Tsunami generation by potential, partially submerged rockslides in an abandoned open-pit mine: the case of Black Lake, Quebec, Canada

Abstract

Abstract:The Black Lake rockslide is located on the east wall of an open pit mine initially operated by LAB Chrysotile near Thetford Mines, Québec. Movements were observed in July 2012 when a volume of 20 M m³ was mobilized, destroying a large portion of the Highway 112. Mining operations ceased in 2012, causing the complete shutdown of the pumping system whose goal was to prevent the rise of water level in the pit. As the water level increases in the pit, it is essential to determine the tsunamis generated by possible partially submerged rockslides and to understand their potential impacts. A series of possible scenarios have been analysed with regard to velocity and acceleration of the potential rockslide as well as the corresponding wave generation and inundation. Results from the simulation shows that when the factor of safety of the global slope is less than unity, inundation would not reach the potentially vulnerable infrastructures. Maximum wave height will vary as a function of the filling of the lake, and the lower wave height relative to water depth will happen when the lake will be completely filled. Mots-clés :Tsunami généré par un glissement de terrain, glissement partiellement submergé, modélisation numérique, mine à ciel ouvert, glissement rocheux actif.

Three‐Dimensional Physical Modeling of Tsunamis Generated by Partially Submerged Landslides

“…However, they still take place, as demonstrated by the 2010 Haiti Earthquake, 2018 Sunda Strait Tsunami and 2018 Palu Tsunami. In addition, the potential hazard posed by partially submerged landslide‐tsunamis have been noticed and assessed in La Yesca reservoir, Mexico (Gómez et al., 2016) and Black Lake, Canada (Leblanc et al., 2018). While a number of predictive equations have been proposed for subaerial and submarine landslide‐tsunamis, the applicability of these equations to a partially submerged type is questionable (as the wave generation mechanism is not completely identical).…”