The Caribbean island of Puerto Rico experienced over 950 earthquakes in less than two weeks of the new year, 2020. Many were too weak to be felt, but more than 500 were of magnitude 2 on the Richter scale.
The island sits in the middle of the Caribbean tectonic plate and the North American plate, and these two tend to collide.
According to USGS, the North American plate is being squeezed down under the Caribbean plate to the north of Puerto Rico, while to the south of the island, the top of the Caribbean plate is pushing itself down beneath the island. This combination causes frequent earthquakes throughout the island.
NASA reported on Friday that the quakes had moved the land in parts of southern Puerto Rico as much as 5.5 inches, based on satellite images before and after the temblors.
Scientists mapped the surface changes and their direction using data obtained from the European Space Union (ESA) Copernicus Sentinel 1A satellite with the onboard interferometric synthetic aperture radar (InSAR).
The data collected on January 9 was compared with the data from December 28, 2019 in order to be able to infer the changes.
The developed map shows changes on the eastern two thirds of the Puerto Rican island and indicates areas where the soil has been shifted. The area to the west of the city of Ponce (indicated by a green star on the map) shows the maximum displacement that extends up to 5.5 inches of ground change.
The scientists also find that the ground seems to have shifted downward and slightly to the west.
The orange circles on the map show the epicenter and aftershocks of the quake identified by the United States Geological Survey (USGS). Scientists are now using this satellite data to help federal and local authorities identify areas where damage is expected.
The scientists will also analyze data from the upcoming passage of the satellite on January 14th.