Numerical simulation of the landslide‐generated tsunami in Kitimat Arm, British Columbia, Canada, 27 April 1975

Abstract

[1] It remains challenging to predict and estimate potential damage from tsunamis using computer models. One of the approaches to validate models is to compare their results with site observations. We carried out numerical modeling for both the underwater landslide and the associated tsunami that occurred near Kitimat, British Columbia, Canada on 27 April 1975. A few observations of high water marks along the coastline indicated 8.2 m tsunami waves. Previous survey results of the seafloor showed that a landslide traveled about 5 km down the axis of the fjord from its source areas on the sidewall of the fjord, near the head of the inlet, and on the lower Kitimat River delta. We modeled the subaqueous slope failure as a Bingham visco-plastic fluid (debris flow) based on previous geotechnical investigations at the site, and numerically solved the landslidegenerated tsunami wave and debris flow equations using a finite-volume Godunov-type scheme. This method resolves abrupt wave and landslide front interactions and remains oscillation-free. The computed motion of the debris flow is generally consistent with observations; simulations indicate that the failure propagated approximately 4.5 km down the fjord axis from its inception point. We have found that computed amplitudes for the tsunami wave crest at the coast of Kitimat Arm were between 6 and 11 m; these values are somewhat higher than previous simplistic solitary wave theory estimates of 6.3 m and observations of 8.2 m.Citation: Skvortsov, A., and B. Bornhold (2007), Numerical simulation of the landslide-generated tsunami in Kitimat Arm, British

Tsunami inundation maps for Juneau, Alaska

“…The viscous deformable slide model was found to predict somewhat lower wave heights than the solid slide model. The solid slide also produced results comparable to the viscoplastic slide model developed by Skvortsov and Bornhold (2007). Similarly, Ataie-Ashtiani and Najafi-Jilani (2008) and Najafi-Jilani and Ataie-Ashtiani (2008) experimentally showed that granular slides had a maximum amplitude up to 15 percent smaller than that of the equivalent rigid slide.…”

“…In this particular event, the M w 7.1 earthquake triggered an underwater slump that produced a tsunami with a 15 m local inundation, killing almost 2,200 people (Tappin and others, 2008). After the PNG tragedy, in order to minimize future losses, a number of models to simulate water dynamics due to submarine landslides have been developed (e.g., Fine and others, 1998;Grilli and Watts, 1999;Watts and others, 2003;Lynett and Liu, 2002;Skvortsov and Bornhold, 2007;Løvholt and others, 2008;Weiss and Wünnermann, 2009;Horrillo and others, 2013;Ma and others, 2013;George and Iverson, 2014).…”

Direct monitoring of active geohazards: emerging geophysical tools for deep‐water assessments

“…Smaller landslides also pose a credible threat to seafloor infrastructure and coastal communities, particularly as they occur more frequently. Landslide volumes of <<0.1 km 3 triggered tsunamis offshore Nice (Dan, Sultan and Savoye ) and British Columbia (Skvortsov and Bornhold ) and resulted in landward retrogression leading to loss of life in Norway (Vardy et al . ).…”

“…Smaller landslides also pose a credible threat to seafloor infrastructure and coastal communities, particularly as they occur more frequently. Landslide volumes of <<0.1 km 3 triggered tsunamis offshore Nice (Dan, Sultan and Savoye 2007) and British Columbia (Skvortsov and Bornhold 2007) and resulted in landward retrogression leading to loss of life in Norway (Vardy et al 2012). Even smaller failures of only 1.5-to 2-m thickness ruptured utility pipelines at several locations in Lake Mjøsa, Norway, causing damage of approximately $6.5 million (Forsberg, Heyerdahl and Solheim 2016).…”

A nested-grid Boussinesq-type approach to modelling dispersive propagation and runup of landslide-generated tsunamis

“…Savage and Hutter, 1989;LeBlond, 1992, 1993;Rabinovich et al, 1999;Imran et al, 2001;Skvortsov and Bornhold, 2007), or a flow with strong turbulence and vorticity which can be predicted through the Navier-Stokes theory (e.g. Gisler et al, 2006;Wünnemann et al, 2006;Abadie et al, 2010).…”