Tsunami Evacuation Planning Research Articles

Examining the Impact of Risk Perception on the Accuracy of Anisotropic, Least-Cost Path Distance Approaches for Estimating the Evacuation Potential for Near-Field Tsunamis

Coastal hazards that can strike with little or no warning, such as tsunamis, are problematic in terms of population exposure and the threat of loss of life. With projected increases in coastal populations, exposure is likely to increase among these communities. For near-field tsunamis, the evacuation window can be as little as 15 to 20 min, and evacuation can be problematic for numerous reasons, such as population demographics, limited road networks, local topographic constraints, lack of proper education, and misaligned risk perception of the general populace. It is therefore critical for tsunami evacuation planning and education to be highly effective. To address this need, we employed a participatory mapping approach to explore potential evacuation enhancement by evaluating existing least-cost path pedestrian evacuation models, perception of landscape constraints, and additional risks to nearfield tsunamis in Aberdeen, Washington. Stakeholders were tasked with drawing their understood evacuation routes on maps which were analyzed for approximate time to reach safety and compared to least-cost path pedestrian evacuation models. A quantitative analysis of selected evacuation pathways revealed participants consistently overestimated evacuation time and did not follow modeled least-cost pathways. The results suggest traditional modeling (e.g., least-cost path and agent-based models) underestimate travel time to safety. Thus, there is a need for additional outreach, notably in communities where traditional evacuation models might create a false sense of security.

Evaluation of tsunami evacuation planning of the primary school student in Padang

This paper presents an evaluation of the tsunami evacuation of elementary school children in Padang. The objective of the study is to evaluate the evacuation planning using an observation data from an evacuation Experiment initiated by the Padang Regional Disaster Management Agency (BPBD Padang). In this study, the chosen evacuation destination was evaluated based on the available evacuation time, the evacuation methods, walking speed of the students in a group and the provided tools in the classroom for evacuation as in the guidelines of tsunami evacuation for schools in Hawaii.

Probabilistic Tsunami Hazard Assessment (PTHA) for resilience assessment of a coastal community

Probabilistic Tsunami Hazard Analysis (PTHA) can be used to evaluate and quantify tsunami hazards for planning of integrated community-level preparedness, including mitigation of casualties and dollar losses, and to study resilient solutions for coastal communities. PTHA can provide several outputs such as the intensity measures (IMs) of the hazard quantified as a function of the recurrence interval of a tsunami event. In this paper, PTHA is developed using a logic tree approach based on numerical modeling for tsunami generated along the Cascadia Subduction Zone. The PTHA is applied to a community on the US Pacific Northwest Coast located in Newport, Oregon. Results of the PTHA are provided for five IMs: inundation depth, flow speed, specific momentum flux, arrival time, and duration of inundation. The first three IMs are predictors of tsunami impact on the natural and built environment, and the last two are useful for tsunami evacuation and immediate response planning. Results for the five IMs are presented as annual exceedance probability for sites within the community along several transects with varying bathymetric and topographic features. Community-level characteristics of spatial distribution of each IM for three recurrence intervals (500, 1000, 2500 year) are provided. Results highlight the different pattern of IMs between land and river transects, and significant magnitude variation of IMs due to complex bathymetry and topographic conditions at the various recurrence intervals. IMs show relatively higher magnitudes near the coastline, at the low elevation regions, and at the harbor channel. In addition, results indicate a positive correlation between inundation depth and other IMs near the coastline, but a weaker correlation at inland locations. Values of the Froude number ranged 0.1–1.0 over the inland inundation area. In general, the results in this study highlight the spatial differences in IMs and suggest the need to include multiple IMs for resilience planning for a coastal community subjected to tsunami hazards.

Influence of residents’ cognition of their local environment on evacuation behavior from tsunamis: A case study of Onjuku, Chiba prefecture

AbstractThis paper focuses on the effects of residents’ cognition of their local environment on evacuation behavior in the event of a tsunami. We conducted questionnaire surveys and a sketch map survey in the coastal area of Onjuku, Chiba Prefecture. The results revealed the following: (i) evacuation implementation was influenced by cognition of the terrain around their home (the elevation from sea level and/or the distance from the sea) although it was not always correct; (ii) although reasons for choosing evacuation place were different from place to place, main reasons were the location (proximity and ground height) and the sense of safety; and (iii) some improper evacuation route choices (approached the sea, crossed rivers or decreased in elevation) were caused by “distorted” cognitive maps. These results suggest that understanding residents’ cognition is important in developing effective mitigation measures against tsunamis. The tsunami evacuation planning should include informing residents of the actual structure of the town and the appropriate direction for evacuation.

Inhabitants' Degree of Peace of Mind for Tsunami Evacuation Planning: Considering Local Community

Inhabitants' Degree of Peace of Mind for Tsunami Evacuation Planning: Considering Local Community

Visitors’ awareness of the tsunami evacuation plan in Pasar Raya Padang, Indonesia

This paper presents an investigation into the visitors’ awareness of the tsunami evacuation plan at Pasar Raya Padang, a traditional market at the central business district of Padang City, Indonesia. This study has been motivated by the fact that Pasar Raya Padang is the largest traditional market in West Sumatera and visited by many visitors from various origins. Pasar Raya Padang is chosen because it is located at a tsunami prone area, but local government managed to keep businesses in the area running and attract visitors. The awareness of the people in the market would be crucial to increase the possibility to safe their life during an evacuation. As much as 500 respondents were interviewed during daytime in the market. The study found that most of the visitors are not aware of the tsunami evacuation plan in the area. Local government is suggested to develop standard procedure for the evacuation, to place more sign and make it more visible for most of the visitors and do evacuation simulations periodically.

PRELIMINARY STUDY OF LSU-02 PHOTO DATA APPLICATION TO SUPPORT 3D MODELING OF TSUNAMI DISASTER EVACUATION MAP

The southern coast of Pacitan Regency is one of the vulnerable areas to the tsunami. Therefore, the map of the vulnerable and safe area from the tsunami disaster is required. Currently, there are many mapping technologies with UAVs used for spatial analysis. One of the UAV technologies which used in this research is LAPAN Surveillance UAV 02 (LSU-02). This study aims to map the evacuation plan area from LSU-02 aerial imagery. Tsunami evacuation area was identified by processing the aerial photo data into orthomosaic and Digital Elevation Model (DEM). The result shows that there are four points identified as the tsunami evacuation plan area. These points are located higher than the surrounding area and are easily accessible.

Tsunami evacuation plans for future megathrust earthquakes in Padang, Indonesia, considering stochastic earthquake scenarios

Abstract. This study develops tsunami evacuation plans in Padang, Indonesia, using a stochastic tsunami simulation method. The stochastic results are based on multiple earthquake scenarios for different magnitudes (Mw 8.5, 8.75, and 9.0) that reflect asperity characteristics of the 1797 historical event in the same region. The generation of the earthquake scenarios involves probabilistic models of earthquake source parameters and stochastic synthesis of earthquake slip distributions. In total, 300 source models are generated to produce comprehensive tsunami evacuation plans in Padang. The tsunami hazard assessment results show that Padang may face significant tsunamis causing the maximum tsunami inundation height and depth of 15 and 10 m, respectively. A comprehensive tsunami evacuation plan – including horizontal evacuation area maps, assessment of temporary shelters considering the impact due to ground shaking and tsunami, and integrated horizontal–vertical evacuation time maps – has been developed based on the stochastic tsunami simulation results. The developed evacuation plans highlight that comprehensive mitigation policies can be produced from the stochastic tsunami simulation for future tsunamigenic events.

Scenario-Based Tsunami Evacuation Analysis: A Case Study of Haimen Town, Taizhou, China

In current tsunami prevention and mitigation, evacuation is the most important method of saving people’s lives. Tsunami evacuation is analyzed for a given travel time and a specific inundation area. Before evacuation analysis, the tsunami inundation and tsunami travel time are first calculated by numerical modeling. This paper analyzes the tsunami evacuation of Haimen Town, Jiaojiang District, Taizhou City, China, under the hypothesis of a magnitude 9.0 earthquake scenario in the Ryukyu Trench. The Cornell multi-grid coupled tsunami (COMCOT) model and Tsunami Travel Time (TTT) model are used to calculate the tsunami inundation and tsunami travel time, respectively. GIS techniques are used to solve the evacuation problem. Both horizontal and vertical evacuations are adopted based on the Chinese community characteristics, disaster prevention facilities, land use, and other practical conditions. A cost raster is used to analyze the arrival cost of each grid in the study area. The location allocation and cost allocation methods are used to solve shelter selection and coverage problems, respectively. The network analyst is applied to provide evacuation routes for each community. The evacuation analysis results can provide a scientific reference for the development of tsunami evacuation plans.

Tsunami simulations of mega-thrust earthquakes in the Nankai–Tonankai Trough (Japan) based on stochastic rupture scenarios

Abstract In this study, earthquake rupture models for future mega-thrust earthquakes in the Nankai–Tonankai subduction zone are developed by incorporating the main characteristics of inverted source models of the 2011 Tohoku earthquake. These scenario ruptures also account for key features of the national tsunami source model for the Nankai–Tonankai earthquake by the Central Disaster Management Council of the Japanese Government. The source models capture a wide range of realistic slip distributions and kinematic rupture processes, reflecting the current best understanding of what may happen due to a future mega-earthquake in the Nankai–Tonankai Trough, and therefore are useful for conducting probabilistic tsunami hazard and risk analysis. A large suite of scenario rupture models is then used to investigate the variability of tsunami effects in coastal areas, such as offshore tsunami wave heights and onshore inundation depths, due to realistic variations in source characteristics. Such investigations are particularly valuable for tsunami hazard mapping and evacuation planning in municipalities along the Nankai–Tonankai coast.

Vulnerability Analysis of a School Building Under Tsunami Loading in the Gulf of Cadiz

This work aims to study the impact of tsunami on special buildings by simulating and analyzing the behavior of a test school building under tsunami forces. A school building represents a strategic element that requires the adoption of a plan for immediate evacuation in case of a tsunami threat. In this work, the different aspects of the study elements are presented, namely the site of study which is supposedly located in the region of the gulf of Cadiz, the architectural plan of the test school building, the building code adopted in designing the frame’s cross section, characteristics and expressions for the eventual tsunami forces, and finally the software simulation methodology. Then, the vulnerability of the test building is analyzed through by generating capacity and fragility curves. The obtained capacity curve is compared to the pushover curve that describes the behavior of the building in case of a seismic solicitation. In the other hand, fragility curves are compared to statistical data from previous tsunami events. An interpretation is given to the results and a detailed discussion is presented about the similarities and differences between the curves. Finally, some advantages of this work are illustrated, such as the objectivity of the tsunami vulnerability assessment, and the ability for analyzing particular buildings which can represent, more or less, an important solution for tsunami evacuation plans.

Tsunami evacuation buildings and evacuation planning in Banda Aceh, Indonesia

Indonesia, a country of more than 17,000 islands, is exposed to many hazards. A magnitude 9.1 earthquake struck off the coast of Sumatra, Indonesia, on December 26, 2004. It triggered a series of tsunami waves that spread across the Indian Ocean causing damage in 11 countries. Banda Aceh, the capital city of Aceh Province, was among the most damaged. More than 31,000 people were killed. At the time, there were no early warning systems nor evacuation buildings that could provide safe refuge for residents. Since then, four tsunami evacuation buildings (TEBs) have been constructed in the Meuraxa subdistrict of Banda Aceh. Based on analysis of evacuation routes and travel times, the capacity of existing TEBs is examined. Existing TEBs would not be able to shelter all of the at-risk population. In this study, additional buildings and locations for TEBs are proposed and residents are assigned to the closest TEBs. While TEBs may be part of a larger system of tsunami mitigation efforts, other strategies and approaches need to be considered. In addition to TEBs, robust detection, warning and alert systems, land use planning, training, exercises, and other preparedness strategies are essential to tsunami risk reduction.

Planning Assessment of Tsunami Evacuation Plan at Community Level

Planning Assessment of Tsunami Evacuation Plan at Community Level

Influence of road network and population demand assumptions in evacuation modeling for distant tsunamis

Tsunami evacuation planning in coastal communities is typically focused on local events where at-risk individuals must move on foot in a matter of minutes to safety. Less attention has been placed on distant tsunamis, where evacuations unfold over several hours, are often dominated by vehicle use and are managed by public safety officials. Traditional traffic simulation models focus on estimating clearance times but often overlook the influence of varying population demand, alternative modes, background traffic, shadow evacuation, and traffic management alternatives. These factors are especially important for island communities with limited egress options to safety. We use the coastal community of Balboa Island, California (USA), as a case study to explore the range of potential clearance times prior to wave arrival for a distant tsunami scenario. We use a first-in–first-out queuing simulation environment to estimate variations in clearance times, given varying assumptions of the evacuating population (demand) and the road network over which they evacuate (supply). Results suggest clearance times are less than wave arrival times for a distant tsunami, except when we assume maximum vehicle usage for residents, employees, and tourists for a weekend scenario. A two-lane bridge to the mainland was the primary traffic bottleneck, thereby minimizing the effect of departure times, shadow evacuations, background traffic, boat-based evacuations, and traffic light timing on overall community clearance time. Reducing vehicular demand generally reduced clearance time, whereas improvements to road capacity had mixed results. Finally, failure to recognize non-residential employee and tourist populations in the vehicle demand substantially underestimated clearance time.

Pedestrian flow-path modeling to support tsunami evacuation and disaster relief planning in the U.S. Pacific Northwest

Successful evacuations are critical to saving lives from future tsunamis. Pedestrian-evacuation modeling related to tsunami hazards primarily has focused on identifying areas and the number of people in these areas where successful evacuations are unlikely. Less attention has been paid to identifying evacuation pathways and population demand at assembly areas for at-risk individuals that may have sufficient time to evacuate. We use the neighboring coastal communities of Hoquiam, Aberdeen, and Cosmopolis (Washington, USA) and the local tsunami threat posed by Cascadia subduction zone earthquakes as a case study to explore the use of geospatial, least-cost-distance evacuation modeling for supporting evacuation outreach, response, and relief planning. We demonstrate an approach that uses geospatial evacuation modeling to (a) map the minimum pedestrian travel speeds to safety, the most efficient paths, and collective evacuation basins, (b) estimate the total number and demographic description of evacuees at predetermined assembly areas, and (c) determine which paths may be compromised due to earthquake-induced ground failure. Results suggest a wide range in the magnitude and type of evacuees at predetermined assembly areas and highlight parts of the communities with no readily accessible assembly area. Earthquake-induced ground failures could obstruct access to some assembly areas, cause evacuees to reroute to get to other assembly areas, and isolate some evacuees from relief personnel. Evacuation-modeling methods and results discussed here have implications and application to tsunami-evacuation outreach, training, response procedures, mitigation, and long-term land use planning to increase community resilience.

Visual exploration of tsunami evacuation planning

We present a novel web browser-based interactive visualization tool to aid in rapid tsunami evacuation planning. The interface loads simulated route-schedule flow data for visual analysis and allows users to explore the spatio-temporal evolvement of an evacuation process with a dynamic map. It also supports multiple filtering and summary interaction, i.e., filtering the roads/nodes by their utilization efficiency and summarizing the congested roads during evacuation. The multiple linked views including some diagrams facilitate the analysis of evacuation efficiency and verifying of evacuation schedules. Our tool also supports dynamic evacuation parameter settings to help to make the evacuation strategies and optimize decision-making. A case study on the possible tsunami evacuation events is conducted with disaster managers and domain experts. Encouraging remarks on usability and performance were received.

Tsunami Inundation Map and Its Application on Evacuation Planning in Taiwan

The casualty and impact induced by the 2011 Tohoku tsunami event and the earthquake in Japan drew considerable attention of Taiwanese government and civilian to review what we have accomplished for tsunami disaster prevention. However, at that time, there was no applicable tsunami potential data for local governments in Taiwan to draw the tsunami evacuation plans. Therefore, the simulation result is adopted in this study to produce the first version of tsunami inundation maps for coastal cities/counties in Taiwan. Furthermore, a planning guideline including analytical procedure and methodology is proposed to help local governments make tsunami evacuation plans using tsunami inundation maps. Examples are given in each analytical step to illustrate typical outcomes and suggestions on planning based on local conditions. This guideline and tsunami inundation maps have been submitted to central and local governments for evacuation planning. The application in one county is chosen as an example to demonstrate the practical achievement of this study. A thorough tsunami evacuation planning associated with education and training is crucial to disaster prevention of tsunami.

Response to the 2011 Great East Japan Earthquake and Tsunami disaster.

We revisited the lessons of the 2011 Great East Japan Earthquake Tsunami disaster specifically on the response and impact, and discussed the paradigm shift of Japan's tsunami disaster management policies and the perspectives for reconstruction. Revisiting the modern histories of Tohoku tsunami disasters and pre-2011 tsunami countermeasures, we clarified how Japan's coastal communities have prepared for tsunamis. The discussion mainly focuses on structural measures such as seawalls and breakwaters and non-structural measures of hazard map and evacuation. The responses to the 2011 event are discussed specifically on the tsunami warning system and efforts to identify the tsunami impacts. The nation-wide post-tsunami survey results shed light on the mechanisms of structural destruction, tsunami loads and structural vulnerability to inform structural rehabilitation measures and land-use planning. Remarkable paradigm shifts in designing coastal protection and disaster mitigation measures were introduced, leading with a new concept of potential tsunami levels: Prevention (Level 1) and Mitigation (Level 2) levels according to the level of 'protection'. The seawall is designed with reference to Level 1 tsunami scenario, while comprehensive disaster management measures should refer to Level 2 tsunami for protection of human lives and reducing potential losses and damage. Throughout the case study in Sendai city, the proposed reconstruction plan was evaluated from the tsunami engineering point of view to discuss how the post 2011 paradigm was implemented in coastal communities for future disaster mitigation. The analysis revealed that Sendai city's multiple protection measures for Level 2 tsunami will contribute to a substantial reduction of the tsunami inundation zone and potential losses, combined with an effective tsunami evacuation plan.

Tsunami Safe Town Planning with Evacuation Simulation

Tsunami evacuation plans have been deliberately developed by local governments in coastal areas in Japan under guidance from the national government since before the Great East Japan Earthquake in March 2011. These plans, however, do not mention the time required for all local residents to evacuate to evacuation areas. This paper reports a procedure to design an effective tsunami safe town planning using multi-agent simulator (MAS) which identify a degree of evacuation risk in objective area. A case study is applied to one of the worst hit town of tsunami, in which additional facilities such as evacuation areas, safe buildings, and evacuation routes are proposed as well.

Impact of a tsunami generated at the Lesser Antilles subduction zone on the Northern Atlantic Ocean coastlines

Abstract. On 11 March 2011, a Mw ~ 9.0 megathrust earthquake occurred off the coast of Tohoku, triggering a catastrophic tsunami reaching heights of 10 m and more in some places and resulting in lots of casualties and destructions. It is one of a handful of catastrophic tsunamis having occurred during the last decade, following the 2004 Indonesian tsunami, and leading to the preparation of tsunami warning systems and evacuation plans all around the world. In the Atlantic Ocean, which has been struck by two certified transoceanic tsunamis over the past centuries (the 1755 "Lisbon" and 1929 Grand Banks events), a warning system is also under discussion, especially for what concerns potential tsunamigenic sources off Iberian Peninsula. In addition, the Lesser Antilles subduction zone is also potentially able to generate powerful megathrust ruptures as the 8 February 1843 Mw ~ 8.0/8.5 earthquake, that could trigger devastating tsunamis propagating across the Northern Atlantic Ocean. The question is in which conditions these tsunamis could be able to reach the Oceanic Islands as well as the eastern shores of the Atlantic Ocean, and what could be the estimated times to react and wave heights to expect? This paper attempts to answer those questions through the use of numerical modelings and recent research results about the Lesser Antilles ability to produce megathrust earthquakes.