PITTSBURGH — A meteor that caused an earthshaking boom over suburban Pittsburgh on New Year's Day exploded in the atmosphere with an energy blast equivalent to an estimated 30 tons of TNT, officials said.

NASA's Meteor Watch social media site said late Sunday a “reasonable assumption” of the speed of the meteor at about 45,000 mph would allow a “ballpark” estimate of its size as about a yard in diameter with a mass close to half a ton.

If not for the cloudy weather, NASA said, it would have been easily visible in the daytime sky — maybe about 100 times the brightness of the full moon.

A nearby infrasound station registered the blast wave from the meteor as it broke apart, enabling the estimates.

Residents in South Hills and other areas reported hearing a loud noise and feeling their homes shaking and rattling. Allegheny County officials said they had confirmed that there was no seismic activity and no thunder and lightning.