ◽  
Bohai Bay ◽  
Coastal Regions ◽  
The Bohai Sea ◽  
Tidal Phase ◽  
Set Up

A storm surge is a complex phenomenon in which waves, tide and current interact. Even though wind is the predominant force driving the surge, waves and tidal phase are also important factors that influence the mass and momentum transport during the surge. Devastating storm surges often occur in the Bohai Sea, a semi-enclosed shallow sea in North China, due to extreme storms. However, the effects of waves on storm surges in the Bohai Sea have not been quantified and the mechanisms responsible for the higher surges that affect part of the Bohai Sea have not been thoroughly studied. In this study, we set up a storm surge model, considering coupled effects of tides and waves on the surges. Validation against measured data shows that the coupled model is capable of simulating storm surges in the Bohai Sea. The simulation results indicate that the longshore currents, which are induced by the large gradient of radiation stress due to wave deformation, are one of the main contributors to the higher surges occurring in some coastal regions. The gently varying bathymetry is another factor contributing to these surges. With such bathymetry, the wave force direction is nearly uniform, and pushes a large amount of water in that direction. Under these conditions, the water accumulates in some parts of the coast, leading to higher surges in nearby coastal regions such as the south coast of the Bohai Bay and the west and south coasts of the Laizhou Bay. Results analysis also shows that the tidal phase at which the surge occurs influences the wave–current interactions, and these interactions are more evident in shallow waters. Neglecting these interactions can lead to inaccurate predictions of the storm surges due to overestimation or underestimation of wave-induced set-up.

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