A HISTORY OF GEODESY IN YELLOWSTONE NATIONAL PARK AND THE LEGACY OF ROBERT B. SMITH

A history of geodesy in Yellowstone National Park is encapsulated in the work of Bob Smith at the University of Utah, who with his many students and collaborators has greatly increased the scientific understanding of volcanic processes and made Yellowstone one of the foremost natural geologic laboratories in the world. The first geodetic surveys in Yellowstone were done in 1923 for park road construction. New leveling in the 1970s with Bob Smith as principal investigator revealed that Yellowstone caldera had risen over 70 cm from 1923-1977. UNAVCO was established in 1984 as a consortium of universities to pool resources for the newly emerging GPS technology, and Bob and the University of Utah were early members. The first GPS campaigns in 1987 and 1989 revealed caldera subsidence, demonstrating the dynamic nature of the volcanic system. Further campaigns showed further variability, as deformation changed to uplift at the northwest caldera from 1995-2000. The University of Utah installed the first permanent GPS station in 1996 as part of the Yellowstone Geodynamics project. More stations were installed and recorded short-term transient deformation. These first stations would form the backbone of the larger network that followed. As the EarthScope Plate Boundary Observatory (PBO) was being developed, Bob was one of those who proposed a dense instrument cluster at Yellowstone, including additional permanent GPS stations and borehole strainmeters (BSM). Installation began in 2004, in time to record the 2004 rapid caldera uplift episode, the 2008/2009 Lake earthquake swarm, and most recently the 2014 uplift/subsidence associated with a M4.8 earthquake near Norris Junction. Beyond GPS and leveling, the seismograph network, gravity surveys, and the development of InSAR all contributed to a better understanding of the relationship between volcanic activity, earthquakes, and deformation. All these data are publicly available, and can be downloaded freely online. Seismic data are available from the University of Utah Seismograph Stations and from IRIS. All PBO GPS and BSM data are archived at UNAVCO, and are available in raw and processed formats. InSAR data can be accessed through OpenTopography, as can DEM images of the caldera.