Cataclysmic Erasure of Mountain Topography and Major Unrealized Seismic Hazards in the Northern Basin and Range

Denudation of mountain topography is classically attributed to surface processes such as erosion and mass wasting or to dynamic effects such as gravitational collapse and rarely have other removal mechanisms been considered. Although denduation rates as high as 10 cm yr-1 have been observed in tectonically active mountain belts, these rates are unlikely to be sustained as elevation gradients are diminished over the lifespan of an orogenic system, and thus they require >10-100 Myr to completely denude tectonically generated relief. However, in the northernmost Basin and Range of North America the low-relief track of the Yellowstone hotspot apparently ‘truncates’ multiple high-relief mountain ranges and the seismogenically active normal faults that produced these uplifts. This leads to the idea that migration of the hotspot has ‘erased’ the continental topographic divide that otherwise extends from northern Mexico to Canada. In this scenario, major mountain belts would be completely and cataclysmically removed in