Airborne magnetic and radiometric survey over Puerto Rico and the Surrounding Islands and Shelf, 2023-2024

This data release provides digital flight-line and gridded data for a high-resolution airborne magnetic and radiometric survey over Puerto Rico, the islands of Vieques and Culebra, and the surrounding shelf. The survey was acquired through funding from the USGS Earth Mapping Resource Initiative (Earth MRI), the USGS Coastal and Marine Resources and Hazards Program, and the USGS Earthquake Hazards Program with goals of to improve our understanding of the fundamental geologic framework of the region with applications to evaluating natural resources and geologic hazards.

Data for this survey were acquired and processed by Terraquest under contract to Dewberry and the USGS. The survey was flown in two periods, from March 2023 to May 2023 and December 2024 to March 2025 using a fixed-wing airplane. A total of 70,031 linear kilometers of data were collected. Pre-planned traverse flight lines were flown in an N-S direction with 250-m line spacing and E-W tie-lines with 2500-m line spacing except in two areas over deeper water, where the traverse flight lines were flown with a 500-m line spacing. The nominal flight height was 120 meters (m) above ground, with areas having higher population densities flown at a nominal height of 330 m above ground for safety reasons. The area over El Yunque National Forest was flown with a nominal height of 330 m so not to disturb wildlife below. Following acquisition, Terraquest also performed post-processing of the data and delivered the final databases, grids, and images. Details regarding the flights and data processing are described in the contractor report provided in this release.