The nation’s space agency is back on the Hawaii island this week to complete a study using radar to measure subtle changes in the landscape of Kilauea Volcano.

The nine-day NASA study began April 4 but was interrupted after several days when one of the antennas for the Uninhabited Aerial Vehicle Synthetic Aperture Radar, or UAVSAR, was not operating correctly, NASA said.

A NASA Gulfstream III jet with specialized instruments arrived from the Dryden Aircraft Operations Facility in Palmdale, Calif., Monday to complete the radar mapping.

The synthetic aperture radar developed by NASA’s Jet Propulsion Laboratory in Pasadena will be used through Tuesday. A technique called interferometric synthetic aperture radar will send pulses of microwave energy from the aircraft to the ground to measure very subtle deformations in Earth’s surface, such as those caused by earthquakes, volcanoes and glacier movements, NASA said.

The latest eruption of Kilauea Volcano took place between March 5 and 11, when a fissure occurred along the east rift zone. Satellite radar imagery recorded the progress of the eruption.

The NASA jet, operating out of Kona Airport, will fly at an altitude of about 41,000 feet. The UAVSAR’s first work over this volcanic region took place in January 2010, when Kilauea was mapped daily for a week. The UAVSAR detected deflation of Kilauea’s caldera over one day, part of a series of deflation/inflation events at Kilauea as magma was pumped into the volcano’s east rift zone.