The National Geomagnetism Program, also called the USGS Geomagnetism Program, is a United States Geological Survey (USGS) program that monitors the Earth's magnetic field through ground-based magnetic observatories. The program distributes geomagnetic data for government, academic, and private-sector users and conducts research on geomagnetic variation, space weather, and geoelectric hazards.
The program is part of the USGS Natural Hazards Mission Area and is based in the Geologic Hazards Science Center in Golden, Colorado. Its observatory network supports space-weather monitoring, magnetic-field mapping, scientific research, and hazard assessment for electric-power, pipeline, satellite, communications, navigation, and other infrastructure.
Overview
The program's mission is to monitor the Earth's magnetic field, maintain long-term records of magnetic-field variation, disseminate magnetic data, and conduct research for scientific understanding and hazard mitigation.1 It provides data to governmental agencies, academic researchers, and private industries, including users involved in global magnetic-field modeling, space-weather services, aeromagnetic surveys, directional drilling, pipelines, and electric-power-grid operations.1
Ground-based observatories are important in space-weather monitoring because the practical effects of geomagnetic storms are often measured at or near Earth's surface. Large magnetic storms can interfere with radio communications and GPS accuracy, affect satellites, increase pipeline corrosion, and induce voltage surges in electric-power grids.2
Observatory network
The USGS operates 14 magnetic observatories in the United States and its territories. Magnetometer data from the observatories are transmitted to program headquarters in Golden. The network's geographic distribution is intended to support space-weather diagnosis, main-field modeling and mapping, and coordination with observatories operated by other national geomagnetism programs.3
The observatories listed by the USGS are Boulder, Barrow, Stennis, College, Deadhorse, Fredericksburg, Fresno, Guam, Honolulu, Newport, Shumagin, Sitka, San Juan, and Tucson.3 The International Federation of Digital Seismograph Networks identifies the program's network code as NT and describes it as monitoring the magnetic field at 14 ground-based observatories in the United States.4
The USGS works with other national geomagnetism programs through INTERMAGNET, a consortium of observatory programs, and through the International Association of Geomagnetism and Aeronomy.1
Research and data products
The program's research plan for 2020–2024 focused on estimating and mapping geomagnetic disturbance, modeling solid-Earth conductivity and surface impedance, and mapping magnetic-storm-induced geoelectric fields. The plan described the work as relevant to understanding ground-level space-weather disturbance and evaluating the vulnerability of electric-power-grid systems.5
USGS data products include real-time observatory data feeds and derived products used in geomagnetic monitoring and geoelectric hazard modeling.6 The program also provides calibration, consultation, and compass-rose survey services related to magnetic instruments and magnetic-facility operations.1
History
The program traces its origins to the federal coastal survey work authorized by the Congress in the 1840s, which included responsibility for geomagnetic surveys.7 During the 19th century, U.S. agencies established short-lived magnetic stations and produced magnetic-declination maps for the United States and its territories. The Coast and Geodetic Survey created a Division of Terrestrial Magnetism in 1889 after the purchase of Alaska increased the importance of coastal surveys.7
Permanent observatories began with the Cheltenham Magnetic Observatory in Maryland in 1900, followed by Sitka in Alaska in 1901 and Honolulu in Hawaii in 1902. Cheltenham was replaced by the Fredericksburg observatory in Virginia in 1956.7 Several observatories were established in the 1950s as part of the International Geophysical Year.8
The magnetic and seismological programs of the Coast and Geodetic Survey were united in 1925 under the Division of Geomagnetism and Seismology. The Coast and Geodetic Survey became part of the National Oceanic and Atmospheric Administration in 1970, and in 1973 the USGS assumed responsibility for the national geomagnetism and seismology programs.7
Other geomagnetic survey work influenced the broader U.S. observing record. The Carnegie, a non-magnetic survey ship operated by the Carnegie Institution of Washington, began its first cruise in 1909 and ultimately made seven major cruises between 1909 and 1929 that returned magnetic and oceanographic observations.9 The Boulder magnetic observatory has been operated by the USGS Geomagnetism Program since 1963 and supports scientific uses, developmental work, and collaborative projects.10 The Magsat satellite, launched in 1979, measured Earth's magnetic field from orbit; NASA described its data as supporting USGS preparation of 1980 world magnetic-field charts and detection of large-scale crustal magnetic anomalies.11
References
References
- "What We Do – Geomagnetism Program". U.S. Geological Survey. Retrieved May 23, 2026.
- Love, Jeffrey J.; Finn, Carol A. (July 2, 2011). "The USGS Geomagnetism Program and its role in space weather monitoring". Space Weather. 9 (7). doi:10.1029/2011SW000684. Retrieved May 23, 2026.
- "Observatories". U.S. Geological Survey. July 20, 2018. Retrieved May 23, 2026.
- "NT: USGS Geomagnetism Program". International Federation of Digital Seismograph Networks. Retrieved May 23, 2026.
- Love, Jeffrey J.; Kelbert, Anna; Murphy, Benjamin S.; Rigler, Eric J.; Lewis, Kristen A. (2020). Geomagnetism Program research plan, 2020–2024 (Report). Circular. U.S. Geological Survey. doi:10.3133/cir1469. Retrieved May 23, 2026.
- "Geomagnetism – Data & Tools". U.S. Geological Survey. April 14, 2023. Retrieved May 23, 2026.
- Love, Jeffrey J.; Townshend, J. B. (2007). "Observatories, program in USA". Encyclopedia of Geomagnetism and Paleomagnetism. Springer. doi:10.1007/978-1-4020-4423-6_231. Retrieved May 23, 2026.
- National Geomagnetism Program: Developing a Staffing Plan – Geologic Hazards Team – 2003 (PDF) (Report). Open-File Report. U.S. Geological Survey. 2006. pp. 8–9. Retrieved May 23, 2026.
- Harrison, R. Giles; Aplin, Karen L. (2013). "The Carnegie Curve". Surveys in Geophysics. 34 (2): 209–232. doi:10.1007/s10712-012-9210-2. Retrieved May 23, 2026.
- Love, Jeffrey J.; Finn, Carol A.; Pedrie, Kolby L.; Blum, Cletus C. (2015). The Boulder magnetic observatory (PDF) (Report). Open-File Report. U.S. Geological Survey. doi:10.3133/ofr20151125. Retrieved May 23, 2026.
- Mobley, F. F.; Eckard, L. D.; Fountain, G. H.; Ousley, G. W. (September 1, 1980). Magsat: A new satellite to survey the Earth's magnetic field (Report). NASA Technical Reports Server. Retrieved May 23, 2026.