Rare Strong Earthquake Hits Colorado
From The New York Times
By KIRK JOHNSON
DENVER — The largest natural earthquake in Colorado in more than a century struck Monday night in the state's southeast corner, but there were no reports of damage or injuries.
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The quake, with a preliminary magnitude of 5.3, was centered about nine miles from the city of Trinidad and hit at 11:46 p.m. local time. It was felt as far away as Greeley, about 350 miles north, and into Kansas and New Mexico, said Julie Dutton, a geophysicist at the National Earthquake Information Center in Golden, Colo.
Colorado, with its mix of mountains and plains, sits astride a seismically stable part of the nation where earthquakes are mostly mild and far between. But the area around Trinidad is regularly hit by tiny quakes as a result of a local fault zone, Ms. Dutton said.
She said that while Colorado had experienced several earthquakes close to Monday's size in recent decades — a magnitude 5.3 near Denver in 1967 and a magnitude 5.7 in the state's northwest corner in 1973 — both of those quakes were ultimately determined to have been caused by human activity, from explosives or drilling.
The last known natural event of comparable size was an earthquake in 1882 in what is now Rocky Mountain National Park. That quake, based on historical reports, was about a magnitude 6.5, Ms. Dutton said.