Map of damage in and around San Juan, Puerto Rico (orange inset box) from Hurricane Maria.
NASA/JPL-Caltech-produced map of damage in and around San Juan, Puerto Rico (orange inset box) from Hurricane Maria, based on ground and building surface changes detected by ESA satellites. Color variations from yellow to red indicate increasingly more significant ground and building surface change. Credit: NASA-JPL/Caltech/ESA/Copernicus/Google
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A NASA-produced map showing areas of eastern Puerto Rico that were likely damaged by Hurricane Maria has been provided to responding agencies, including the Federal Emergency Management Agency (FEMA). The hurricane, a Category 4 storm at landfall on Puerto Rico on Sept. 20, caused widespread damage and numerous casualties on the Caribbean island, an unincorporated U.S. territory with a population of about 3.4 million.

To assist in disaster response efforts, scientists at NASA's Jet Propulsion Laboratory and Caltech, both in Pasadena, California, obtained and used before-and-after interferometric synthetic aperture radar (InSAR) satellite imagery of areas of Eastern Puerto Rico to identify the areas that are likely damaged. The imagery -- acquired before the storm on March 25, 2017 and again one day after landfall on Sept. 21, 2017 -- is from the radar instruments on the Copernicus Sentinel-1 satellites operated by the European Space Agency. The resulting Damage Proxy Map shown here may be viewed and downloaded in full resolution at:

The full map data files may be downloaded at:

The views indicate the extent of likely damage caused by the hurricane, based on changes to the ground surface detected by radar. The color variations from yellow to red indicate increasingly more significant ground and building surface change. The map is used as guidance to identify potentially damaged areas and may be less reliable over vegetated and flooded areas. The map covers the area within the large red polygon in the figure, which is 105 by 60 miles (169 by 96 kilometers) in extent. The inset, denoted by the orange rectangle, highlights damage in and around the capital city of San Juan. Each pixel in the map measures about 98 feet (30 meters) across.

NASA delivered the map to responding agencies, including FEMA, on Sept. 22, 2017. FEMA combined the map with building infrastructure data to estimate a damage density map, which was sent to its Urban Search and Rescue teams in the field in Puerto Rico.

The radar data were processed by the Advanced Rapid Imaging and Analysis (ARIA) team at JPL and Caltech. ARIA is a NASA-funded project that is building an automated system for demonstrating the ability to rapidly and reliably provide GPS and radar satellite data to support local, national and international hazard-monitoring and response communities. InSAR can "see" through clouds and is sensitive to changes in the roughness of the ground or building surfaces.

Using space-based radar imagery of disasters, ARIA data products can aid responders in making rapid assessments of the geographic region affected by a disaster, as well as detailed imaging of locations where damage occurred.

Preliminary validation of the Puerto Rico Hurricane Maria Damage Proxy Map was done by comparing it to anecdotal reports of damage. Sentinel-1 data were accessed through the Copernicus Open Access Hub. The image contains modified Copernicus Sentinel data (2017), processed by ESA and analyzed by the NASA-JPL/Caltech ARIA team.

The ARIA team expects to produce another Damage Proxy Map for western Puerto Rico this week, following acquisition of additional Copernicus Sentinel satellite data.

This analysis was supported by the NASA Disasters Program, part of the Earth Science Division in the Science Mission Directorate. The program works with international, regional and local disaster response agencies to produce critical information products using global environmental data from NASA's fleet of Earth science satellites and other airborne and space-based assets, including data from other international space agencies. Dedicated teams of Earth-observation disaster specialists at NASA centers mobilize to respond in real-time to a wide range of natural hazards and human-produced events.

For more information about ARIA, visit:

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Alan Buis
Jet Propulsion Laboratory, Pasadena, Calif.