Virginia isn’t the first place you think of when it comes to earthquakes. But, there are two long standing seismic zones here: one in Giles County in the southwestern part of the state and one in Central Virginia’s Louisa County. That’s where a magnitude 5.7 quake struck in the summer of 2011.
Virginia Tech geoscientist, Martin Chapman is studying the area where it hit in a town called Mineral.
“What is unusual is that it’s an extremely small rupture for the magnitude of the earthquake and the aftershocks are much more vigorous than what you’d expect for an earthquake this size in California.”
Chapman says, early indications, suggest east coast earthquakes behave differently than west coast quakes.
“And now we’ve discovered by the Mineral aftershock sequence, is that these eastern earthquakes can last for a very long time. So, 6 years down the road, we’re still seeing aftershocks."
Chapman says, overall, the number of earthquakes is not on the rise. An exception is places like Oklahoma, where fracking appears to be increasing their frequency.
He will present his findings this spring at a meeting of the Southeastern Section of the Geological Society of America.