Frictional heating lubrication for submarine landslide

Abstract

Given a large block of fine-grained sediment that overlies a 1° continental slope, if the entire sediment deposit is shaken by an earthquake to slide down the slope with an initial velocity (referred to as "submarine landslide" hereinafter), our block model showed that the whole deposit can continuously slide downslope with the "help" of basal frictional heating. In theory, basal Coulomb friction can generate a thermal internal energy in the basal shear zone of landslides (called "frictional heating"), the increasing temperature activating two mechanisms. One mainly decreases the Terzaghi effective normal stress of the landslides and the other decreases the Coulomb friction coefficient. Combining these two mechanisms can effectively decrease the basal frictional resistance of the landslides increasing the mobility of the landslides on gentle slopes (entitled as "frictional heating lubrication"). As shown in our calculations, frictional heating increases with the increase of the initial downslope velocity but decreases with the increase of the shear zone thickness.

Introduction to the special issue on submarine geohazard records and potential seafloor instability

“…The mechanisms of submarine landslides occurred at a low slope angle (even less than 1°) could be related to gas hydrate dissociation, earthquakes, the presence of weak layers, or the compressibility of sediments (Baraza et al 1999;Kvalstad et al 2005;Hornbach et al 2007;Urlaub et al 2015). Different from the previous studies, Chen et al (2018b) took into account the frictional heating generated by sliding and proposed another possible mechanism of submarine landslide occurs on gentle slope. They incorporated three mechanisms of thermopressurization weaking, shear dilatancy and thermal softening together to evaluate their contributions on the initiation of landslide on gentle slope.…”