With funding from the Bipartisan Infrastructure Law, the U.S. Geological Survey is investing $1,000,000 in geological mapping in Puerto Rico. The project, part of the Earth Minerals Resources Initiative, will begin with the first high-resolution airborne magnetic and radiometric surveys of the Island.
These surveys will be conducted by airplanes, which will be equipped with magnetic sensors. These sensors will be able to identify features like earthquake faults, rock formations, aquifers, and minerals such as potassium, uranium, and thorium. The resulting maps will show both potential dangers and potential deposits of valuable minerals.
Earlier magnetic surveys were flown over small parts of the Island in 1957 and 1962, before GPS and digital recording. The sensors used at that time were quite different from the modern sensors. The type of survey currently planned has never been performed before for Puerto Rico.
A recent geologic map of Alaska shows the results of this type of survey.
One of the benefits of the surveys will be better identification of earthquake faults. The map at the top of this page shows the locations of earthquakes in Puerto Rico. The depth of the quakes is shown by the different colors.
“Understanding the geology of Puerto Rico through the data these surveys provide will help give us a clearer understanding of the faults that generate these earthquakes,” said USGS Director David Applegate. “Having that knowledge will allow the Puerto Rican government and scientists to plan how to mitigate geologic-hazard risks to communities on the island.”
The information gathered will also help predict and allow planning for sea level rise, erosion, and other challenges.
The surveys will also help to identify mineral deposits which could have economic potential. Puerto Rico has sand and gravel and other minerals used in construction, as well as some deposits of precious metals. However, there may also be rare earth elements or other minerals that could be mined. New technologies require different kinds of minerals, and the chances of undiscovered sources are good.
The United States currently relies heavily on imported minerals. Finding native deposits of these essential resources would be very beneficial for the nation as a whole. Naturally, any undiscovered deposits found in Puerto Rico would be of economic importance to the Island as well.