New insights into the 21 November 2000 tsunami in West Greenland from analyses of the tree-ring structure of Salix glauca

We test the application of dendrochronological methods for dating and assessing the environmental impacts of tsunamis in polar regions, using an example of the 21 November 2000 landslide-generated tsunami in Vaigat Strait (Sullorsuaq Strait), West Greenland. The studied tsunami inundated a c. 130 m-wide coastal plain with seawater, caused erosion of beaches and top soil and covered the area with an up to 35 cm-thick layer of tsunami deposits composed of sand and gravel. Samples of living shrub, Salix glauca (greyleaf willow) were collected in 2012 from tsunami-flooded and non-flooded sites. The tree-ring analyses reveal unambiguously that the tsunami-impacted area was immediately colonized during the following summer by rapidly growing shrubs, whilst one of our control site specimens records evidence for damage that dates to the time of the tsunami. This demonstrates the potential for dendrochronological methods to act as a precise tool for the dating of Arctic paleotsunamis, as well as rapid post-tsunami ecosystem recovery. The reference site shrubs were likely damaged by solifluction in the autumn 2000 AD that was triggered by high seasonal rainfall, which was itself a probable contributory factor to the tsunami-generating landslide.