Introduction and BackgroundLandslides vary in size, speed, and destructiveness over several orders of magnitude, ranging from rapid, catastrophic hillslope failures that can wipe out roads and towns instantaneously to slow, persistent mass movements that last over decades or even centuries. The fatalities and property damage that can result from rapid landslides are well known (Fleming & Taylor, 1980;Froude & Petley, 2018). And while the consequences of slow, persistent landslides may not be readily obvious, they nevertheless have a suite of documented impacts ranging from progressive infrastructure damage (

Landslides exhibit motion with a diversity of styles ranging from apparently steady slow sliding to catastrophic failure, with transitions between (Handwerger et al., 2019;Lacroix et al., 2020). Given the obvious similarities between landslides and faults, there have been several efforts to use fault mechanics, and in particular rate-andstate friction (e.g.,