Risk assessment of a tsunamigenic rockslide at Åknes

Abstract

This paper introduces the application of a simple and practical method for estimating the risk associated with a potential tsunamigenic rockslide, by assessing quantitatively hazard, vulnerability, and elements at risk. The proposed method introduces empirical relations between the risk components and illustrates the uncertainty propagation through the steps in the risk analysis. A case study is presented, showing the applicability of the method for estimating the risk associated with the tsunamigenic Å knes rockslope in Stranda municipality in western Norway. Results show, preliminary risk estimates that will be of significant value for future policy and decision making.

Probabilistic calibration of a damage rock mechanics model

“…The Bayesian approach has been used to calibrate numerous geomechanical models such as liquefaction (Cetin et al, 2002), snow avalanches (Gauer et al, 2009), landslides (Ranalli et al, 2009(Ranalli et al, , 2013, tsunamigenic rockslides (Eidsvig et al, 2009), mudslides (Medina-Cetina & Cepeda, 2012, soils' constitutive models (Medina-Cetina, 2006;Medina-Cetina & Rechenmacher, 2009) and foundations (Yu et al, 2011;Briaud et al, 2011) and, more recently, multi-physics geophysical inversions (MedinaCetina et al, 2013) and probabilistic damage prediction in rocks (Arson & Medina-Cetina, 2013). However, the Bayesian paradigm has never been used to maximise damage model performance.…”

Space-Borne and Ground-Based InSAR Data Integration: The Åknes Test Site

“…It is considered one of the most hazardous rockslide areas in Norway [44], including about 50 million m 3 of rock [26], characterized by continuous creep. The location of the landslide body, which develops above the fjord and near several communities, makes the surrounding area exposed to a high level of risk, mainly in terms of a possible tsunami, induced by the collapse of rock material into the fjord [45,46]. The area also represents one of Norway's most visited tourist attractions, thanks to the natural beauty of the mentioned fjord (the nearby Geirangerfjord is listed on UNESCO's World heritage list).…”

Multi-hazard Approaches to Civil Infrastructure Engineering

“…What makes the BN approach unique is that different groups of independent experts at NGI working on (Eidsvig et al 2011) the modeling of rockslides, tsunami, and risk quantification were asked to propose informed belief measures for defining probability distributions to be assigned to the risk factors (Eq. 19.1) via a Markov conditioning network scheme depicting causeeffect relationships, resulting on an improved representation of the likelihood of occurrence of each of the risk factors taking place in the risk assessment process.…”

“…The objective of the NGI workshop was to identify the Åknes' hazard (probability of the coupling of multiple threats), the region vulnerability (probability of impacting certain elements at risk conditioned on specific coupling of threats' intensities), and the elements at risk in Storfjorden (human life and material damage). This work follows a reference paper stemmed from the NGI workshop and published by the same authors of this paper, where a "classical" risk assessment approach was initially introduced (Eidsvig et al 2011). However, for the easiness of the comparison analysis with the proposed Bayesian risk assessment approach presented in this paper, a summary of the reference paper is being reproduced here.…”