a) Google Earth image © 2015 Digital Globe image showing the Pan-American Highway in upper right, and an unpaved road from the highway to a hilly area used by tourists to view the Peruvian Nasca World Heritage Site geoglyphs. b) Calibrated correlation image from NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) overlaid in Google Earth. Black corresponds to decorrelation, typically due to disturbance between the two observations (in March 2013 and March 2015), while grey and light grey correspond to areas with minimal decorrelation. The white line corresponds to 100 meters, North is up. Coordinates are 14.707S, 75.103W.
NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), developed and managed by the Jet Propulsion Laboratory, Pasadena, California, can record changes on the ground beneath the aircraft that occur between multiple flights, which take exactly the same flight path. The instrument is used to monitor how volcanoes, earthquakes, and other natural hazards are changing Earth. Principal investigator Bruce Chapman of JPL noted that UAVSAR is ideally suited for observing the Nasca site because the region has virtually no vegetation and receives no rainfall whatsoever in most years, meaning that natural disturbances are minimal.