NASA has created a map of areas heavily damaged by the 7.1 magnitude earthquake in Mexico. The map is helping Mexican government and other private agencies in relief and rescue operations. The quake, whose epicenter was in Pueblo, caused enormous loss to life and property.
Damage Proxy Mapping
Scientists at NASA’s Jet Propulsion Laboratory(JPL) and Caltech, both located in Pasadena, California, used before-and-after interferometric synthetic aperture radar ( InSAR)satellite imagery of Mexico, identifying the areas heavily damaged and creating a Damage Proxy map. The images are from Copernicus Sentinel 1-A and Sentinel 1-B satellites that are operated by the European Space Agency.
The radar in the satellite was able to detect the damage caused by the earthquake and its immediate ripples and aftershocks, on the basis of change in the ground surface. Variation of color from yellow to red indicates significant changes in ground and building surfaces. The map covers an area of 109 by 106 miles. A single pixel measures about 33 yards(30 meters).
Processing of the radar data was done by the Advanced Rapid Imaging and Analysis (ARIA) team at JPL and Caltech. ARIA is a NASA funded project that is aimed at providing highly reliable and precise GPS and satellite data to assist local, regional, national and international disaster monitoring communities and relief providing communities.
Utility in relief and rescue operations
NASA Disasters program, a part of its Earth Science Division, collaborates with disaster response agencies at multiple levels, to produce information products using global environmental data with the help of NASA’s fleet of Earth Science and satellites. Teams of earth-observation specialists at NASA give a real-time response to various natural disasters and man-made hazards.
ARIA satellites are capable of rapid assessment of geographic region affected by a disaster, as well as exact imaging of the location where maximum damage took place. The satellite can measure even centimeter level ground movement by seeing through clouds. All this is made possible with the use of satellite imagery.
The Damage Proxy map was validated by comparing it to a crowd-sourced Google map. Sentinel-1 data was accessed through Copernicus Open Access Hub. The image includes Copernicus Sentinel data which is processed by ESA and analyzed by NASA and Caltech teams.