A GIS method for assessment of rock slide tsunami hazard in all Norwegian lakes and reservoirs

Abstract

Abstract. An evaluation of rock slide tsunami hazard is applied to all Norwegian lakes larger than 0.1 km 2 based on their topographical setting. The analysis results in a topographic rock slide potential score that indicates the relative hazard in each lake. Even though the score value each lake receives should be interpreted with caution, the distribution of score values shows that we are able to make a clear distinction between lakes with a high vs. lakes with a low hazard. The results also show a clustering of threatened lakes in parts of Western Norway as well as some locations in Northern Norway. This makes the results useful as a tool for focusing further studies on regions or specific lakes that received high scores. The results also show how the method may be used for more detailed analysis of a given lake (or fjord). Maps can be produced that may serve as a guide when carrying out field campaigns or when designing scenarios for numerical simulations of tsunamis in the lake. It should be emphasised that the rock slide potential reported for each lake is based on the topographical setting alone and hence, does not represent the actual probability of rock slides into the lakes. For a given area, more detailed investigations of the geology, triggering factors and frequency of previous rock slide events should be carried out before definite statements about the actual hazard can be made.

Glacial lake outburst flood risk in Himachal Pradesh, India: an integrative and anticipatory approach considering current and future threats

“…Allen et al 2011;Fischer et al 2012), where the overall slope trajectory is[14°(cf. Noetzli et al 2003;Romstad et al 2009). These conservative values are based on ice and/or rock avalanches reported within an extensive global catalogue of events contained in the cited literature, although mass movements from more gentle slopes and obtaining larger run-out distances are possible in exceptional cases.…”

“…The GIS-based approach we used to determine the potential probability of GLOF triggering from any given lake is based on the concept of topographic potential (Romstad et al 2009) which encompasses (a) the potential for rock or ice to detach (parameterised by slope angle) and (b) the potential for the resulting rock and/or ice avalanche to reach a glacial lake (parameterised by the overall trajectory slope or angle of reach) (Fig. 3).…”

Risk assessment of a tsunamigenic rockslide at Åknes

“…6 Rock volume exceedance probability for Storfjorden (from historical data, green dots) and for Å knes (estimates from expert's beliefs, red dots) rockslides are only slightly affected by the ambient water (De Blasio et al 2006;NGU 2008;Romstad et al 2009). The largest scenario starts closer to the fjord, and will not achieve the same high-impact velocity as the ones starting higher up.…”

Morphological signatures of mass wasting and delta processes in a fjord-lake system: insights from Lovatnet, western Norway

“…2, 6). The potential and is still considered tsunamigenic (Romstad et al, 2009). Fortunately, tsunami hazard levels have been reduced due to debris filling the lake below Ramne fjellet, as well as risk levels as settlements have either been abandoned or re-established at higher elevations.…”