2002 and 2003 Gravity and GPS observations in Yellowstone's Upper Geyser Basin

Here we present 10 days of continuous relative gravity and global positioning system [GPS] campaign data from 2002 and 5 days of GPS campaign data from 2003 collected in Yellowstone's Upper Geyser Basin. These data confirm the persistence of the crustal deformation first detected in absolute gravity measurements from 2000 and 2001 and GPS observations from 2001 in the Upper Geyser Basin. The magnitude of the oscillatory microgravity fluctuations is on the order of +/- 4-6 microGals, on the timescales of hours to tens of hours. The crustal deformation inferred from the GPS is on the order several cm of vertical motion and is corroborative of the apparent inflation and deflation interpreted from the gravity measurements. The 2002 continuous gravity data provides a higher resolution of the temporal gravity signal with 1 minute averages versus the 1 hour and 15 minute sets from the 2000 and 2001 absolute gravity data. In the 2002 and 2003 campaigns we tried to test the breadth of the crustal deformation signal with spatially broadly distributed GPS campaign measurements. The 2003 GPS campaign sites span the length and the width of the 3.2 km x 0.8 km Upper Geyser Basin.