External Geomagnetic Field Variations And Magnetic Surveys

The magnetic storm which started al 01h25 on the 131h of March 1989, was probably the largest event of its kind to be recorded in South Africa since magnetic held recordings began in 1932. Soon after its commencement, the Magnetic Observatory started receiving enquiries about the anticipated development of the storm from a few exploration groups who were doing aeromagnetic surveys al the time.