EEPS Colloquium: Adam Forte

Does It All Average Out? Impacts of Short-Term Variability in Climate and Tectonics on Long-Term Topography

Topography represents a rich archive of both the hydroclimatic and tectonic forces that shape it, but we often consider extremely simplified versions of these drivers when interpreting or numerically simulating topography. In detail, many typically assume that short-term spatiotemporal variability effectively “averages out” to a mean or representative value and that the variability is either not important to represent in process models or not interpretable from landscapes. Work over the last two decades have challenged this assumption for erosional processes, showing that temporal variability in stream flow, when considered in the context of erosion thresholds, makes fundamentally different predictions for the evolution of topography than an assumption of a representative discharge. Here I build on this concept by considering the importance of spatiotemporal variability in both hydroclimate and tectonics, in the form of discrete runoff events and variable individual earthquake sequences, in building high relief topography. In both cases, I show that short-term variability on daily to decadal scales in climate and tectonics fundamentally alter topography developed over geologically relevant timescales in ways that are not captured by assuming simple, representative forcing.

Host: Claire Masteller

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