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Evacuation time estimate (ETE) is an essential part of the preparedness for tsunami disaster risk reduction. Existing tsunami ETEs have been implemented using GIS-based methods or agent-based simulations; however, their evacuation departure estimates have largely relied on hypothetical scenarios or stated-preference surveys because of the lack of sufficient empirical observations. In this study, we analysed a region-wide evacuation survey conducted for the 2011 Tohoku tsunami to fill this gap. The survey included over 20000 behavioural trips collected from 49 coastal cities, which had the greatest area coverage and number of samples in existing studies. The analyses revealed that there were large variations in tsunami evacuation departures in different areas; that is, faster evacuation tendencies were found in the northern ria coastal areas compared with the southern plain areas. In contrast to the evacuation behaviour, the departure timing for milling exhibited smaller variations, suggesting that these behaviours were driven primarily by strong ground shaking. Our analysis indicates that delayed evacuation in the plains is linked to longer milling trips, influenced by regional characteristics. For enriched scenarios in tsunami ETEs, this large amount of evacuation data was compiled into three tsunami evacuation departure curves with different evacuation departure tendencies. • Over 20000 behavioural trips during the 2011 Tohoku tsunami were analysed. • Delayed evacuation in plain areas is linked to longer milling trips. • The large amount of data was compiled into three evacuation departure curves. [ABSTRACT FROM AUTHOR]

Abstract In the event of near-field tsunamis, vertical evacuation can be an alternative protective action to horizontal evacuation. The objective of this paper is to present an agent-based modeling (ABM) framework to evaluate vertical evacuation behavior and shelter locations for a near-field tsunami hazard from a Magnitude 9.0 Cascadia Subduction Zone (CSZ) earthquake. The expected mortality rate depending on the location of the vertical evacuation shelter (VES) has been chosen as the primary criterion to assess the effectiveness of the vertical evacuation. In addition, maximum tsunami wave height and the vertical evacuation behavior changes with changes in the placement of the VES have been assessed from a constraint point of view. The results revealed that (1) the choice of VES locations will directly impact the proportion of the people who evacuate vertically; (2) The percentage of people who evacuate vertically exponentially drops as the shelter gets farther from the population centroid; (3) the location of shelter significantly impacts the total mortality rates; (4) improvements in evacuees' mobility, such as faster walking speed or shorter milling time, will significantly reduce mortality rate and expand the area of choices for VES locations; and (5) when more people choose to evacuate vertically, the total mortality rate reduces notably. However, wrong placement of VES, and at the same time promoting vertical evacuation behavior can result in catastrophic mortality rates. In addition, a study on the impact of the distance of the VES to the ocean, to the population centroid, and to the horizontal shelters outside of the inundation zone, on the total mortality rate and the evacuation efficiency has been performed. This work reveals the non-linear correlation between the aforementioned characteristics of the VES on the expected mortality rate. The results of this research provide an evidence-driven vertical evacuation modeling framework to guide decision makers at city, state, and federal level to understand the dynamics of vertical evacuation behavior and choice of vertical evacuation shelter locations for a community. [ABSTRACT FROM AUTHOR]

Building emergency response systems for tsunamis is a common issue in tsunami prone areas. In these coastal regions, there are many tourist areas as well as residential areas. During the emergency state after an undersea earthquake and tsunami warning issued, tourism workers play a crucial role for tourists to evacuate to safety zones. This study explores tourism workers' perceptions of earthquake and tsunami risks and supporting tourists in the emergency stage following a massive earthquake. To analyze tourism workers' perceptions, we identify constructs of risk perceptions and supporting tourists. Differences in the perceptions among attributes are also illustrated in the analysis. To depict relationships among constructs and attributes, structural equation modeling was applied. The research site is Shirarahama area in Shirahama Town, Wakayama Prefecture, Japan which is a famous tourist and tsunami prone area. The target was tourism workers working in the estimated tsunami inundation area. The number of distributed questionnaires was 346, and the number of valid responses was 196 (56.6%). In the analysis result, the path from the latent variable of the perception of people's confusion to perceived behavioral control was statistically significant and negative. This result indicates that respondents who recognize tourists and other people in the area will be disrupted after a massive earthquake tend to recognize that they may be unable to implement necessary responses. Results also appeared that experience in the discussion of tsunami evacuation responses with colleagues and practical drills affected tourism workers' perceptions better than a seminar, paper material, or non-practical training. In tourist areas, it is essential to repeatedly implement practical drills assuming various situations after earthquakes and discuss and adjust the responses based on the necessary knowledge and accurate sense. [ABSTRACT FROM AUTHOR]

Tsunami evacuation is an effective way to save lives from the near-field earthquake-induced tsunami. To accurately assess tsunami evacuation risk, various uncertainties in evacuation need to be considered. For risk mitigation, it is also important to identify critical parameters (or risk factors) that contribute more to the evacuation risk to guide more effective tsunami evacuation. Probabilistic sensitivity analysis can be used for the latter. However, both risk assessment and sensitivity analysis require a large number of model evaluations and entail significant computational challenges, especially for the expensive evacuation model. This paper proposes an efficient augmented sample-based approach to address the above challenges. It only requires one set of samples/simulations (hence the high efficiency) to estimate the evacuation risk and calculate the sensitivity measures for all uncertain parameters. The approach is applied to estimate the tsunami evacuation risk for Seaside, Oregon, where a novel agent-based tsunami evacuation model is used to simulate the evacuation process more realistically. Various uncertainties in the evacuation process are explicitly quantified by properly selected probability distribution models. Besides the evacuation risk, critical risk factors are identified using probabilistic sensitivity analysis. The results provide important insights on tsunami evacuation and critical information for guiding effective evacuation risk mitigation. • Uses a novel agent-based tsunami evacuation model to simulate tsunami evacuation. • Explicitly quantifies various uncertainties in the evacuation process. • Uses an augmented sample-based approach for efficient analysis. • Only needs one set of samples to calculate sensitivity for all uncertain parameters. • Provides important insights on tsunamic evacuation and effective risk mitigation. [ABSTRACT FROM AUTHOR]

Many people visit or live in areas that are exposed to natural or technological hazards but lack sufficient information to protect themselves when a disaster threatens. Hazard and emergency managers in federal, state, local and tribal government, as well as scientists and educators in tsunami warning centers, try to meet this need by providing essential information about hazards and appropriate protective actions. To date, however, there has been limited guidance for the preparation of hazard education products such as maps and brochures. Accordingly, this article reviews research on hazard education, warning systems, and warning response, as well as research findings on the communication of textual, numeric, graphic, and cartographic information in risk messages. This review produced an evaluation rubric comprising eight criteria—1) general evaluation criteria, 2) hazard-specific content, 3) environmental cues content, 4) hazard warning (sources/channels/messages) content, 5) preparedness actions content, 6) response actions content, 7) numeric information, and 8) maps. These criteria are illustrated by four experts' evaluations of six tsunami evacuation products (TEPs—brochures and standalone maps). Although the small samples of raters and TEPs limit the generalizability of the results, this evaluation shows how hazard and emergency managers can assess the quality of preliminary TEP designs before conducting more scientifically rigorous evaluations using experimental or quasi-experimental designs. [ABSTRACT FROM AUTHOR]

Physical scientists have estimated that the Cascadia Subduction Zone (CSZ) has as much as a 25% chance to produce a M9.0 earthquake and tsunami in the next 50 years, but few studies have used survey data to assess household risk perceptions, emergency preparedness, and evacuation intentions. To understand these phenomena, this study conducted a mail-based household questionnaire using the Protective Action Decision Model (PADM) as a guide to collect 483 responses from two coastal communities in the CSZ: Crescent City, CA and Coos Bay, OR. We applied multistage regression models to assess the effects of critical PADM variables. The results showed that three psychological variables (risk perception, perceived hazard knowledge, and evacuation mode efficacy) were associated with some demographic variables and experience variables. Evacuation intention and evacuation mode choice are associated with those psychological variables but not with demographic variables. Contrary to previous studies, location and experience had no direct impact on evacuation intention or mode choice. We also analyzed expected evacuation mode compliance and the potential of using micro-mobility during tsunami response. This study provides empirical evidence of tsunami preparedness and intentions to support interdisciplinary evacuation modeling, tsunami hazard education, community disaster preparedness, and resilience plans. [ABSTRACT FROM AUTHOR]

Compared to evacuation behaviours, behaviours preceding evacuation including milling during tsunamis remain unclear. This study developed an analysis approach that evaluates the similarities in behaviour sequences throughout the evacuation process and investigated both the preceding behaviours and evacuation behaviours in Ishinomaki during the 2011 tsunami. The developed method was first applied to 101 detailed evacuation interview data and identified 16 major evacuation trip patterns in the study area during the 2011 tsunami. Then, we characterised the major patterns based on narratives and found key behavioural characteristics during tsunamis that both expanded and mitigated human loss. The analysis only considered the different destinations visited by people during evacuation processes; however, the proposed method successfully distilled evacuation processes with not only similar behavioural patterns but also similar thoughts or intentions. The collected behaviours revealed the complex evacuation processes during the tsunami, i.e., nearly half of the interviewees had two or more destinations in their evacuation trips. Evacuating alone was rarely observed, and many local residents first attempted to perform safety or damage confirmations, which caused evacuation delays. On the other hand, the results also indicated that this tendency of unification along with immediate school evacuation promoted evacuations in the study area by triggering household movements towards a hill, which unintentionally worked as a tsunami evacuation trip. We inferred that such secondary household movements potentially triggered other evacuation movements as tertiary effects by being sighted by other people. The findings of this study provide evidence suggesting that evacuation processes are largely affected by social structures or ties and highlight the importance of evacuation preparedness considering the revealed behaviour characteristics. [ABSTRACT FROM AUTHOR]

This paper aims to introduce an effective methodology for communicating a science-based tsunami risk scenario to non-expert citizens through consensus-making between disaster experts and non-experts, with the aid of four-way split-screen movie clips depicting evacuation scenarios. Action research on tsunami education in Zihuatanejo, Mexico found that a perception of tsunamis as catastrophic together with the one-directional nature of risk communication resulted in inaction on the part of non-experts in disaster preparedness, contrary to the expectations of experts. In other words, non-experts did not think that they could cope with a tsunami disaster and they perceived that as non-experts they themselves could not affect the tsunami risk scenario communicated to them by the experts. In response, movie clips simultaneously displaying a school evacuation drill and tsunami inundation simulation were developed. These movie clips are intended to serve as a tool in the process of establishing a school tsunami evacuation strategy by promoting consensus-making between experts and non-experts about the risk scenario, thereby helping to change the perception of a tsunami from a catastrophe that cannot be dealt with by non-experts to a realistic perception that non-experts can indeed help by engaging in their own tsunami risk preparedness activities. The developed movie clips were used at a workshop for stakeholders, including academics, local government, and teachers, with the aims of establishing scenario-based evacuation strategies and promoting the proactive implementation of preparedness activities by non-expert teachers. The study will contribute to establishing a mechanism for applying scientific knowledge to solving societal issues. [ABSTRACT FROM AUTHOR]

The November 14, 2016 Kaikōura earthquake in Aotearoa-New Zealand involved the rupture of 21 faults across North Canterbury, Marlborough, some of which extended offshore. The earthquake triggered a cascade of hazards including a localised 7 m tsunami. The Aotearoa-New Zealand tsunami research community sprang into action, providing advice around immediate tsunami risk and then collaborated to strategically investigate various aspects of the tsunami. Much of the Kaikōura Region was inaccessible for months after the event due to major damage to road networks, bridges, rail, and port. A coordinated effort across institutions and disciplines was needed to achieve the desired scientific goals while respecting the priorities of emergency services and affected communities as well as minimising the demands of a scientific response on these groups. Although this moderate-sized tsunami caused little damage, the event occurred in a region vulnerable to future tsunamis and therefore presents valuable lessons. The authors of this paper were personally involved in the science response and they present the successes and valuable lessons experienced by the tsunami research community in Aotearoa-New Zealand and compare these with guidelines for international post-tsunami field surveys for larger events. [ABSTRACT FROM AUTHOR]