Nuclear Test Rattles Las Vegas

A major nuclear weapons test with an explosive punch of up to 150,000 tons of TNT was detonated at the Nevada Test Site 100 miles northwest of Las Vegas this morning, causing high-rise buildings there to sway.

The test was the fifth announced shot in seven weeks following an unusual three-month lull in testing. The blast measured 5.5 on the Richter scale at the National Earthquake Information Center in Golden, Colo.