The USGS Geomagnetism Program operates a network of magnetic observatories that collect vector and scalar magnetometer data for use in Earth main-field modeling, geophysics research, space physics research, and space weather hazard assessment and mitigation. Until mid-2011, only 1-minute time resolution magnetic field measurements were archived with the INTERMAGNET consortium following international magnetic observatory standards. 1-second time resolution magnetic field measurements, which had already been collected by all the USGS observatories for up to almost a decade prior, started being archived with INTERMAGNET on June 13, 2011, or July 27, 2012 in the case of the more recently constructed Deadhorse (DED) magnetic observatory. This data release contains 1-second time resolution magnetic field measurements collected up through the end of 2012, after which time 1-second data from USGS magnetic observatories may be obtained from INTERMAGNET. There is some overlap between data in this release and those data archived with INTERMAGNET. Any discrepancies that may exist between these two data sources should resolve in favor of INTERMAGNET. SHU-specific notes: - there are significant gaps in the 2003 data, most notably in late November through December - there are significant gaps in the 2004 data, most notably in January and February - some filenames originally possessing a ".sec" extension were renamed to ".raw"

The USGS Geomagnetism Program operates a network of magnetic observatories that collect vector and scalar magnetometer data for use in Earth main-field modeling, geophysics research, space physics research, and space weather hazard assessment and mitigation. Until mid-2011, only 1-minute time resolution magnetic field measurements were archived with the INTERMAGNET consortium following international magnetic observatory standards. 1-second time resolution magnetic field measurements, which had already been collected by all the USGS observatories for up to almost a decade prior, started being archived with INTERMAGNET on June 13, 2011, or July 27, 2012 in the case of the more recently constructed Deadhorse (DED) magnetic observatory. This data release contains 1-second time resolution magnetic field measurements collected up through the end of 2012, after which time 1-second data from USGS magnetic observatories may be obtained from INTERMAGNET. There is some overlap between data in this release and those data archived with INTERMAGNET. Any discrepancies that may exist between these two data sources should resolve in favor of INTERMAGNET. SHU-specific notes: - there are significant gaps in the 2003 data, most notably in late November through December - there are significant gaps in the 2004 data, most notably in January and February - some filenames originally possessing a ".sec" extension were renamed to ".raw"

This map of the magnetic total field was derived from data acquired during an aeromagnetic survey carried out by Fugro Airborne Surveys during the period April 17, 2006 to August 26, 2007. The data were recorded using a split-beam cesium vapour magnetometer (sensitivity = 0.005 nT) mounted in the tail boom of a Cessna Caravan aircraft. The nominal traverse and control line spacings were, respectively, 800 m and 2600 m, and the aircraft flew at a nominal terrain clearance of 250 m. Traverse lines were oriented N30 degrees E with orthogonal control lines. The flight path was recovered following post-flight differential corrections to the raw Global Positioning System data and inspection of ground images recorded by a vertically-mounted video camera. The survey was flown on a pre-determined flight surface to minimize differences in magnetic values at the intersections of control and traverse lines. These differences were computer-analysed to obtain a mutually levelled set of flight-line magnetic data. The levelled values were then interpolated to a 200 m grid. The International Geomagnetic Reference Field was not removed from the magnetic total field.