Publisher：Lecture Notes in Civil Engineering  

Heavy rainfall is a frequent and widespread severe weather hazard that may cause flood damage and human casualties. Since heavy rainfall is a progressive disaster, its scale and hazardous areas can be foreseen beforehand. Therefore, evacuating people from hazardous buildings to shelters in advance is an efficient effort to reduce casualties, but a scientific basis is still required. This paper proposes an approach for assessing each building’s evacuation vulnerability based on predicted evacuation time, aiming to support evacuation decision-making under heavy rainfall. As such, this paper applies Dijkstra’s algorithm to find the evacuation route from each building to accessible shelters. Moreover, a prediction model based on the random forest algorithm is developed to estimate their time-varying evacuation time. Road spatial and temporal characteristics that may affect evacuation time are used when developing the model. Finally, the proposed approach is implemented in Joso City, Japan, to verify its feasibility. As a result, the proposed approach accurately predicts and visualizes the evacuation time between each building and its optimal evacuation shelter. It also visually identifies the hard-to-evacuate buildings. The results indicate that the proposed approach can effectively reflect evacuation vulnerability and support heavy rainfall evacuation decision-making, which proves its validity and practicality.

DOI： 10.1007/978-981-99-9219-5_2

Web of Science

Scopus

Language：Japanese   Publisher：Institute of Social Safety Science  

<p>During heavy rainfall disasters, quantitative assessments of disaster risk are necessary to support municipalities' decision to issue evacuation information and residents' decision on whether to evacuate has been noted. In this research, two disaster risk assessment methods are proposed for municipalities and residents, based on the evacuation time. Afterwards, in a flood scenario of Joso City, the lead-time of municipalities' evacuation decisions has been calculated by the municipality-oriented assessment method. Meanwhile, the temporal variation of evacuation difficulty of each resident has been quantified by resident-oriented assessment method. As a result, the proposed methods have been considered feasible to support the evacuation decisions of municipalities and residents.</p>

DOI： 10.11314/jisss.43.9

CiNii Research

Publisher：International Journal of Disaster Risk Reduction  

Flooding is a frequent natural hazard, threatening people's lives and properties worldwide. Even though completely preventing damage from flooding is impossible, an appropriate evacuation can help minimize its impact and mitigate human casualties. However, analyzing various flooding information to make quick evacuation judgments is challenging for decision-makers. Therefore, a quantitative flooding risk assessment is needed to support appropriate evacuation decisions. This study introduces the travel time under ideal evacuation conditions to quantify evacuation vulnerability, with Dijkstra's algorithm finding the evacuation route and the Random Forest algorithm predicting the evacuation time. The evacuation vulnerability is then integrated with time-varying flooding hazards and estimated congestion levels to assess evacuation risk. Herein, a case study in Joso, Japan is used as an example to demonstrate the practicality and applicability of the proposed approach. As a result, the prediction model achieved high accuracy with an RMSE of 0.88min and a MAPE of 5.88 %. The proposed approach clearly illustrated the vulnerable areas and times that may hinder an efficient evacuation process. Also, this approach identified and visualized the individual evacuation risk distribution during a given flooding scenario: 49.38 % of buildings were assessed as having the highest-risk: no evacuation ability, while a maximum of 11.86 % and 3.83 % of the buildings were assessed as middle-risk and high-risk. Furthermore, the regional evacuation deadline and priorities were specified to ensure timely and effective evacuation. Overall, this study develops an approach for assessing evacuation vulnerability and risk that could facilitate awareness among the public and provide judgmental bases for evacuation preparedness and decision-making.

DOI： 10.1016/j.ijdrr.2023.104113

Web of Science

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：公益社団法人 日本オペレーションズ・リサーチ学会  

豪雨災害などの進行型災害において，自治体はさまざまな情報を基に避難情報発令の対象やタイミングを判断する必要がある．しかし，定性的な根拠に基づく判断では適切な避難情報発令は困難である．適切な避難情報発令には，定量的な根拠に基づいて判断を行うことが望ましい．そのためには，さまざまな情報から災害リスクを定量化して評価する必要がある．本稿では，避難時の災害リスクの定量化を目的として，避難所要時間に着目した災害リスクの新たな評価指標を開発するとともに，その避難判断支援における有用性について検討した事例について概説する．

Authorship：Lead author,　Last author   Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)   Publisher：公益社団法人土木学会