2025-2026 Lecturer: David Mohrig

David Mohrig

Jackson School of Geosciences, University of Texas at Austin

Biography

Dr. David Mohrig holds the Peter T. Flawn Centennial Chair in Geology at The University of Texas at Austin, where he has been on the faculty since 2006, after spending five years on the MIT faculty and another five years as an industry geoscientist. 
David's research focuses on the flow of solids across planetary surfaces and the transport processes modulating this flow, leading to erosion and sedimentation that evolves terrestrial, submarine, and extraterrestrial landscapes. He studies topography generated at the interface between a static bed and a moving fluid at very short to very long time and space scales, with particular emphasis on processes controlling channel and coastline formation. He has experience leading large integrated teams of geoscientists, engineers, oceanographers, ecologists, and economists studying land building and loss in the Mississippi Delta, as well as using successive high-resolution topographic surveys to study shoreline change associated with tropical cyclones and other storms. Recent work highlights the responses of coastal rivers and deltas, barrier islands, and coastal plains to both naturally occurring and anthropogenic change.
David received his B.A. from Pomona College, and his M.S. and Ph.D. degrees from the University of Washington, Seattle. He was awarded the 2019 Francis J. Pettijohn Medal for Sedimentology by the Society for Sedimentary Geology (SEPM) and the 2021 G.K. Gilbert Award in Surface Processes by the American Geophysical Union. His research is inspired by the many undergraduate and graduate students he has collaborated with throughout the years. 


Abstract: Construction and Destruction of Coastal Zones in our Changing Environment

Low-relief coastal zones host an outsized fraction of Earth’s human population and its critical infrastructure. On top of this, these coastal zones and connected shorelines respond sensitively to both anthropogenic and natural environmental change. Two factors affecting these landscapes and shorelines are sea-level rise and land-surface subsidence. The consequences of both will be discussed with a particular emphasis placed on recent advances made in measuring subsidence, as well as understanding the unanticipated persistence of accelerated subsidence at many locations following extraction of subsurface pore fluid. While sea-level change and subsidence play an important role in modulating coastal-zone elevations, the patterns and timescales of landscape evolution within these coastal zones are largely set by the creation and evolution of channels and channel networks that control patterns of sediment deposition and erosion that either generate topography or remove land. This seminar will also examine the properties of two styles of conduits routing sediment across these surfaces: (1) channel networks within coastal drainage basins and (2) overwash/outwash channels cut by landward or seaward-directed storm surge. Understanding their structures is important when interpreting the long-term development of these coastal systems and when assessing risks in coastal zones that are vulnerable to the combined effects of coastal, riverine, and pluvial flooding.