Me too, Everybody figured it was South Africa’s Nuke test......................
I am surprised given the state of things in SA that info about this has not been leaked. Also, who is in control of these weapons today? The ANC?
The writer did not mention the South African-Isreali political connections at the time: BOTH were being attacked internally and through the UN by the Communist parties. (Both still are, though the communists won in Africa.) It is possible it was an Israeli nuke being tested off of Africa on a barge or ship towed from an SA port.
Or just a meteor impact-Tunguska style atmospheric flash. There is only the surveillance satellite “description” of a double flash. Is that description correct? At the time, meteor impacts were not thought to be very common - Now, we have seen worldwide video’s of impacts in the atmosphere every year. The nuke explosion theory is bolstered by this (now much older!) radiation story.