Ultralow-Frequency Magnetic Fields Preceding Large Earthquakes
Article first published online: 3 JUN 2011
©2008. American Geophysical Union. All Rights Reserved.
Eos, Transactions American Geophysical Union
Volume 89, Issue 23, page 211, 3 June 2008
How to Cite
2008), Ultralow-Frequency Magnetic Fields Preceding Large Earthquakes, Eos Trans. AGU, 89(23), 211–211, doi:10.1029/2008EO230007.(
- Issue published online: 3 JUN 2011
- Article first published online: 3 JUN 2011
The Great Alaska Earthquake (M 9.2) of 27 March 1964 was the largest earthquake ever to strike the United States in modern times and one of the largest ever recorded anywhere. Later that year, Moore , in a surprisingly rarely cited paper, reported the occurrence of strong ultralow-frequency (ULF; ≤10 hertz) magnetic field disturbances at Kodiak, Alaska, in the 1–2 hours before the earthquake. That report has since been followed by others [Fraser-Smith et al., 1990; Kopytenko et al., 1993; Hayakawa et al., 1996; see also Molchanov et al., 1992] similarly describing the occurrence of large-amplitude ULF magnetic field fluctuations before other large earthquakes (“large” describes earthquakes with magnitudes M ∼7 or greater). These reports involving four separate, large earthquakes were made by four different groups and the results were published in well-known, refereed scientific journals, so there is no doubt that there is evidence for the existence of comparatively large ULF magnetic field fluctuations preceding large earthquakes.