ESA satellite reveals Yellowstone’s deep secret   The rim of the Yellowstone Caldera.   This image of ground deformation was created using data from several satellite passes from 1996 through 2000. The image shows 125 mm of uplift centred within the northern end of Yellowstone caldera (black dotted line), about 10 km south of Norris. Each full spectrum of colour (from red to purple) represents about 28 mm of uplift. The uplift is approximately 35 km x 40 km in size.   A satellite passes over an area and records data about it. Two or more passes are needed to create the InSAR (Synthetic Aperture Radar Interferometry) images, used to examine changes in ground height. Release date: 9 March 2006