Meen Chel Jung, Karen Dyson, Marina Alberti, Urban landscape heterogeneity disaggregates the legacy of redlining on land surface temperature, Landscape and Urban Planning, Volume 261, 2025, 105406, ISSN 0169-2046, https://doi.org/10.1016/j.landurbplan.2025.105406.
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Abstract
The lingering effects of redlining are linked to contemporary heat inequities observed across US cities. Residential security maps created by the Home Owners’ Loan Corporation (HOLC) have been widely used to analyze neighborhood-level disparities in land surface temperatures. However, the use of aggregated spatial units often fails to capture internal landscape heterogeneity and the heat vulnerabilities associated with redlining. In this study, we introduced urban landscape heterogeneity by incorporating granular development levels captured at different resolutions within HOLC-graded neighborhoods. This approach combined Landsat-based National Land Cover Database (NLCD) data, Sentinel-based WorldCover land cover data, and HOLC map layers. We examined the role of urban landscape heterogeneity in revealing additional patterns of heat inequities beyond those explained by redlining-based macro spatial units, using grouped boxplots and mixed-effects models across three major cities in the Northeastern US: Boston, Massachusetts; New York, New York; and Philadelphia, Pennsylvania. By accounting for urban landscape heterogeneity, our findings revealed that: (1) the well-documented trend of higher land surface temperatures in lower HOLC grades becomes systematically fragmented, (2) statistical models show improved performance in estimating land surface temperature, and (3) the cooling effect of tree canopy exhibits a varying, non-linear threshold pattern. These results highlight the need to consider micro-scale landscape dimensions to better understand the persistent, unequal distribution of temperatures associated with redlining. Municipal and community-led tree planting initiatives should consider comprehensive landscape characteristics to develop spatially targeted heat mitigation strategies and promote equitable climate outcomes.
Keywords
Redlining; Land cover; Spatial resolution; Land surface temperature; Tree canopy cooling; Heat inequity
Dr. Karen Chen’s recent publication as co-lead author is featured in UW News in a story entitled “Q&A: UW-led research identifies migration, housing quality as risk factors in earthquake deaths.” Dr. Chen is an assistant professor in the department of Urban Design & Planning. Read more here.
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
Assistant Professor Karen Chen is awarded the NASA early career investigator award for the program in earth science. Chen’s project will explore heat impacts on health in urban settings in the Mediterranean. Chen is also affiliated with the Department of Environmental and Occupational Health, and CSDE at UW. Read more here.
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…
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
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.
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.
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…
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]