Impacts of the 2007 landslide-generated Tsunami in Chehalis Lake, Canada

Abstract

On 4 December 2007, a 3 Mm3 debris avalanche entered Chehalis Lake, British Columbia, Canada. The resulting tsunami caused extensive shoreline damage as far away as the outlet (7.5 km) and far down lower Chehalis River (>15 km). We documented impacts of the tsunami through a multifaceted investigation that included field surveys and collection and analysis of SONAR data, LiDAR data and high-resolution orthophotographs. Geomorphic impacts included a wide range of erosional and depositional features, many of which provide information on wave energy, direction, run-up and inundation along much of the lakeshore. Our characterization of the geomorphic impacts of the Chehalis Lake event advances understanding of landslide-generated tsunami in several ways: it aids identification of events elsewhere by providing insight into their geomorphic signature; it provides an opportunity to verify hydrodynamic numerical models; and it improves regional understanding of hazard and risk. © Springer-Verlag Berlin Heidelberg 2013.