Increased flood exposure in the Pacific Northwest following earthquake-driven subsidence and sea-level rise
Year: 2025
Type: article
Abstract: 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 (~0.5 m), medium (~1 m), and high (~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.
Authors: Tina Dura, William Chilton, David Small, Andra J. Garner, Andrea Hawkes, Diego Melgar, Simon E. Engelhart, Lydia M. Staisch, Robert C. Witter, Alan R. Nelson, Harvey M. Kelsey, Jonathan C. Allan, David Bruce, Jessica DePaolis, Michael Priddy, Richard W. Briggs, Robert Weiss, SeanPaul La Selle, Michael Willis, Benjamin P. Horton
Institutions: Virginia Tech, Water Institute, Tanzania, University of Oregon, Rowan University, Durham University, United States Geological Survey, Geology, Minerals, Energy, and Geophysics Science Center, Geology, Energy and Minerals Science Center, U.S. Geological Survey, Alaska Science Center, California State Polytechnic University, Pacific Coastal and Marine Science Center, City University of Hong Kong, Nanyang Technological University, Earth Observatory of Singapore
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
Funders: National Science Foundation, U.S. Department of Defense, U.S. Department of Energy, National Aeronautics and Space Administration, Oak Ridge Associated Universities, National Research Foundation, National Research Foundation Singapore, Ministry of Education, India, Earth Observatory of Singapore, Directorate for Geosciences, U.S. Geological Survey, Oak Ridge Institute for Science and Education, Division of Ocean Sciences, Division of Earth Sciences
Awards: Collaborative Research: Constraining next generation Cascadia earthquake and tsunami hazard scenarios through integration of high-resolution field data and geophysical models, G3327541280, Collaborative Research: Heterogeneous Rupture of Great Cascadia Earthquakes Inferred from Coastal Subsidence Estimates, G533919557, G5340730431, G5782651916, EAR-PF: SPATIAL AND TEMPORAL VARIABILITY OF COSEISMIC SUBSIDENCE ALONG THE CASCADIA SUBDUCTION ZONE, G5953853291, Center Operations: Cascadia Region Earthquake Science Center (CRESCENT), G7014231828, G7558184488, G7619220232, G7955800989, G8570346810
OpenAlex ID: W4409872448