2019 11 15 Jeff Freymueller, Michigan State University

Speaker: Jeff Freymueller, Endowed Chair for Geology of the Solid Earth, Dept. of Earth & Environmental Sciences, Michigan State University Host: Gail Christensen Title: Separating Long-term Tectonic Motions, Surface Loading and Other Sources of Earth Deformation Abstract: Plate tectonics is driven by forces internal to the solidEarth, and measuring tectonic motions has been a fruitful focus for geodesy for the last few decades. However, geodetic observations depend not only on long-term tectonic motions, but also on elastic and viscoelastic effects of locked faults and the earthquake cycle. In addition, motions that ultimately result from surface loading (including glacial isostatic adjustment, GIA) also contribute to the measurements, both directly and in subtle indirect ways. As our field moves increasingly to the study of smaller amplitude steady motions and transient, time-dependent fault deformation, identifying these non-tectonic contributions becomes increasingly important. In this talk, I will take a tour around the North American continent to illustrate how these sources of Earth deformation can be separated, and how the continental-scale impact of GIA impacts estimates our estimates of tectonics.