Natural Hazards

, Volume 72, Issue 2, pp 849–870

Tsunami impact to Washington and northern Oregon from segment ruptures on the southern Cascadia subduction zone

  • George R. Priest
  • Yinglong Zhang
  • Robert C. Witter
  • Kelin Wang
  • Chris Goldfinger
  • Laura Stimely
Original Paper

DOI: 10.1007/s11069-014-1041-7

Cite this article as:
Priest, G.R., Zhang, Y., Witter, R.C. et al. Nat Hazards (2014) 72: 849. doi:10.1007/s11069-014-1041-7

Abstract

This paper explores the size and arrival of tsunamis in Oregon and Washington from the most likely partial ruptures of the Cascadia subduction zone (CSZ) in order to determine (1) how quickly tsunami height declines away from sources, (2) evacuation time before significant inundation, and (3) extent of felt shaking that would trigger evacuation. According to interpretations of offshore turbidite deposits, the most frequent partial ruptures are of the southern CSZ. Combined recurrence of ruptures extending ~490 km from Cape Mendocino, California, to Waldport, Oregon (segment C) and ~320 km from Cape Mendocino to Cape Blanco, Oregon (segment D), is ~530 years. This recurrence is similar to frequency of full-margin ruptures on the CSZ inferred from paleoseismic data and to frequency of the largest distant tsunami sources threatening Washington and Oregon, ~Mw 9.2 earthquakes from the Gulf of Alaska. Simulated segment C and D ruptures produce relatively low-amplitude tsunamis north of source areas, even for extreme (20 m) peak slip on segment C. More than ~70 km north of segments C and D, the first tsunami arrival at the 10-m water depth has an amplitude of <1.9 m. The largest waves are trapped edge waves with amplitude ≤4.2 m that arrive ≥2 h after the earthquake. MM V–VI shaking could trigger evacuation of educated populaces as far north as Newport, Oregon for segment D events and Grays Harbor, Washington for segment C events. The NOAA and local warning systems will be the only warning at greater distances from sources.

Keywords

Tsunami Cascadia Segment ruptures Warning Earthquake 

Abbreviations

DOGAMI

Oregon Department of Geology and Mineral Industries

CSZ

Cascadia subduction zone

MHHW

Mean higher high water

NOAA

National Oceanic and Atmospheric Administration

Supplementary material

11069_2014_1041_MOESM1_ESM.xlsx (4.6 mb)
Supplementary material 1 (XLSX 4735 kb)
11069_2014_1041_MOESM2_ESM.xlsx (4 mb)
Supplementary material 2 (XLSX 4098 kb)

Copyright information

© US Government 2014

Authors and Affiliations

  • George R. Priest
    • 1
  • Yinglong Zhang
    • 2
  • Robert C. Witter
    • 3
  • Kelin Wang
    • 4
  • Chris Goldfinger
    • 5
  • Laura Stimely
    • 1
  1. 1.Oregon Department of Geology and Mineral IndustriesNewport Coastal Field OfficeNewportUSA
  2. 2.Center for Coastal Resources ManagementVirginia Institute of Marine ScienceGloucester PointUSA
  3. 3.U.S. Geological SurveyAlaska Science CenterAnchorageUSA
  4. 4.Geological Survey of CanadaPacific Geoscience CentreSidneyCanada
  5. 5.Oregon State UniversityCorvallisUSA

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