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Sedimentary evidence of prehistoric distant-source tsunamis in the Hawaiian Islands

April 29, 2019

Over the past 200 years of written records, the Hawaiian Islands have experienced tens of tsunamis generated by earthquakes in the subduction zones of the Pacific "Ring of Fire" (e.g., Alaska-Aleutian, Kuril-Kamchatka, Chile, and Japan). Mapping and dating anomalous beds of sand and silt deposited by tsunamis in low-lying areas along Pacific coasts, even those distant from subduction zones, is critical for assessing tsunami hazard throughout the Pacific basin. We searched for evidence of tsunami inundation using stratigraphic and sedimentologic analyses of potential tsunami deposits beneath present and former Hawaiian wetlands, coastal lagoons, and river floodplains. Coastal wetland sites on the islands of Hawai΄i, Maui, O΄ahu, and Kaua΄i were selected based on historical tsunami runup, numerical inundation modeling, proximity to sandy source sediments, degree of historical wetland disturbance, and breadth of prior geologic and archaeologic investigations. We interpret sand beds containing marine calcareous sediment within peaty and/or muddy wetland deposits on the north and northeastern shores of Kaua΄i, O΄ahu, and Hawai΄i as tsunami deposits. At some sites, deposits of the 1946 and 1957 Aleutian tsunamis are analogs for deeper, older probable tsunami deposits. Radiocarbon-based age models date sand beds from three sites to ~700-500 cal yr B.P., which overlaps ages for tsunami deposits in the eastern Aleutian Islands that record a local subduction zone earthquake (Witter et al., 2016; Witter et al., 2018). The overlapping modeled ages for tsunami deposits at our sites support a plausible correlation with an eastern Aleutian earthquake source for a large prehistoric tsunami in the Hawaiian Islands.

Publication Year 2020
Title Sedimentary evidence of prehistoric distant-source tsunamis in the Hawaiian Islands
DOI 10.1111/sed.12623
Authors SeanPaul La Selle, Bruce M. Richmond, Bruce E. Jaffe, Alan Nelson, Frances Griswold, Maria E.M. Arcos, Catherine Chague, James M. Bishop, Piero Bellanova, Haunani H. Kane, Brent D. Lunghino, Guy R. Gelfenbaum
Publication Type Article
Publication Subtype Journal Article
Series Title Sedimentology
Index ID 70204069
Record Source USGS Publications Warehouse
USGS Organization Coastal and Marine Geology Program; Geologic Hazards Science Center; Pacific Coastal and Marine Science Center