EEPS Colloquium: Will Struble

Assistant Professor Will Struble, Tectonic Geomorphology and Surface Processes at the University of Houston

Landscapes evolve through the interplay of uplift and erosion across a range of spatial and temporal scales, influenced by stochastic earthquake and hydrologic processes that trigger landslides. Along the Cascadia Subduction Zone, great earthquakes (Mw>8) occur approximately every 300-500 years, yet their impact on the landscape has remained unclear. Using dendrochronology of drowned ghost forests, we determined the age of landslide-dammed lakes in western Oregon – often with seasonal accuracy – and observed temporal clustering of landslides corresponding to significant regional flooding events. Intriguingly, no dated landslides align with the last major earthquake, a MW ~9.0 on January 26, 1700, raising questions about mechanisms that may obscure or inhibit coseismic landslides in the landscape.

Over longer timescales, tectonic and climatic processes shape landscape characteristics such as river channel steepness and hilltop convexity. Interpreting these “morphologic proxies” requires a quantitative understanding of where in a landscape specific processes predominate and how they transport sediment and incise bedrock.  Here, I will discuss recent advances in developing an erosion-rate proxy for steep landscapes where debris flows are the dominant incisional and sediment-transport mechanism, including a mathematical framework, or ‘geomorphic process law,’ that links debris-flow processes to steepland form.

Host: Claire Masteller

EEPS colloquia are made possible by the William C. Ferguson Fund