Confidence levels for tsunami-inundation limits in northern Oregon inferred from a 10,000-year history of great earthquakes at the Cascadia subduction zone

George R. Priest, Chris Goldfinger, Kelin Wang, Robert C. Witter, Yinglong Zhang, António M. Baptista

Research output: Contribution to journalArticle

34 Scopus citations

Abstract

To explore the local tsunami hazard from the Cascadia subduction zone we (1) evaluate geologically reasonable variability of the earthquake rupture process, (2) specify 25 deterministic earthquake sources, and (3) use resulting vertical coseismic deformations for simulation of tsunami inundation at Cannon Beach, Oregon. Maximum runup was 9-30 m (NAVD88) from earthquakes with slip of ~8-38 m and Mw ~8.3-9.4. Minimum subduction zone slip consistent with three tsunami deposits was 14-15 m. By assigning variable weights to the source scenarios using a logic tree, we derived percentile inundation lines that express the confidence level (percentage) that a Cascadia tsunami will not exceed the line. Ninety-nine percent of Cascadia tsunami variation is covered by runup ≤30 m and 90% ≤16 m with a "preferred" (highest weight) value of ~10 m. A hypothetical maximum-considered distant tsunami had runup of ~11 m, while the historical maximum was ~6.5 m.

Original languageEnglish (US)
Pages (from-to)27-73
Number of pages47
JournalNatural Hazards
Volume54
Issue number1
DOIs
StatePublished - Jan 1 2010

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Keywords

  • Cascadia
  • Deterministic
  • Earthquake
  • Oregon
  • Paleoseismic
  • Tsunami

ASJC Scopus subject areas

  • Water Science and Technology
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)

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