Here's a clip of WCAU's NewsBeat program. It's shortly before 5 pm on Saturday, November 6, 1971 and the voice is that of Al Julius.

The test he is talking about was called Project Cannikin, a nuclear test conducted on Amchitka Island, Alaska, at 5 pm, Eastern Time on November 6, 1971. Cannikin, a slightly less-than-five-megaton device, was the largest underground nuclear test conducted in the United States. It was conducted to proof test a warhead for the Spartan missile, a Safeguard Ballistic Missile Defense Program.

This event was just one of three parts of underground nuclear testing performed at various places on this island in the Aleutian Chain. It's just 43 miles long and was a $200 million project. It was detonated in a 50-foot diameter area, on the low end of a 5,875-foot chamber. The island of Amchitka is 1400 miles west of Anchorage and was a military outpost during the Second World War and its air field and its base camp from that facility were reused for the nuclear testing experiment.

Its shock registered 7.0 on the Richter scale, a seismic unit of measurement. Formed was a crater more than one mile wide and 40 feet deep. Project Cannikin was a giant undertaking involving hundreds of lab employees with nearly five years of planning.