Letter | Published:

Was the 1970 geomagnetic jerk of internal or external origin?

Nature volume 296, pages 726728 (22 April 1982) | Download Citation

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Abstract

Annual mean data from worldwide magnetic observatories show that there was a jerk1 (step-change in the second time derivative) in the geomagnetic field, which took place over an interval of <2 yr around 1970. If such a short-lived phenomenon originated in the Earth's core, and were still detectable after passing through the mantle to the surface, this would imply a much lower conductivity for the lower mantle than had been believed previously. Here we show by an objective test that most of the jerk has an internal origin.

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Affiliations

  1. Institute of Geological Sciences, West Mains Road, Edinburgh EH9 3LA, UK

    • S. R. C. Malin
    •  & B. M. Hodder

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DOI

https://doi.org/10.1038/296726a0

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