Tsunami Evacuation Planning Research Articles

Evaluation of Tsunami Evacuation Plans for an Underground Mall Using an Agent-Based Model

Tsunamis resulting from earthquakes can cause extensive damage, including infrastructure destruction, injuries, and fatalities. To address these risks, numerous tsunami evacuation simulations have been conducted to assess evacuation strategies and identify issues, particularly in Japan, where the Nankai Trough earthquake is anticipated, affecting underground malls in urban areas. Our previous research primarily focused on evacuating from underground to the surface, neglecting surface evacuation. Therefore, this study extended the previous study to include horizontal evacuation following the exit from the underground mall to ground level. It also considered the impact of pedestrian road crossings as interactions with vehicular traffic within the simulation to enhance realism and verify the evacuation risk. The study also explores scenarios where evacuation guide stairs are unavailable, comparing the effectiveness of alternative staircases in the evacuation plan. Results indicate that while using alternative staircases temporarily increases the number of evacuees reaching the surface, road crossings on evacuation routes become significant bottlenecks, leading to surface congestion and delayed evacuations. This raises doubts about the effectiveness of alternative staircases and highlights the need to consider alternative evacuation routes as a secondary plan. Additionally, the study reveals that reduced pedestrian flow at road crossings can significantly impact on evacuation times. Ultimately, this study demonstrated that achieving a short evacuation time from underground malls to the ground level might not always yield the best evacuation plan. It underscored the importance of considering aboveground factors in evacuation planning to ensure safety in the event of a tsunami caused by an earthquake.

Environmental perspective on tsunami disaster mitigation and its implications: a critical review

Tsunamis are one of the deadliest and most destructive natural disasters, having the potential to cause significant damage to the environment and society. Therefore, tsunami hazard modeling becomes very important in disaster risk management and environmental protection. Tsunami evacuation isan important and effective effort that must be carried out to save the community when a tsunami occurs. The aim of this study is to review the environmental perspective on the tsunami evacuation plan in terms of environmental, social, and economic aspects, along with their implications. Aqualitativedescriptive study was carried out through a literature review by comparing case studies in various coastal areas affected by the tsunami. Environmental factors play an important role in the results of tsunami modeling which will form the basis for evacuation plans.Social and economic aspects also play a role in people's behavior when evacuating, reviewed and observed, in order to produce an effective and sustainable evacuation plan.

Architecture-Oriented Agent-Based Simulations and Machine Learning Solution: The Case of Tsunami Emergency Analysis for Local Decision Makers

Tsunamis are a perilous natural phenomenon endangering growing coastal populations and tourists in many seaside resorts. Failures in responding to recent tsunami events stresses the importance of further research in building a robust tsunami warning system, especially in the “last mile” component. The lack of detail, unification and standardisation in information processing and decision support hampers wider implementation of reusable information technology solutions among local authorities and officials. In this paper, the architecture of a tsunami emergency solution is introduced. The aim of the research is to present a tsunami emergency solution for local authorities and officials responsible for preparing tsunami response and evacuation plans. The solution is based on a combination of machine learning techniques and agent-based modelling, enabling analysis of both real and simulated datasets. The solution is designed and developed based on the principles of enterprise architecture development. The data exploration follows the practices for data mining and big data analyses. The architecture of the solution is depicted using the standardised notation and includes components that can be exploited by responsible local authorities to test various tsunami impact scenarios and prepare plans for appropriate response measures.

Analysis of the occurrence of evacuation assistance for wheelchair users by tsunami evacuation drill observations

AbstractIn 2011, the Great East Japan Earthquake caused great damage to the elderly and disabled, as well as many of the people who supported their evacuation. Various measures and evacuation drills are under way for evacuation of vulnerable people, and when evacuating, it is often decided who will support the evacuation of the vulnerable people. However, there is a need for a mindset that anyone can become an evacuation supporter because there is a possibility that it will not go as set in the actual situation. Therefore, in this study, in order to enable more efficient evacuation of wheelchairs, we measured the evacuation speed and observed an evacuation drill conducted in Nakatosa Town, and examined them separately in 4 phases: preparation, evacuation start time, evacuation action time, and evacuation spare time. As a result, factors to be reflected in evacuation drill and assistance action types for wheelchair evacuation were derived. By incorporating the verification used in this study into the tsunami evacuation plan, we hope to contribute to reducing human damage, including those who vulnerable people and their supporters.

Tsunami preparedness within Sri Lanka's education system

Asked what hazard posed the greatest threat to their school, the principals of coastal schools in the Galle, Ampara and Batticaloa districts of Sri Lanka overwhelmingly responded “tsunami”. This result is unsurprising considering the scale and trauma caused by the December 26, 2004 Indian Ocean tsunami. This tsunami claimed over 35,000 victims in Sri Lanka, a third of whom were children. It damaged and destroyed 182 schools, and a further 287 served as camps for internally displaced persons. Given that Sri Lanka is far from all potential sources of earthquake-induced tsunami, and that there is time for early warning and evacuation, it is crucial that coastal schools are prepared and ready to act. This study uses semi-structured interviews with school principals and regional education and disaster management officials to gain insights into the tsunami preparedness of the Sri Lankan education sector. Overall, our findings show that schools are heavily reliant on tsunami early warning towers for their warning, yet only half of the 430 Sri Lankan schools exposed to tsunami are within audible range of a tsunami early warning tower. It is crucial therefore that alternative and backup early warning channels are established where needed. However, the interviews show that there is a very low level of baseline hazard preparedness. There are few or no fire drills, let alone tsunami evacuation plans or drills. The school principals express the view clearly that the education system in Sri Lanka is ill-prepared for a future tsunami. We find however that there are opportunities to involve existing safety committees in school preparedness and in the development of evacuation plans; and to exploit existing regular teacher curriculum training events to develop capacities in emergency response and evacuation. Importantly, experiences from a past tsunami drill with Sri Lankan communities emphasise the importance of holding regular school practice drills as well as “end-to-end” (from tsunami detection to tsunami evacuation) community evacuation exercises.

Simulated Mitigation of Tsunami Disasters in the Coastal Area of Purworejo Regency, Central Java, Indonesia

The coastal area of Purworejo Regency has the potential to be hit by a mega-tsunami disaster because it includes the southern coast of Java Island which is faced with seismic gaps that may produce large earthquakes in the future. This study aims to simulate tsunami disaster mitigation in the coastal area of Purworejo Regency in an effort to raise awareness and increase the community capacity for dealing with potential tsunamis so that the level of loss can be minimized. The tsunami risk analysis is based on the Disaster Crunch model, which is a combination of vulnerability analysis based on the weighted overlay quantitative method and tsunami hazard analysis based on tsunami inundation reduction modeling and cost distance analysis. The planning of the tsunami evacuation route is based on the network analysis method. The tsunami-risk area with a run-up scenario of three meters in the coastal area of Purworejo Regency 126,29 square kilometers or about 72,52% of the total coastal area. There are five tsunami evacuation plan points, with five main tsunami evacuation routes that lead directly to each of these points.

Can Homecare Chronic Respiratory Disease Patients with Home Oxygen Treatment (HOT) in Southern Okinawa, Japan Be Evacuated Ahead of the Next Anticipated Tsunami?

An earthquake with a magnitude of 8 or 9 is predicted to occur near the Ryukyu Islands in Japan, for which the Okinawa Prefecture is preparing countermeasures. Evacuating people to a safe shelter within the tsunami arrival time is a crucial countermeasure. This study aims to understand the vulnerabilities of patients with chronic respiratory diseases in southern parts of Okinawa during a tsunami evacuation, thereby calculating evacuation distance of vulnerable patients and creating individual evacuation plans. Data for chronic respiratory patients obtained in July 2021 from the hospitals in Okinawa Prefecture include age, gender, diagnosis, residence, nearest tsunami shelter, oxygen flow at rest and walking, and maximum walking distance for 6 min based on a 6-min walk test. A quantum geographic information system was used for mapping the data. The survival potential of patients with chronic respiratory disease was evaluated by using a tsunami inundation depth of one meter and the distance within which an evacuation can be performed until the first tsunami wave reaches the nearest evacuation shelter. Results revealed a low survival potential for respiratory disease patients under the current tsunami evacuation plan. The study suggests creating an individual evacuation plan for vulnerable patients involving families and medical staff and then conducting a drill for improving the plan.

Proposal of a Tsunami Evacuation Plan Considering Cumulative Capacity in the Evacuation Place and Evacuation outside the Tsunami Inundation Area

Proposal of a Tsunami Evacuation Plan Considering Cumulative Capacity in the Evacuation Place and Evacuation outside the Tsunami Inundation Area

Numerical Analysis of Evacuation Start in Pangandaran

Tsunami evacuations plan should consider the behavior of local people. In this study tsunami evacuation start was analyzed using tsunami evacuation simulation consist of evacuee generation and evacuee behavior model. Pangandaran west beach was selected as the target area due to its popularity as a tourist spot and fishery activities in West Java. Evacuation simulations were conducted using 500 evacuations agents with tsunami shelter and grand mosques as goal for the safer place. A total of six evacuation scenarios were made using a different set of evacuation triggers parameter value with the combination of influence weight and effective range. The simulation result indicates that the influence weight which made 57% of people start evacuation immediately after the earthquake happened showed an instantaneous evacuation. Simulation result that was using lower influence weight and lower exposure range showed a more gradual tsunami evacuation. The simulation gave promising results that Pangandaran people could be safely evacuating if they raise their awareness and preparedness. The low-cost simulations that were used in this study provide an insight into the behaviors of Indonesians during disaster evacuation and might use as support for tsunami evacuation planning. However, to produce more satisfactory result we need to conduct field survey and tsunami drill to gain more information of people behavior during tsunami evacuation.

Mapping of IOC-UNESCO Tsunami Ready Indicators in the Pangandaran Village, Indonesia

Pangandaran Village is a tourist village located in Pangandaran Regency, West Java Province, Indonesia. The beautiful view of sand beaches and abundant marine resources make Pangandaran Village has great economic potential. However, in 2006, an earthquake with a magnitude of 7.7 Mw triggered a tsunami disaster in the Pangandaran area that caused more than 600 fatalities, injuries, and damage to buildings, especially in Pangandaran Village. Based on current research, there is potential for an 8.7 magnitude earthquake off the south coast of Java in the near future, triggering an enormous tsunami. The coastal community in Pangandaran Regency has been building a tsunami risk reduction strategy to anticipate the tsunami disaster. In Pangandaran Village, the local community is piloting the 12 tsunami ready indicators following the guideline from UNESCO-IOC. Therefore, this study aims to map 12 tsunami ready IOC-UNESCO indicators in Pangandaran Village to evaluate which indicators the government and community of Pangandaran Village. The method used in mapping 12 tsunami ready indicators in Pangandaran Village is to take data in the field by doing aerial photographs, conducting interviews with the village government and other related local stakeholders, mapping tsunami evacuation plan and infrastructure, and disseminating questionnaires to the community to find out the response to the tsunami disaster. Based on the IOC-UNESCO tsunami indicator mapping results, all indicators have been fulfilled. However, several other aspects of tsunami preparedness indicators still need to be improved to strengthen tsunami preparedness in Pangandaran.

Mini Special Issue on Tsunami Numerical Modeling Benchmarks – Challenges of Tsunami Modeling Hackathon –

Numerical simulation and modeling became an essential technology in tsunami research and disaster management. Various numerical models were proposed and utilized for the development of tsunami risk assessment, inundation maps, and evacuation plans. The model verification and validation standards would be crucial to ensure sufficient reliability of tsunami risk assessment, inundation maps, as well as a consistency among various efforts. Common approach to ensure sufficient accuracy and reliability of numerical modeling is developing benchmark problems of hydraulic experiments and to use them for numerical model’s verification and validation. To satisfy this requirement, “Tsunami Modeling Hackathon” was held in September 2020 to organize new benchmark problems in numerical modeling of tsunamis and to improve their reliability and accuracy. Hackathon is an intensive-gathering event of computer programmers and others involved in software development to create outcomes by the end of the event. This event was organized by Prof. Tomoyuki Takahashi of Kansai University and his colleagues, who led the tsunami research subcommittee in Japan Society of Civil Engineers (JSCE). Tsunami modeling hackathon, in which about 23 teams and 162 researchers joined, included experiment and modeling teams in seven benchmark problems: urban tsunami inundation, landslide tsunami, tsunami loading on seawalls and coastal structures, sediment transport, drift of floating objects. The modeling groups performed the blind tests to cross-validate and interpret the results of their simulations in seven benchmark problems given by the experiment groups and discussed the improvement. This special issue reports the outcomes of the tsunami modeling hackathon, and includes six papers (five in this issue, one in the regular issue). We hope this issue will provide useful insights for tsunami modelers and contribute to establishing a standardized way to ensure that various tsunami numerical models would be validated through the benchmark problems.

GIS-based study of tsunami risk in the Special Region of Yogyakarta (Central Java, Indonesia)

The island of Java is located above a plate boundary within the Indonesian archipelago as part of the volcanic arc resulting from the subduction of the Indo–Australian plate beneath the Eurasian plate. Due to its emplacement, it is exposed to several geohazards, including active volcanoes and earthquakes, and its secondary effects (e.g., landslides, tsunamis). Tsunamis have repeatedly hit Java; for example, the 17th of July 2006 caused by an Mw 7.8 earthquake off the coast of western Java, or the 22nd of December 2018 triggered by the collapse of the flank of Anak Krakatau during its eruption. In most cases, tsunamis have a destructive coastal impact and can cause a significant loss of lives. Therefore, it is of high importance to determine areas situated in tsunami risk zones and estimate plans for risk reduction and prevention. We present an ArcGIS-based method to calculate tsunami risk zones for the Special Region of Yogyakarta (Central Java), including the calculation of hazard zones, vulnerability zones, and the estimation of highly exposed areas. The final risk map reflects the current risk zones in the occurrence of a tsunami and should be recalculated and re-evaluated if the environmental and socio-economic conditions change. The results can be used as a base for tsunami evacuation plans and site planning.

Planning tsunami vertical evacuation routes using high-resolution UAV digital elevation model: case study in Drini Coastal Area, Java, Indonesia

Tsunami evacuation is a short process that must be carried out in minutes. Determining the evacuation routes and safe areas is equally important in tsunami evacuation planning. It can be established from least cost distance (LCD) anisotropic model. We use the coastal of Drini, Gunungkidul, Java, Indonesia, as the study area, which is located in a tropical coastal karst region, with a typical karst cone formation. The topographic condition of the karst cone could be an ideal location for tsunami vertical evacuation (TVE). High-resolution orthomosaic images and digital elevation model (DEM) generated from the structure from motion (SfM) process were used as the main data. The tsunami inundation model was calculated based on neighboring operations using raster calculator from the elevation value in the DEM. Land cover identification from high-scale orthomosaic images showed the variation in speed conservation values (SCVs). The slope value was also used as a surface cost that will affect the travel time to the TVE shelters. The results of the model show that TVE is the main alternative in tsunami evacuation planning beside horizontal evacuation. They provide an evaluation of the location of the assembly points and evacuation routes provided by the government, which have been considered ineffective because of the inappropriate model. The results of the study provide an overview of determining the evacuation routes and shelters. Optimum locations can minimize travel time, provide adequate capacity, and be safe from inundation.

Tsunami evacuation times and routes to safe zones: a GIS-based approach to tsunami evacuation planning on the island of Stromboli, Italy

While a landslide at the volcanic island of Stromboli (Aeolian Islands, Italy) in December 2002 created a tsunami with a run-up of 10.9 m, two paroxysmal eruptions in the summer of 2019 caused a tsunami with an amplitude of 40 to 20 cm. All three events required rapid, spontaneous emergency evacuations of the beach zone as the time between tsunami generation and impact is around 4 min. These conditions thus require a special consideration of the issue of evacuation capabilities on the island in the event of a volcanogenic tsunami. The purpose of this paper is thus to (i) determine pedestrian evacuation times from high-risk coastal areas to safe zones, (ii) to assess building evacuation ease, and (iii) determine emergency evacuation plans (for buildings and coastal zones). For this purpose, we created a GIS-based risk analysis/mapping tool that also allowed macroscopic evacuation modelling. In our case, the high-risk zone to be evacuated involves an area extending to 10 m a.s.l. and involving 123 individual buildings over an area of 0.18 km2. The results show that 33% of the buildings can be evacuated in 4 min, and that a 10-min warning time is required for a complete and well-distributed evacuation whereby the population is evenly distributed between all evacuation exits to avoid the potential for congestion. Initial interviews of residents in the at-risk zone reveal a high level of awareness and a desire for personalized evacuation scenarios.

Multiscale Quantification of Tsunami Hazard Exposure in a Pacific Small Island Developing State: The Case of Samoa

This study presents a scenario-based approach for identifying and comparing tsunami exposure across different sociopolitical scales. In Samoa, a country with a high threat to local tsunamis, we apply scenarios for the 2009 South Pacific tsunami inundation at different grid resolutions (50 and 10 m) to quantify building and road exposure at the national, district and village levels. We show that while the coarser 50 m model is adequate for use in the rapid identification of exposure at the national and district levels, it can overestimate exposure by up to three times more at the village level. Overestimation typically occurs in areas characterized by flat, low-lying, gentle-rising terrain. Overall, a 35% increase in buildings exposed to the 50 m model is observed compared with the 10 m scenario on southeast Upolu island. Similarly, a 31% increase in road exposure is observed for the 50 m scenario. These observations are discussed within the context of tsunami evacuation planning and logistics. Notwithstanding the variability in exposure, a precautionary approach leads us to conclude that while higher-resolution models are recommended where available data and/or financial resources permit, the absence of such datasets should not preclude the use of coarser hazard datasets in risk assessments. Finer-resolution models provide more credence in detailed local-level exposure evaluation. While the results of this study are specific to the Samoan context, the results can be applied to the multiscale assessment of tsunami risk exposure in similar hazard contexts.

Are current tsunami evacuation approaches safe enough?

Developing an effective tsunami evacuation plan is essential for disaster risk reduction in coastal regions. To develop effective tsunami evacuation plans, real transportation network, interaction among evacuees, and uncertainties associated with future tsunami events need to be considered in a holistic manner. This study aims to develop such an integrated tsunami evacuation approach using agent-based evacuation simulation and advanced stochastic tsunami hazard assessment. As a case study, a urban area in Padang, Indonesia, threatened by tsunamis from the Mentawai–Sunda subduction zone, is adopted. The uncertainty of the tsunami hazard is taken into account by generating 900 stochastic tsunami inundation maps for three earthquake magnitudes, i.e. 8.5, 8.75, and 9.0. A simplified evacuation approach considering the evacuees moving directly to evacuation areas (defined a priori) is compared with two more rigorous agent-based modeling approaches: (a) a two-destination-point tsunami evacuation plan developed by the local government and (b) a multiple-destination-point plan developed in this study. The improved agent-based stochastic tsunami evacuation framework with multiple destinations takes advantage of the extensive tsunami hazard analyses to define safe areas in a dynamic manner and is capable of capturing the uncertainty of future tsunami risk in coastal areas. In contrast, the results clearly show that the simplified approach significantly underestimates the evacuation time, and the existing tsunami evacuation routes identified by local authorities may be insufficient to save lives.

Influence of demand and capacity in transportation simulations of short-notice, distant-tsunami evacuations

Distant tsunamis require short-notice evacuations in coastal communities to minimize threats to life safety. Given the available time to evacuate and potential distances out of hazard zones, coastal transportation planners and emergency managers can expect large proportions of populations to evacuate using vehicles. A community-wide, short-notice, distant-tsunami evacuation is challenging because it creates a sudden, significant, and concentrated demand on road-network systems. Transportation planners and emergency managers need methods to help them determine if a road network can handle an evacuation surge and if not, where interventions can best reduce overall clearance times. We use the coastal community of Bay Farm Island (City of Alameda, California, USA) and the distant-tsunami threat posed by Aleutian-Alaskan earthquakes as a case study to explore the use of agent-based, transportation simulation to support short-notice, tsunami-evacuation planning. Results demonstrate how vehicle simulation can characterize network performance during a tsunami evacuation in the absence of real-world measurements of vehicle demand and flow. Changes in vehicle demand had the greatest influence on reductions in clearance times and recommended reductions varied based on time of day. Doubling the capacity of certain road segments based on traditional vehicle-capacity ratios and level-of-service thresholds reduced overall clearance time in some cases but increased it in other cases. The proposed simulation approach can serve as an analytical foundation for future efforts to characterize distant-tsunami evacuations in other coastal communities throughout the world.

Challenges in increasing community preparedness against tsunami hazards in tsunami-prone small islands around Sumatra, Indonesia

Fifteen years since the 2004 Indian Ocean tsunami, which caused massive destruction around the Andaman Sea, people have participated in efforts to reduce tsunami risks in Indonesia. However, the most important question continues to be on whether such efforts are sufficient in dealing with tsunami risks. Among the most striking challenges here is bridging the gap in tsunami risk reduction between the Sumatra mainland and among communities in several small islands. Thus, this research aims to investigate the recent conditions of selected towns/cities in tsunami-prone small islands and identify the impediments to their tsunami hazard preparedness. It focuses on comparing efforts in terms of available facilities for tsunami evacuation plans and the tsunami estimated time of arrival (ETA), which is computed based on deterministic tsunami propagation models. In this regard, five of the observed locations are classified as being in a critical tsunami preparedness condition, namely Balai island, Lahewa of Nias Island, Sabeugunggung of North pagai Island, Surat Aban of South Pagai island, and Enggano Island. Most of them have limited space for tsunami evacuation and a short tsunami ETA, which constitutes an extreme condition requiring immediate tsunami mitigation measures. One possible approach is to construct a vertical tsunami evacuation building or modify existing buildings that can be used for tsunami evacuation on the islands. This article also highlights societal aspects related to tsunami preparedness.

Effectiveness of hard and soft tsunami countermeasures on loss of life under different population scenarios

The present study proposes a comprehensive investigation of the tsunami-evacuation plans for a popular coastal area considered to be at high risk for tsunami attack. If a coastal region constitutes a renowned sightseeing location or has a popular beach, numerous tourists and beach users could be at risk of a tsunami. However, tsunami risk management strategies have generally been developed considering only local residents, and the effects of the presence of tourist on the effectiveness of countermeasures have rarely been taken into account. To investigate changes in the effectiveness of tsunami countermeasures under different population scenarios, the authors further developed an existing agent-based tsunami evacuation simulation model. Through the application of this model to Yuigahama Beach in Kamakura City, Japan, it was found that the effectiveness of hard measures (i.e., elevating the road embankment) is slightly influenced by the numbers and types of evacuees who are present on or near the beach when a tsunami arrives. However, the effectiveness was greatly influenced by the type of soft measures (i.e., changing the evacuation behaviour) employed. It was also shown that, if there are many evacuees in a coastal area, soft measures merely aiming at early evacuation and guiding evacuees to the closest evacuation place via the shortest route could instead worsen the fatality rate. The present study thus sheds further light on the importance of establishing tsunami mitigation strategies that focus on the tourist population, in order to minimize the number of fatalities that could result from a future event.

Assessment of Bridges for Tsunami Evacuation Route Plan in Padang: Survey of Existing Condition and Identification of Problems

Padang, as one of the tsunami prone city in the world, had already prepared itself for the upcoming event. Local government already issued tsunami evacuation plan, and assigned several buildings as temporary evacuation facilities or shelters. One important thing in this mitigation plan is the performance of the infrastructures as roads and bridges. Bridges are essential since any damages or failures leads to disruption or even widespread jam of traffic after the big earthquake. Draft of new seismic code for bridges in Indonesia suggests that bridges for evacuation plan must be designed with very limited damage or near elastic design. This study attempts to identify bridges that are included in tsunami evacuation plan route and summarizes the existing condition. The collected data and information are important and could be used as basic for future studies such as retrofit plan.