This UAVSAR interferogram shows active volcano Mount St. Helens (left) and dormant volcano Mount Adams, both in Washington state. The sensor collected data for this image during flights in July 2009 and August 2010 to compute the surface deformation that could indicate activity in the volcanoes' magma. No deformation was evident during this period. (NASA image) › View Larger Image
NASA scientists periodically monitor subtle changes in volcanic activity with the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) carried by a modified NASA C-20A (G-III) aircraft. This month the specialized NASA Airborne Science aircraft, with the UAVSAR installed in a pod under the plane's fuselage, deploys to Alaska and Japan to continue a study of active volcanoes.
Developed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., the UAVSAR uses a technique called interferometry to detect and measure very subtle deformations in Earth's surface.
NASA's C-20A (G-III) banks over Edwards Air Force Base, Calif., carrying the UAVSAR underbelly pod, in preparation for studying U.S. and international volcanoes. (NASA / Lori Losey) › View Larger Image This study builds on UAVSAR research of U.S. West Coast and Hawaiian volcanoes acquired from 2009 through 2011 and additional observations of Central and South American volcanoes gathered in 2010 and 2011.
The deployment of NASA's C-20A (G-III) began Oct. 2 when the aircraft departed NASA's Dryden Aircraft Operations Facility in Palmdale, Calif., imaging volcanoes in the Western United States en route to Joint Base Lewis-McChord in Tacoma, Wash. After refueling, the aircraft will travel on to Joint Base Elmendorf-Richardson near Anchorage, Alaska.
The sensor will image volcanoes in Alaska, including those in the Aleutian Islands, before arriving at Yokota Air Force Base near Tokyo, Japan. Yokota is the staging location for science missions to collect data about volcanoes on several islands in Japan that pose a hazard to nearby populations. On its return, the aircraft will repeat the route, acquiring data from the opposite viewing direction, before arriving back at its base in Palmdale Oct. 11.
The aircraft features a high-precision autopilot designed and developed by engineers at NASA's Dryden Flight Research Center. The Precision Platform Autopilot guides the aircraft using a kinematic differential Global Positioning System developed by JPL and the aircraft's inertial navigation system to enable it to fly repeat paths to an accuracy of 15 feet or less. With the precision autopilot engaged, the synthetic aperture radar is able to acquire repeat-pass data that can measure land-surface changes within centimeters.
UAVSAR provides a measurement system that complements satellite-based observations by providing rapid revisits and imaging of active volcanoes to better understand their deformation prior to, during or after an eruption.
In addition to the NASA study of volcanoes, the UAVSAR team is working with Japan Aerospace Exploration Agency scientists to define cross-calibration sites, including flight lines over disaster and forested areas, between the UAVSAR and the PISAR-L2 airborne radars.