GRADUATE SEMINAR PRESENTATION

Presented by: Prof. Roland Bürgmann, UC Berkeley

Abstract: In California and around the world, the accumulation of surface water in lakes and reservoirs, groundwater in sedimentary basins, and winter snowpack follow an annual cycle. The surface loads resulting from the seasonal changes in water storage produce elastic deformation of the Earth’s crust and can perturb stresses at depth. Seasonal loading thus provides a natural laboratory to explore the crustal response to a quantifiable transient force. We use vertical GNSS displacement time series, GRACE satellite gravity data and hydrological models to constrain mechanical models of monthly water loading and compute the resulting stress changes on fault planes of small earthquakes. We also consider the seasonal stress changes for tidal, thermal, and atmospheric loading sources with annual periods. In California, we find the hydrological loads are the largest source of seasonal stresses and produce resolvable modulation of micro-seismicity. We also consider case studies in Alaska, East Africa and Taiwan, each exhibiting a somewhat different seismicity response. There is no “earthquake weather”, but through careful mechanical and statistical analyses we can document the modulation of earthquakes by climate processes.

Biography: Roland Bürgmann received his M.S. at the University of Colorado, Boulder in 1989 and his Ph.D. at Stanford University, in 1993. He is currently Professor at the Department of Earth and Planetary Science at UC Berkeley. His research interests are in active tectonics, crustal deformation and lithosphere rheology. He coauthored more than 300 papers in peer-reviewed journals. He is a Fellow of the American Association for the Advancement of Science (AAAS) since 2019, a Fellow of the American Geophysical Union (AGU) since 2013, was the 2013 AGU Birch Lecturer, and received the 2005 Bessel Prize of the Humboldt Foundation. Among other service, Bürgmann currently serves as Chair of the National Earthquake Prediction Evaluation Council (NEPEC); Member of the Advisory Board for COMET (Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics), Leeds UK; Member of the Executive Committee, Miller Institute for Basic Research in Science, Berkeley; Member of the Scientific Earthquake Studies Advisory Committee (SESAC); Member, of the Advisory Committee of the Institute of Earth Sciences, Academia Sinica; Member of the UNAVCO Board of Directors; and Member of the SZ4D Steering Committee.

The Graduate Seminar is mandatory for all ErSE and ERPE students. Please remember to sign the participants list in order to register your attendance.

NOTE to all students: We are back in person, so please attend in person, seminar venue is Building 9, room 2325