Abstract. We present a spatially focused investigation of the disturbance history of an old-growth Douglass fir stand in South Beach, Oregon for possible growth effects due to tsunami inundation caused by the A.D. 1700 Cascadia subduction zone 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 0–10 m. Growth chronologies collected from the fir stand shows several trees experienced significant growth reductions before, during and several years after 1700, 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 ~220 km to the north. Additional comparison of the South Beach chronologies with regional chronologies across Oregon indicates the South Beach stand growth was significantly and unusually lower in 1700. Moreover, the 1700 South Beach growth reductions were not the largest over the 110-year tree chronology at this location. with other disturbances likely caused by other 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.

中文翻译：

---

利用树木年轮的生长历史评估公元1700年卡斯卡迪亚地震和海啸对当地的影响：以美国俄勒冈州南海滩为例

摘要。我们对俄勒冈州南海滩的老道格拉斯冷杉林分的扰动历史进行了空间集中的调查，以了解由于公元1700年卡斯卡迪亚俯冲带地震引起的海啸淹没而可能产生的增长效应。假设L值为1，南海滩1700海啸上升高度的高分辨率模型还提出了一次大地震，以更好地估计旧站点内陆几公里处的淹没程度。该海啸模型表明，南滩冷杉林分将遭受0-10 m的局部淹没深度。从冷杉林分收集的生长年表显示，在1700年之前，期间和之后的几年中，几棵树木的生长显着减少，这与海啸淹没的估计一致。南海滩扰动的+/- 1-3年时间也与先前在北约220公里的华盛顿州沿海森林中观察到的扰动一致。将南海滩的时间顺序与俄勒冈州各地域的时间顺序进行的进一步比较表明，南海滩的林分增长在1700年显着且异常低。在该地点的110年树年中，1700年南滩的增长减幅并不是最大的。以及其他气候驱动因素可能引起的其他干扰（例如干旱或暴风雨）。我们的研究代表了通过使用树木的生长史来提供真实的海啸淹没模型，这是迈出的第一步。