Airborne magnetic flight line data, Charleston, South Carolina and surrounds, 2019

Airborne magnetic gradiometry data are provided here as part of the data release, "Airborne magnetic and radiometric survey, Charleston, South Carolina and surrounds, 2019." This data release includes the processed aeromagnetic horizontal gradiometry flight line data provided in an ascii .csv file and a geoTIFF image showing the magnetic intensity in nanoTeslas (nT). The contractor report and deliverables package are available on the parent page, https://doi.org/10.5066/P9EWQ08L. These data were collected as part of a high-resolution airborne magnetic and radiometric survey over Charleston, South Carolina and the surrounding region with a goal of better understanding earthquake hazards in the Charleston seismic zone by imaging structural features in the crystalline basement, and to image heavy mineral sands containing titanium, zirconium, and rare earth elements using radiometric data (gamma spectrometry), which is sensitive to thorium in monazite. This survey represents a collaborative effort by the U.S. Geological Survey (USGS) Earthquake Hazards Program, Mineral Resources Program, National Cooperative Mapping Program, and Earth Mapping Resource Initiative (Earth MRI) effort. Data for this survey were collected by Terraquest, Ltd. under contract with the USGS using a fixed wing aircraft with magnetometers mounted in the tail stinger and each wing tip pod and a fully calibrated gamma ray spectrometer from May to July of 2019. The survey covers a 134-kilometer x 90-kilometer rectangular area parallel to the Atlantic Ocean shoreline along the long axis. Data were collected along northwest-southeast flight lines spaced 400 meters (m) apart with northeast-southwest tie lines flown every 4000 m. A mean terrain clearance of 127 m was maintained. Most of the survey data were collected at lower flying heights, except near and over the City of Charleston higher clearance was maintained due to safety considerations. A total of 32,447-line kilometers (km) of data were collected.