Assessing local impacts of the 1700 CE Cascadia earthquake and tsunami using tree-ring growth histories: a case study in South Beach, Oregon, USA

Robert P. Dziak, Bryan A. Black, Yong Wei, Susan G. Merle

Research output: Contribution to journalArticlepeer-review

Abstract

We present an investigation of the disturbance history of an old-growth Douglas-fir (Pseudotsuga menziesii) stand in South Beach, Oregon, for possible growth changes due to tsunami inundation caused by the 1700 CE Cascadia Subduction Zone (CSZ) earthquake. A high-resolution model of the 1700 tsunami run-up heights at South Beach, assuming an "L"-sized earthquake, is also presented to better estimate the inundation levels several kilometers inland at the old-growth site. This tsunami model indicates the South Beach fir stand would have been subjected to local inundation depths from 0 to 10 m. Growth chronologies collected from the Douglas-fir stand shows that trees experienced a significant growth reductions in the year 1700 relative to nearby Douglas-fir stands, consistent with the tsunami inundation estimates. The ±1-3-year timing of the South Beach disturbances are also consistent with disturbances previously observed at a Washington state coastal forest g1/4220 km to the north. Moreover, the 1700 South Beach growth reductions were not the largest over the >321-year tree chronology at this location, with other disturbances likely caused by climate drivers (e.g., drought or windstorms). Our study represents a first step in using tree growth history to ground truth tsunami inundation models by providing site-specific physical evidence.

Original languageEnglish (US)
Pages (from-to)1971-1982
Number of pages12
JournalNatural Hazards and Earth System Sciences
Volume21
Issue number6
DOIs
StatePublished - Jun 30 2021

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)

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