Maybe I misunderstood. Didn’t the mine safety agency spokesman just say the incident last night was caused by seismic activity? I guess I just assumed this is from earth shifting, not due to the mining activity.
I’ll admit I know nothing about this.
The original mine collapse itself was the source of the seismic event that was recorded, not the result of a natural earthquake.
“Our seismologists at the University of Utah are careful not to rule out any possibility, but they tell me all of the available evidence indicates that the mine collapse itself the earthquake,” Lee Siegel, a University of Utah science news specialist, said Wednesday.”
Last night’s event was cause by natural ‘aftershocks’.
“Siegel said seismologists don’t know what is actually being felt on the ground at the mine during the rescue attempts but “are presuming it’s from settling.” Eleven aftershocks were recorded in 1 1/2 days after the collapse, Siegel said. The largest was magnitude 2.2.
The U.S. Geological Survey also says it appeared the initial tremor was the mine collapse rather than a quake. Mine collapses have a seismic signature distinct from earthquakes because they tend to occur at shallower depths and at different frequencies.”
I think that Murray is being adamant beyond reason about the original cause having been an ‘earthquake’, because something called ‘retreat mining’ may have been involved...
“Murray also lashed out at news media for suggesting his men were conducting “retreat mining,” in which miners pull down the last standing pillars of coal after mining out an area and let the roof fall in.”
Can you imagine how hard it must have come down to register as an almost 4 earthquake!
http://apnews.myway.com/article/20070808/D8QSSVT00.html