A first dendrogeomorphologic approach of snow avalanche magnitude-frequency in Northern Iceland

作者：Decaulne Armelle^*; Eggertsson Olafur; Saemundsson Porsteinn

来源：Geomorphology, 2012, 167: 35-44.

DOI：10.1016/j.geomorph.2011.11.017

• Dendrogeomorphology
• European White Birch (Betula pubescens Ehrh.)
• Snow avalanche
• Iceland

The paper examines the potential of dendrogeomorphic analyses to deliver a one-year resolution chronology of snow-avalanche winters in Northern Iceland, at the scale of a colluvial cone covered with European White Birch trees and shrubs (Betula pubescens Ehrh.). Reconstruction of the avalanche history is performed using tree-ring analyses. Determination of the most reliable growth disturbance (class 1 of growth eccentricity) and applying a tempering index value with threshold 10% of trees responding in the same year and at least two trees affected, avalanche-activity years are highlighted, resulting in 52 avalanche winters. Amongst those, 5 winters have activity index over 40%, indicating major years. Calculation of frequency of similar growth disturbances at each tree provides a return period ranging from 4.2 to 19 years. Inferred spatial extent of snow-avalanche events induces flow-like snow avalanches with limited extent around the tree-less parts of the cone with a return period under 6 years; the cone is totally covered and the distal tree-limit over-passed with a return period of 15-20 years.

• 出版日期2012-9-15