Details:

Journal Title:
Journal of Geophysical Research: Solid Earth
Personal Author:
Yamazaki, Yoshiki ; Lay, Thorne ; Cheung, Kwok Fai
Yamazaki, Yoshiki ; Lay, Thorne ; Cheung, Kwok Fai Less -
NOAA Program & Office:
NWS (National Weather Service)
Description:
The Kalapana, Hawaii, MW 7.7 earthquake on November 29, 1975 generated a local tsunami with at least 14.3 m runup on the southeast shore of Hawaii Island adjacent to Kilauea Volcano. This was the largest locally generated tsunami since the great 1868 Ka'u earthquake located along-shore to the southwest. Well-recorded tide gauge and runup observations provide a key benchmark for studies of statewide tsunami hazards from actively deforming southeast Hawaii Island. However, the source process of the earthquake remains controversial, with coastal landsliding and/or offshore normal or thrust faulting mechanisms having been proposed to reconcile features of seismic, geodetic, and tsunami observations. We utilize these diverse observations for the 1975 Kalapana earthquake to deduce a compound faulting model that accounts for the overall tsunamigenesis, involving both landslide block faulting along the shore and slip on the island basal décollement. Thrust slip of 4.5–8.0 m on the offshore décollement produces moderate near-field runup but controls the far-field tsunami. The slip distribution implies that residual strain energy was available for the May 4, 2018 MW 7.2 thrust earthquake during the Kilauea-East Rift Zone eruption. Local faulting below land contributes to geodetic and seismic observations, but is non-tsunamigenic and not considered. Slip of 4–10 m on landslide-like faults, which extend from the Hilina Fault Zone scarp to offshore shallowly dipping faults reaching near the seafloor, triples the near-field tsunami runup. This compound model clarifies the roles of the faulting components in assessing tsunami hazards for the Hawaiian Islands.
Keywords:
[+]
Earthquakes Landslides Tsunamis
Source:
Journal of Geophysical Research: Solid Earth, 126(11)
DOI:
https://doi.org/10.1029/2021jb022488
ISSN:
2169-9313;2169-9356;
Format:
PDF
Publisher:
American Geophysical Union (AGU)
Document Type:
Journal Article
Funding:
Grant no. NA19NWS4670012
Place as Subject:
Hawaii
Rights Information:
Other
Compliance:
CHORUS
Main Document Checksum:
[+]
urn:sha256:f793be9560d6aa1fdac7898d0fd9500e20773c35545a69d18ee166a9e6f7a8bd
Download URL:
https://repository.library.noaa.gov/view/noaa/49880/noaa_49880_DS1.pdf
File Type:

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