PAHUTE MESA, Nev. -- A nuclear bomb up to 11 times more powerful than the one dropped on Hiroshima swayed buildings 100 miles away just one day after the United States and Soviet Union agreed to reopen talks on nuclear testing.
The purpose of Thursday's underground test, code-named 'Cybar,' was not disclosed by the Department of Energy, but some recent experiments have been designed to gather data on the Strategic Defense Initiative popularly known as 'Star Wars.'
The test, delayed six hours because of adverse wind conditions, generated earth tremors felt in Las Vegas 102 miles from ground zero. Occupants of high-rise gambling resorts on the Las Vegas 'Strip' felt a slight swaying motion.
The test was conducted the day after White House officials said the Kremlin agreed to expert-level talks on 'issues related to nuclear testing'.
The agreement to meet on nuclear testing was announced in London Wednesday by Soviet Foreign Minister Eduard Shevardnadze several hours before any official word from the White House. The United States has continued nuclear weapons tests for the past year despite a self-imposed Soviet moratorium in August 1985.
The tremor measured 5.6 on the Richter scale, the equivalent of an earthquake capable of causing wide damage, scientists at the National Earthquake Center in Golden, Colo., said. A quake measuring 5.9 last week near Palm Springs, Calif., injured 40 people and caused some $6 million damage.
'The hanging plants in my dining room moved back and forth,' said Mary Miller in Las Vegas. 'It lasted several minutes. They swayed in an east-west direction. The wind chimes even started ringing.'
It takes about 45 seconds for the earth motion to travel the distance between Pahute Mesa and downtown Las Vegas
Instruments detected directional motion at Las Vegas's high-rise Regency Towers and the Imperial Palace Hotel-Casino, as well as at Scotty's Castle in Death Valley and at the Crowell Mine on the southwest border of the giant Nevada Test Site.
The weapon, which was buried in a 2,100-foot shaft, had a yield of 20 to 150 kilotons, or a maximum equivalent of 150,000 tons of TNT. The bomb dropped on Hiroshima was a 13-kiloton weapon.
'No radiation leaked into the atmosphere. The test was very successful,' Energy Department spokesman Jim Boyer, who was 12 miles from the blast and said ground motion was 'very strong.'
The earth directly above the blast bounced several feet as the explosion carved out an underground cavern large enough to accommodate two football fields. A cloud of sand rose into a clear desert sky.
The device was detonated 45 years and one day after the dawn of the Atomic Age, when top-secret Manhattan Project scientists exploded a 19 kiloton atomic bomb code-named 'Trinity' over the New Mexico desert on July 16, 1945.