Seismographs pick up explosion as big as 4.5 earthquake in area of Wyoming coal mine

May 4, 2012 – WYOMING – As Mexico was being jolted by a series of moderate-to-strong earthquakes the other day, Wyoming got into the earth-shaking act, too. The USGS recorded a magnitude 4.5 near Sleepy Hollow at 10:11 a.m. MT (12:11 p.m. ET). Turns out it was caused by mine blasting. The “Fake Quake of 2012” was ‘really an amplified echo of an unusually large mine blast,” about 17 miles south of Gillette, the Casper Star-Tribunewrites. A USGS geophysicist based in Golden, Colo., said the explosion actually registered as magnitude 3.0. Locals said they didn’t feel a thing. “The only question now is: who set off an explosion that big at 10:12 a.m. somewhere in rural Campbell County?” the paper wondered. An explosion at a coal mine northeast Wyoming was big enough to register on seismographs on the scale of a small earthquake. Some people in Gillette reported feeling the ground shake from 16 miles away. The U.S. Geological Survey recorded the blast at 11:11 a.m. Tuesday. The blast registered as large as a magnitude 4.5 magnitude earthquake but had the signature of a human-caused explosion. The Gillette News-Record reports using explosives is a routine part of remove dirt and soil at the coal mines where the blast occurred southeast of Gillette. The explosion happened in the area of Cloud Peak Energy’s Cordero Rojo mine. Mine explosions that register with such force are rare. Sheriff’s officials said they had not heard of any emergency at the mines. –The Republic

contribution Josh B.