Increased flood exposure in the Pacific Northwest following earthquake-driven subsidence and sea-level rise

• 成果类型: Article
• 署名作者: Dura, Tina; Chilton, William; Small, David; Garner, Andra J.; Hawkes, Andrea; Melgar, Diego; Engelhart, Simon E.; Staisch, Lydia M.; Witter, Robert C.; Nelson, Alan R.; Kelsey, Harvey M.; Allan, Jonathan C.; Bruce, David; Depaolis, Jessica; Priddy, Michael; Briggs, Richard W.; Weiss, Robert; La Selle, Seanpaul; Willis, Michael; Horton, Benjamin P.
• 署名单位: Virginia Polytechnic Institute & State University; University of Oregon; Rowan University; University of North Carolina; University of North Carolina Wilmington; Durham University; United States Department of the Interior; United States Geological Survey; United States Department of the Interior; United States Geological Survey; United States Department of the Interior; United States Geological Survey; California State University System; California State Polytechnic University Pomona; United States Department of the Interior; United States Geological Survey; City University of Hong Kong; Nanyang Technological University; Nanyang Technological University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12461
• DOI: 10.1073/pnas.2424659122
• 发表日期: 2025-05-06
• 关键词: cascadia earthquake; coast; rupture; AREA

摘要

Climate-driven sea-level rise is increasing the frequency of coastal flooding worldwide, exacerbated locally by factors like land subsidence from groundwater and resource extraction. However, a process rarely considered in future sea-level rise scenarios is sudden (over minutes) land subsidence associated with great (>M8) earthquakes, which can exceed 1 m. Along the Washington, Oregon, and northern California coasts, the next great Cascadia subduction zone earthquake could cause up to 2 m of sudden coastal subsidence, dramatically raising sea level, expanding floodplains, and increasing the flood risk to local communities. Here, we quantify the potential expansion of the 1% floodplain (i.e., the area with an annual flood risk of 1%) under low (similar to 0.5 m), medium (similar to 1 m), and high (similar to 2 m) earthquake-driven subsidence scenarios at 24 Cascadia estuaries. If a great earthquake occurred today, floodplains could expand by 90 km(2) (low), 160 km(2) (medium), or 300 km(2) (high subsidence), more than doubling the flooding exposure of residents, structures, and roads under the high subsidence scenario. By 2100, when climate-driven sea-level rise will compound the hazard, a great earthquake could expand floodplains by 170 km(2) (low), 240 km(2) (medium), or 370 km(2) (high subsidence), more than tripling the flooding exposure of residents, structures, and roads under the high subsidence scenario compared to the 2023 floodplain. Our findings can support decision-makers and coastal communities along the Cascadia subduction zone as they prepare for compound hazards from the earthquake cycle and climate-driven sea-level rise and provide critical insights for tectonically active coastlines globally.