NASA Maps Ground Changes >From Puerto Rico Quake
Scientists use satellite data to help response agencies identify damaged areas.
Days after a 6.4-magnitude earthquake rocked
Puerto Rico, followed by hundreds of aftershocks, the full extent of damage is
only beginning to be realized.
NASA scientists are using satellite data to
help federal and local agencies identify areas with potential damage. Earthquakes
cause permanent changes to the ground surface. By comparing interferometric
synthetic aperture radar (InSAR) data acquired on Jan. 9, 2020, with data
acquired on Dec. 28, 2019, from the Copernicus Sentinel-1A satellite, the scientists
were able to map where, how much and in what direction those changes occurred.
Managed by the European Space Agency (ESA), the
Copernicus Sentinel-1A satellite was able to see the eastern two-thirds of the
island during the Jan. 9 flyover. On the map, red indicates areas where the
ground was changed, or displaced, with darker shades corresponding to more
significant displacement. The scientists found that the greatest displacement
from the flyover area occurred west of the city of Ponce (identified by the
green star), not far from the quake's offshore epicenter. They recorded up to
5.5 inches (14 centimeters) of ground change there. The ground appeared to
shift downward and slightly to the west.
The quake epicenter and the cluster of quakes
and aftershocks in the region identified by the United States Geological Survey
(shown as orange circles) fall just west of the satellite's Jan. 9 track. Because
of this, scientists also plan to analyze data from Sentinel-1A's forthcoming Jan.
14 flyover, which will include western Puerto Rico.
The NASA Earth Applied Sciences Disasters Program has activated Tier 1 response in support of this disaster and is in
contact with the Federal Emergency Management Agency, the United States
Geological Survey and Health and Human Services (HHS) to provide NASA
Earth-observing data in support of response and recovery efforts. Products in
the process of being produced include Suomi-NPP-based "Black Marble" power
outage maps, damage maps, and landslide maps. A webpage has also been created on the NASA Disasters Mapping Portal to supply
relevant GIS data products.
The map contains modified Copernicus Sentinel data processed by
ESA and analyzed by scientists at NASA's Jet Propulsion Laboratory, and
earthquake location data from the USGS.
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