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Identifying recurrent and persistent landslides using satellite imagery and deep learning: A 30-year analysis of the Himalaya

Tzu-Hsin Karen Chen, Mark E. Kincey, Nick J. Rosser, Karen C. Seto, Identifying recurrent and persistent landslides using satellite imagery and deep learning: A 30-year analysis of the Himalaya, Science of The Total Environment, Volume 922, 2024, 171161, ISSN 0048-9697, https://doi.org/10.1016/j.scitotenv.2024.171161.

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Abstract

This paper presents a remote sensing-based method to efficiently generate multi-temporal landslide inventories and identify recurrent and persistent landslides. We used free data from Landsat, nighttime lights, digital elevation models, and a convolutional neural network model to develop the first multi-decadal inventory of landslides across the Himalaya, spanning from 1992 to 2021. The model successfully delineated >265,000 landslides, accurately identifying 83 % of manually mapped landslide areas and 94 % of reported landslide events in the region. Surprisingly, only 14 % of landslide areas each year were first occurrences, 55–83 % of landslide areas were persistent and 3–24 % had reactivated. On average, a landslide-affected pixel persisted for 4.7 years before recovery, a duration shorter than findings from small-scale studies following a major earthquake event. Among the recovered areas, 50 % of them experienced recurrent landslides after an average of five years. In fact, 22 % of landslide areas in the Himalaya experienced at least three episodes of landslides within 30 years. Disparities in landslide persistence across the Himalaya were pronounced, with an average recovery time of 6 years for Western India and Nepal, compared to 3 years for Bhutan and Eastern India. Slope and elevation emerged as significant controls of persistent and recurrent landslides. Road construction, afforestation policies, and seismic and monsoon activities were related to changes in landslide patterns in the Himalaya.

Keywords

Landslide inventory; Landslide evolution; Vegetation recovery; Multi-temporalSpatiotemporal analysis; Machine learning

Dan Abramson working with Westport, WA community to create a tsunami response plan

Dan Abramson is one of the researchers working with costal town Westport, WA to develop a tsunami response plan. Abramson is an Associate Professor in the Urban Design and Planning department. “When the ‘big one’ hits — a magnitude 9.0 or higher Cascadia subduction zone earthquake — researchers and officials predict that within minutes of the shaking a wall of water reaching 40 feet tall will inundate the coastline, including Westport.” This indicates the importance of this response plan.  Read…

Understanding the role of individual- and community-based resources in disaster preparedness

Nguyễn, L. T., Bostrom, A., Abramson, D. B., & Moy, P. (2023). Understanding the role of individual- and community-based resources in disaster preparedness. International Journal of Disaster Risk Reduction, 96, 103882–. https://doi.org/10.1016/j.ijdrr.2023.103882

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Abstract

Standard emergency management practice in the U.S measures disaster preparedness as an individual household attribute based on amounts of stocked supplies, hazard mitigation actions, and emergency planning. Such measures generally fail to consider how norms of trust, fairness, and reciprocity, as well as networks of social relationships—that is, social capital—can facilitate coordination and enable sharing and communal action in the face of disaster. Our study assesses how shared resources, social capital, and day-to-day resources (specifically, food and water) could influence earthquake disaster preparedness across different communities. Using Seattle as the site of investigation, the study involved a split-ballot experiment embedded in a mail survey of a random sample of households. These households were stratified by zip codes selected for their contrasting demographics (N = 1340). Half of the households in each zip code answered conventional individualistic measures of disaster preparedness, while the other half answered questions regarding resources they, their family, friends, and neighbors might share. In racial-majority-dominated zip codes, reported preparedness was higher when people were asked to consider shared resources. Disaster preparedness also appeared to be underestimated with the traditional measure. Households with greater bridging social capital (connections with individuals who differ in their social identity but who may share some similar interests) and longer neighborhood tenure also reported higher preparedness. Our findings suggest disaster preparedness efforts should focus on supplementing individual preparedness with daily resources, social capital, and collective shareable community assets—a focus that we call “mainstreaming.”

Keywords

Disaster preparedness; Social capital; Asset-based; Readiness; Resilience; Earthquakes

Factors Influencing Willingness to Share Resources Postdisaster: A Cross-Cultural Comparison between US and Japanese Communities

Idziorek, K., Abramson, D. B., Kitagawa, N., Yamamoto, T., & Chen, C. (2023). Factors Influencing Willingness to Share Resources Postdisaster: A Cross-Cultural Comparison between US and Japanese Communities. Natural Hazards Review, 24(4). https://doi.org/10.1061/NHREFO.NHENG-1836

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Abstract

When large-scale disasters occur, people often are left on their own to seek critical resources: food, water, medications, and other important items. Historically, government agencies have developed disaster preparedness strategies focused primarily on either the level of the individual or household or on the ability of government agents to provide relief to affected areas. Such approaches do not consider the potential for community members to share needed resources with one another—a crucial factor in survival when earthquakes, floods, landslides, and other disruptions to transportation and communications cut off whole communities from external aid. In this study, we used a simple random sample survey to measure households’ actual and perceived preparedness and assess individuals’ willingness to share essential resources following a large disaster using survey data gathered from three communities in the Pacific Northwest of the US (𝑁=638; overall response rate 20.1%) and Nagoya, Japan (𝑁=1,043; response rate 13.6%), two regions that expect to experience a magnitude 9.0 megaquake. Analysis of the survey data using an ordered response probit model found that the strength of social ties and levels of social trust strongly influence willingness to share in both regions. Differences between the Japanese and American responses suggest different dependencies on and roles for government agencies in the two societies, as well as differences in the types of resources that community members are willing to share, and with whom. Trust emerges as the most important factor across both study regions and for all resources. Willingness to share may be enhanced through trust-building interventions and should be regarded as an effective focus for preparedness efforts, especially if it is shown to be beneficial for a variety of social purposes.

Johnston-Hastings Endowment 2023 Travel Awardee

Robert Hutchison, an affiliate associate professor in the Architecture department, is selected to receive the Johnston-Hastings Travel Award for 2023. The Johnston-Hastings endowment supports travel-related expenses to further research goals. Professor Hutchison’s work will take place in late summer and early fall 2023, and will involve travel and research throughout Washington and Oregon. Dissemination of this work is expected in Spring 2024. For more information about the Johnston-Hastings Endowment awards, please visit the research funding opportunities page on the intranet.

Population Health Initiative awards College of Built Environments researchers a spring quarter 2023 Tier 1 pilot grant

The Population Health Initiative announced the award of nine Tier 1 pilot grants to interdisciplinary research teams representing 10 of the University of Washington’s schools and colleges. The total award value of these grants is nearly $210,000, which includes school, department and unit matching funds. Read more in the CBE Story here. “We were extremely pleased with the range of challenges these awards will work to address,” said Ali H. Mokdad, the UW’s chief strategy officer for population health and professor of…

An Interdisciplinary Agent-Based Evacuation Model: Integrating the Natural Environment, Built Environment, and Social System for Community Preparedness and Resilience

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]

 

US Pacific Coast Communities’ Past Preparedness and Preparedness Intentions for Cascadia Subduction Zone Tsunamis

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

Integrating Health Considerations into Local Level Recovery Planning: An Exploration of Florida’s Recovery and Redevelopment Plans

Archer, Megan, Pedersen, Katherine, Kennedy, Mallory, & Errett, Nicole A. (2022). Integrating Health Considerations into Local Level Recovery Planning: An Exploration of Florida’s Recovery and Redevelopment Plans. Journal of Disaster Research, 17(7), 1150–1157.

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Abstract

Objective: Disasters result in impacts to the health and wellbeing of members of affected communities, as well as damage to healthcare infrastructure. These impacts are not experienced equally, and often disproportionately affect those facing higher health, social and economic risks even before a disaster strikes. Recovery planning provides an opportunity for pre-emptive consideration of how to address pre-existing health vulnerabilities and disparities, as well as insufficient and/or inequitable access to healthcare, with the resources and momentum that often come following a disaster. After the 2004 and 2005 hurricane seasons, Florida began requiring coastal jurisdictions to plan for recovery. This study sought to identify if and how Florida jurisdictions have integrated health-sector restoration and revitalization strategies into local disaster recovery planning. Design: Plans were collected and coded using content analysis methods. Setting: Florida, USA. Participants: 16 county-level disaster recovery and post-disaster redevelopment plans. Results: While nearly three-quarters of plans described actions to address both short-term healthcare and behavioral health needs, the majority of recovery plans lacked long-term health-sector recovery activities and approaches to collect and analyze data to guide health-related recovery efforts. Moreover, plans did not explicitly call for evaluating health-sector recovery strategies. Conclusions: Additional resources are necessary to ensure local jurisdictions integrate short- and long-term health-sector strategies into disaster recovery planning.

Keywords

Disaster; Recovery; Planning; Health promotion