The Advanced Rapid Imaging and Analysis (ARIA) team at NASA's Jet Propulsion Laboratory in Pasadena, California, and Caltech, also in Pasadena, created this Damage Proxy Map (DPM) depicting areas in Central Sulawesi, Indonesia, including the city of Palu, that are likely damaged (shown by red and yellow pixels) as a result of the magnitude 7.5 September 28, 2018 earthquake. The map is derived from synthetic aperture radar (SAR) images from the ALOS-2 satellite, operated by Japan Aerospace Exploration Agency (JAXA). The images were taken before (Aug. 8, 2018) and after (Oct. 3, 2018) the earthquake.
The map covers an area of 42 by 44 miles (67 by 70 kilometers), shown by the large red polygon. Each pixel measures about 33 yards (30 meters) across. The color variation from yellow to red indicates increasingly more significant ground surface change. Preliminary validation was done in collaboration with the Earth Observatory of Singapore by comparing with local media information and photos. This damage proxy map should be used as guidance to identify damaged areas, and may be less reliable over vegetated areas. For example, the scattered single colored pixels over vegetated areas may be false positives, and the lack of colored pixels over vegetated areas does not necessarily mean no damage.
The DPM was created by the NASA-JPL/Caltech ARIA team, and the ALOS-2 data were provided by JAXA. The Earth Observatory of Singapore coordinated with the Sentinel Asia to timely task the ALOS-2 satellite. The algorithm development was carried out at JPL under a contract with NASA.
For more information about ARIA, visit http://aria.jpl.nasa.gov.