Event

The Department of Earth & Environmental Science

University of Pennsylvania

Invites you to attend a EES Seminar Series

Friday, January 19th - 3:00 PM

"Fires, Ferns and Squirrels: Controls on Nonlocal Hillslope Sediment Transport"

Sediment transport in steep landscapes is often driven by stochastic disturbances that can send loose particles rolling and bouncing long distances downhill over uneven terrain. These long-distance or “nonlocal” particle fluxes are an important component of long-term steepland sediment budgets and landscape dynamics. They can also contribute to dramatically elevated erosion rates and hazards like debris flows after wildfires, as the incineration of vegetation releases trapped sediment and removes obstacles to particle motion. However, nonlocal sediment fluxes are poorly represented by the diffusive hillslope framework commonly used to model soil creep, which relies on empirical parameters calibrated from long-term average erosion rates. Predicting how landscapes will respond to perturbation, either at the event scale or with long-term shifts in vegetation communities and rates of soil production or disturbance due to climate change, requires flexible models that can account for the effects of these variables on transport mechanics. In this talk, I will discuss recent advancements and ongoing efforts toward the development of a probabilistic, particle-based model capable of accounting for mechanistically distinct sediment entrainment and disentrainment processes. Post-wildfire field studies in Oregon and California demonstrate that this model effectively captures the influence of particle size, surface slope and vegetative roughness on particle motion. Our results provide new insights on the roles of biotic disturbance and vegetation regrowth in post-fire steepland sediment dynamics.

Dr. Danica Roth

Assistant Professor

Department of Geology and Geological Engineering 

Colorado School of Mines

Danica Roth is an assistant professor in the Department of Geology and Geological Engineering at the Colorado School of Mines. Prior to Mines, she completed an NSF postdoctoral fellowship at the University of Oregon, a PhD in earth science at UC Santa Cruz and undergraduate degrees in physics and astronomy at UC Berkeley. Danica’s research interests center on understanding the coupling of surface processes with regional variables such as climate, biology and anthropogenic influences in order to better relate process mechanics to landscape form and evolution across scales. Common themes in her work include examining feedbacks and morphodynamics in complex Earth surface systems, and linking empirical observations, experiments, and analytical and geophysical techniques to the development of physically-based theory.