The Strength of the Geomagnetic Field at Earth's Surface (image) GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre Share Print E-Mail Caption The strength of the geomagnetic field at Earth's surface three times during the past: 48,500 and 47,250 thousand years ago and in 2015. The geomagnetic field of the past showed areas of weak intensity similar to today's South Atlantic Anomaly over South America and the southern Atlantic, for example 48,000 years ago. The anomaly of that time did, however, not lead to a geomagnetic field reversal, about one thousand years later the field recovered to a stable state of field strength. Credit M. Korte/GFZ Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.