TY - JOUR
T1 - Increased flood exposure in the Pacific Northwest following earthquake-driven subsidence and sea-level rise
AU - Dura, Tina
AU - Chilton, William
AU - Small, David
AU - Garner, Andra J.
AU - Hawkes, Andrea
AU - Melgar, Diego
AU - Engelhart, Simon E.
AU - Staisch, Lydia M.
AU - Witter, Robert C.
AU - Nelson, Alan R.
AU - Kelsey, Harvey M.
AU - Allan, Jonathan C.
AU - Bruce, David
AU - DePaolis, Jessica
AU - Priddy, Michael
AU - Briggs, Richard W.
AU - Weiss, Robert
AU - La Selle, Sean Paul
AU - Willis, Michael
AU - Horton, Benjamin P.
PY - 2025/5/6
Y1 - 2025/5/6
N2 - 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 km2 (low), 160 km2 (medium), or 300 km2 (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 km2 (low), 240 km2 (medium), or 370 km2 (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.
AB - 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 km2 (low), 160 km2 (medium), or 300 km2 (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 km2 (low), 240 km2 (medium), or 370 km2 (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.
KW - coastal subsidence
KW - compound hazards
KW - earthquake hazards
KW - sea-level rise
KW - subduction zone hazards
UR - http://www.scopus.com/inward/record.url?scp=105004337781&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=105004337781&partnerID=8YFLogxK
U2 - 10.1073/pnas.2424659122
DO - 10.1073/pnas.2424659122
M3 - Article
C2 - 40294262
AN - SCOPUS:105004337781
SN - 0027-8424
VL - 122
SP - e2424659122
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 18
ER -