USVI to Host Geological Survey Flight Campaign This Month

The U.S. Geological Survey announced on November 12 that it will conduct an airborne mapping campaign across the U.S. Virgin Islands and nearby waters during the current month. The initiative aims to gather data on earthquake, tsunami and landslide hazards affecting the region.

Fixed-wing aircraft will traverse predetermined routes at a nominal altitude of 330 feet, or 100 meters, operating only in daylight. The agency has not disclosed specific start or end dates for the work.

The survey will employ a DHC-6-300 Twin Otter aircraft bearing the registration C-GSGP. Residents may observe a tail-mounted sensor apparatus, commonly called a "stinger," which collects magnetic field data. According to USGS, these instruments are non-emitting, pose no hazard to people or wildlife, and will not capture photographs or video footage.

Three airports will serve as operational bases: Henry E. Rohlsen on St. Croix, Cyril E. King on St. Thomas, and José Aponte de la Torre in Puerto Rico. Sander Geophysics and Dewberry have been contracted to execute the data collection.

The campaign builds on recent magnetic surveys conducted over Puerto Rico. The region's geologically complex structure generates substantial earthquake and tsunami risk. Mapping subsurface rock formations in shallow offshore areas will enable researchers to locate and characterize active underwater faults, the USGS said.

Flight spacing will vary based on local geology and seabed depth: approximately 820 feet apart over shallower zones and 6,500 feet apart over deeper zones. Pilots will hold special certification for low-altitude operations and will coordinate with the Federal Aviation Administration to maintain compliance with U.S. aviation regulations.

Brita Jessen, director of the USGS Woods Hole Coastal and Marine Science Center, noted that airborne magnetic mapping can help identify offshore tectonic faults and clarify the distribution of potential resources, including marine minerals.

The project merges two USGS initiatives: the Earth Mapping Resources Initiative, which upgrades geological and resource surveys, and the Coastal and Marine Hazards and Resources Program. All data gathered will be released publicly through the USGS ScienceBase platform at no cost.