Chen, Chen; Koll, Charles; Wang, Haizhong; Lindell, Michael K . 2023. “An Interdisciplinary Agent-Based Evacuation Model: Integrating the Natural Environment, Built Environment, and Social System for Community Preparedness and Resilience.” Natural Hazards and Earth System Sciences 23 (2).
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Abstract
Previous tsunami evacuation simulations have mostly been based on arbitrary assumptions or inputs adapted from non-emergency situations, but a few studies have used empirical behavior data. This study bridges this gap by integrating empirical decision data from surveys on local evacuation expectations and evacuation drills into an agent-based model of evacuation behavior for two Cascadia subduction zone (CSZ) communities that would be inundated within 20–40 min after a CSZ earthquake. The model also considers the impacts of liquefaction and landslides from the earthquake on tsunami evacuation. Furthermore, we integrate the slope-speed component from least-cost distance to build the simulation model that better represents the complex nature of evacuations. The simulation results indicate that milling time and the evacuation participation rate have significant nonlinear impacts on tsunami mortality estimates. When people walk faster than 1 m s -1 , evacuation by foot is more effective because it avoids traffic congestion when driving. We also find that evacuation results are more sensitive to walking speed, milling time, evacuation participation, and choosing the closest safe location than to other behavioral variables. Minimum tsunami mortality results from maximizing the evacuation participation rate, minimizing milling time, and choosing the closest safe destination outside of the inundation zone. This study's comparison of the agent-based model and the beat-the-wave (BtW) model finds consistency between the two models' results. By integrating the natural system, built environment, and social system, this interdisciplinary model incorporates substantial aspects of the real world into the multi-hazard agent-based platform. This model provides a unique opportunity for local authorities to prioritize their resources for hazard education, community disaster preparedness, and resilience plans. [ABSTRACT FROM AUTHOR]
Lindell, Michael K., Meen Chel Jung, Carla S. Prater, and Donald H. House. 2023. “US Pacific Coast Communities’ Past Preparedness and Preparedness Intentions for Cascadia Subduction Zone Tsunamis.” International Journal of Disaster Risk Reduction 84.
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Abstract
This study examined tsunami awareness and preparedness by 225 respondents in three communities exposed to Cascadia Subduction Zone (CSZ) tsunamis. Some participants viewed a tsunami brochure, but all participants reported their degree of information sufficiency about tsunamis and protective actions to take when a tsunami threatens, expected warning sources for local and distant tsunamis, past preparedness actions and preparedness intentions, tsunami experience, past tsunami information, perceived tsunami zone, and demographic characteristics. In addition to the results showing that the brochure had a significant positive effect on tsunami information sufficiency and expected warning sources, the latter two variables affected intentions to engage in future preparedness actions. In addition, tsunami experience, past tsunami infor-mation, and past preparedness also affected these variables. Although psychological responses were significantly related to preparedness intentions, they were not related to hypothesized antecedent variables-tsunami experience, past preparedness, past information, and de-mographic characteristics. The data suggest that emergency managers can promote tsunami hazard education by distributing comprehensive tsunami brochures, but should also work with local news media to direct CSZ residents to agency web sites where they can access additional information about tsunami hazard, expected warning sources, appropriate preparedness, and response actions.
Keywords
Cascadia subduction zone tsunamis; Risk communication; Tsunami hazard awareness; Tsunami preparedness
Lindell, Michael K; Jung, Meen Chel; Prater, Carla S; House, Donald H (2023). Evaluation of Hazard Brochures Using Topic Viewing Durations: Application to Tsunami Evacuation Brochures. Risk Analysis.
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Abstract
This study describes a novel method of assessing risk communication effectiveness by reporting an evaluation of a tsunami information brochure by 90 residents of three Pacific coast communities that are vulnerable to a Cascadia Subduction Zone earthquake and tsunami—Commencement Bay, Washington; Lincoln City, Oregon; and Eureka, California. Study participants viewed information that was presented in DynaSearch, an internet‐based computer system that allowed them to view text boxes and tsunami inundation zone maps. DynaSearch recorded the number of times each text box or map was clicked and the length of time that it was viewed. This information viewing phase was followed by questionnaire pages assessing important aspects of tsunami hazard and sources of tsunami warnings. Participants gave the longest click durations to what to do in the emergency period during earthquake shaking and in its immediate aftermath before a tsunami arrives—topics that should be displayed prominently in tsunami brochures and emphasized in talks to community groups. The smallest adjusted click durations were associated with advance preparations for a tsunami—topics that can be posted on websites whose URLs are printed in the brochures.
Keywords
DynaSearch; hazard awareness brochure; Protective Action Decision Model
In the United States, flooding is a leading cause of natural disasters, with congressional budget office estimates of $54 billion in loss each year. Although both urban and rural areas are highly vulnerable to flood hazards, most natural disaster resilience studies have focused primarily on urban areas, overlooking rural communities. One such area that has been overlooked are the numerous rural communities bordering the Great Lakes. These communities face unprecedented challenges due to rising water levels, particularly since 2012, which have resulted in increased coastal flood hazard. Despite their flooding risk, they continue to lack flood hazard assessments and inundation maps, exacerbating their vulnerability. The Federal Emergency Management Agency (FEMA) commonly recommend counties to use a freely available tool—called HAZUS to develop hazard mitigation plans and enhance community resilience and adaptation. However, the usage of HAZUS for rural communities is challenging due to existing data gaps that limit the analytical potential of HAZUS in these communities. Continued use of standard datasets for HAZUS analysis by rural counties could likely leave the communities underprepared for future flood events. The proposed project’s vision is to develop methods that use remote sensing data resources and citizen engagement (crowdsourcing) to address current data gaps for improved flood hazard modeling and visualization that is scalable and transferable to rural communities.
The results of the project will expand the traditional frontiers of preparedness and resilience to natural disasters by drawing on the expertise and backgrounds of investigators working at the interface of geological engineering, civil engineering, computer science, marine engineering, urban planning, social science, and remote sensing. Specifically, the proposed research will promote intellectual discovery by i) improving our understanding of remote sensing data sources and open-source processing methods to assist rural communities in addressing the data gaps in flood hazard modeling, ii) developing sustainable geospatial visualization tools for communicating hazards to communities, iii) advancing our understanding of the utility of combining remote sensing and crowdsourcing to flood hazard delineation, iv) understanding ways to incentives the crowd for greater participation and accuracy in hazard in addressing natural disasters, and v) identifying critical community resilience indicators through crowdsourcing. These advancements will lead to prepared and resilient rural communities that can effectively mitigate hazards related to lake level rise and flooding.
While community lifeline service providers and local emergency managers must maintain coordinated response and recovery plans, their timelines may not match expectations of local consumers of lifeline services. Indeed, it is quite likely consumers have unrealistic expectations about lifeline restoration, which could explain current inadequate levels of disaster preparedness. This hypothesized expectation gap has received little attention because engineering research typically addresses providers’ capacities, whereas disaster research addresses household and business preparedness. Our project will address this neglected issue by assessing consumers’ (households, business owners/managers, nonprofit managers) expectations about lifeline system performance, and comparing them to lifeline provider capacity in a post-hazard event scenario (following a Cascadia subduction zone earthquake of 9.0 magnitude or greater) in two communities—Kirkland and Shoreline, WA (likely to experience most shaking in this scenario).
Our research will assess the role of the expectations gap in influencing consumers’ and providers’ preparedness as well as response. First, we estimate the gap between consumers and providers expectations using an earthquake scenario in two case study communities. We posit that low consumer preparedness for lifeline disruption is in part a function of low expectations that lengthy disruption will occur. Next, we test the effect of providing consumers and providers with information about this gap. Our proposed sharing estimates of lifeline restoration times should change these beliefs if our assumption about this specific basis for low preparedness is correct and if our audiences attend to, process, and act upon this information. In our longitudinal research, consumers (households, businesses, and nonprofits) and lifeline providers will complete two questionnaires each. Besides lifeline provider surveys, we will collect information about lifeline providers’ capabilities and work with them to estimate restoration times using an expert elicitation-based estimation framework. We will address the following research questions:
- What do consumers think is the likely level of critical lifeline disruption from an earthquake and the timeline for restoration?
- What are consumers’ current levels of preparedness for lifeline interruption?
- What do lifeline providers and an independent engineering expert think are providers’ capabilities to maintain and restore lifeline services?
- How do consumers’ expectations compare with providers’ capabilities (expectations gap)?
- How will this study’s feedback about the expectations gap affect consumers’ and providers’ lifeline resilience expectations, as well as their mitigation and preparedness intentions?
Lindell, Michael K.; Jung, Meen Chel; Prater, Carla S.; House, Donald H. (2022). Improving Cascadia Subduction Zone Residents’ Tsunami Preparedness: Quasi-experimental Evaluation of an Evacuation Brochure. Natural Hazards, 114(1), 849-881.
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Abstract
This study surveyed 227 residents in three US Pacific Coast communities that are vulnerable to a Cascadia subduction zone tsunami. In the Brochure condition, information was presented online, followed by questions about tsunamis. Respondents in the Comparison condition received the same questionnaire by mail but did not view the brochure. Respondents in the Brochure condition had higher levels of perceived information sufficiency than those in the Comparison condition about three of the five tsunami topics. Both conditions had generally realistic expectations about most tsunami warning sources. However, they had unrealistically high expectations of being warned of a local tsunami by social sources, such as route alerting, that could not be implemented before first wave arrival. They also had unrealistically high expectations being warned of a distant tsunami by ground shaking from the source earthquake, whose epicenter would be too far away for them to feel. Moreover, respondents in both conditions expected higher levels of personal property damage and family casualties than is the case for most hazards, but their levels of negative affective response were not especially high. Overall, only 10% of the sample accessed the tsunami brochure even when sent repeated contacts and the brochure demonstrated modest effects for those who did access it. These results suggest that state and local officials should engage in repeated personalized efforts to increase coastal communities' tsunami emergency preparedness because distribution of tsunami brochures has only a modest effect on preparedness.
Keywords
Subduction Zones; Tsunamis; Emergency Management; Tsunami Warning Systems; Brochures; Preparedness; Communities; Cascadia Subduction Zone Tsunami; Hazard Warnings; Quasi-experiment; Risk Communication; Risk Information-seeking; Natural Warning Signs; Earthquake; Awareness; Responses; Behavior; Model; Wellington; Hazard; Threat; Earthquakes; Casualties; Subduction; Vulnerability; Emergency Preparedness; Emergency Warning Programs; Levels; Seismic Activity; Property Damage; Shaking; Earthquake Damage; Subduction (geology); Disaster Management; Cascadia
Doyle, Emma E. H.; Mcclure, John; Potter, Sally H.; Becker, Julia S.; Johnston, David M.; Lindell, Michael K.; Johal, Sarbjit; Fraser, Stuart A.; Coomer, Maureen A. (2018). Motivations to Prepare After the 2013 Cook Strait Earthquake, N.Z. International Journal Of Disaster Risk Reduction, 31, 637 – 649.
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Abstract
We investigated responses to the 2013 Cook Strait earthquake sequence, New Zealand. This included two foreshocks (M5.7 and M5.8) and a mainshock doublet pair: M6.5 Cook Strait (CS) earthquake on 21st July and M6.6 Lake Grassmere (LG) earthquake on Friday 16th August. We examined relationships between preparedness, experience and beliefs during the earthquakes, as well as concern and subsequent preparedness actions. Results indicate that earthquake characteristics (e.g., time, location) influence the types of preparedness actions. While there was a reduction in new actions from the first mainshock doublet earthquake (CS) to the second (LG), there were a large number of participants who reviewed or revisited their prior actions, related to their beliefs about impacts, in a form of problem-focused targeted action. Females took more actions than did males, and had a higher rate of immediate aftershock concern. For all participants, concern was greater after the CS earthquake than after the full earthquake sequence, supporting the findings of McClure et al. (2016) that there is a limited window after an event to maximise the opportunity for effective preparedness initiatives. Findings additionally suggest that such post-earthquake preparedness initiatives should consider the impacts that elicited the highest rate of concern in an event, and should tailor messages towards them. While this earthquake sequence resulted in low levels of impact and damage, it presents interesting findings regarding how disruption (in lieu of major damage) influences earthquake preparedness actions, which is particularly important to understand in highly active regions often exposed to smaller impact events.
Keywords
Seismic Hazard Adjustments; Risk Communication; Decision-making; Natural Hazards; Unrealistic Optimism; Different Regions; Volcanic Crisis; Perception; Disaster; Behavior; Earthquakes; Preparedness; Beliefs; Concern; Actions; Gender
Jon, Ihnji; Huang, Shih-kai; Lindell, Michael K. (2018). Perceptions and Reactions to Tornado Warning Polygons: Would a Gradient Polygon Be Useful? International Journal Of Disaster Risk Reduction, 30, 132 – 144.
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Abstract
To better understand people's interpretations of National Weather Service's tornado warning polygons, 145 participants were shown 22 hypothetical scenarios in one of four displays-deterministic polygon, deterministic polygon + radar image, gradient polygon, and gradient polygon + radar image. Participants judged each polygon's numerical strike probability (p(s)) and reported the likelihood of taking seven different response actions. The deterministic polygon display produced p(s) that were highest at the polygon's centroid and declined in all directions from there. The deterministic polygon + radar display, the gradient polygon display, and the gradient polygon + radar display produced p(s) that were high at the polygon's centroid and also at its edge nearest the tornadic storm cell. Overall, p(s) values were negatively related to resuming normal activities, but positively correlated with expectations of resuming normal activities, seeking information from social sources, seeking shelter, and evacuating by car. These results replicate the finding that participants make more appropriate p(s) judgments when polygons are presented in their natural context of radar images than when the polygons are presented in isolation and that gradient displays appear to provide no appreciable benefit. The fact that p(s) judgments had moderately positive correlations with both sheltering (a generally appropriate response) and evacuation (a generally inappropriate response) provides experimental confirmation that people threatened by actual tornadoes are conflicted about which protective action to take.
Keywords
Protective Action; Uncertainty; Risk; Psychology; Casualties; Tornado Warning Polygons; Risk Perceptions; Protective Actions
Jon, Ihnji; Huang, Shih-Kai; Lindell, Michael K. (2019). Perceptions and Expected Immediate Reactions to Severe Storm Displays. Risk Analysis, 39(1), 274 – 290.
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Abstract
The National Weather Service has adopted warning polygons that more specifically indicate the risk area than its previous county-wide warnings. However, these polygons are not defined in terms of numerical strike probabilities (p(s)). To better understand people's interpretations of warning polygons, 167 participants were shown 23 hypothetical scenarios in one of three information conditions-polygon-only (Condition A), polygon + tornadic storm cell (Condition B), and polygon + tornadic storm cell + flanking nontornadic storm cells (Condition C). Participants judged each polygon's p(s) and reported the likelihood of taking nine different response actions. The polygon-only condition replicated the results of previous studies; p(s) was highest at the polygon's centroid and declined in all directions from there. The two conditions displaying storm cells differed from the polygon-only condition only in having p(s) just as high at the polygon's edge nearest the storm cell as at its centroid. Overall, p(s) values were positively correlated with expectations of continuing normal activities, seeking information from social sources, seeking shelter, and evacuating by car. These results indicate that participants make more appropriate p(s) judgments when polygons are presented in their natural context of radar displays than when they are presented in isolation. However, the fact that p(s) judgments had moderately positive correlations with both sheltering (a generally appropriate response) and evacuation (a generally inappropriate response) suggests that experiment participants experience the same ambivalence about these two protective actions as people threatened by actual tornadoes.
Keywords
Decision-making; Tornado; Risk; Communication; Numeracy; Residents; Shelter; Events; Protective Actions; Risk Perceptions; Tornado Warning Polygons; Judgments; Tornadoes; Meteorological Services; Storms; Lymphocytes B; Polygons; Emergency Warning Programs; Evacuation; Displays; Inappropriateness; Weather; Warnings; Conditions; Ambivalence
Lindell, Michael K.; Arlikatti, Sudha; Huang, Shih-kai. (2019). Immediate Behavioral Response to the June 17, 2013 Flash Floods in Uttarakhand, North India. International Journal Of Disaster Risk Reduction, 34, 129 – 146.
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Abstract
The 2013 Uttarakhand flash flood was such a surprise for those at risk that the predominant source of information for their risk was environmental cues and, secondarily, peer warnings rather than official warnings. Of those who received warnings, few received information other than the identity of the flood threat. A survey of 316 survivors found that most people's first response was to immediately evacuate but some stayed to receive additional information, confirm their warnings, or engage in evacuation preparations. Unfortunately, engaging in these milling behaviors necessarily delayed their final evacuations. Mediation analysis revealed that psychological reactions mediated the relationship between information sources and behavioral responses. Further analyses revealed that immediate evacuation and evacuation delay were both predicted best by information search and positive affect, but correlation analyses indicated that a number of other models were also plausible. Final evacuation was best predicted by immediate evacuation and, to a significantly lesser extent, household together. Overall, results suggest that the Protective Action Decision Model (PADM) should be considered a useful framework for examining household responses to flash floods in developing countries like India. It supports the conclusion that a household's first warning source is a function of two distinct detection and dissemination systems within a community-an official system and an informal system. However, it fails to capture what pre-impact emergency preparedness entails for rapid onset events in a developing country context. Further research is needed to determine the relative importance of situational and cultural characteristics in producing these observed differences.
Keywords
Risk Perception; Mental Models; Warnings; Evacuation; Disaster; Tsunami; Communication; Earthquake; Beliefs; Hazard; Flash Flood; Warning; Psychological Reactions; India