Speaking of deep tunnels, several geologists from
government and academia are discerning a pattern of Midwestern earthquakes
associated with deep well injection of industrial waste water. The background
rate of midcontinent U.S. earthquakes was about 20 per year. In 2008 there were
29, then 87 in 2010 and 134 in 2011. U. S. Geological Survey seismologist Bill
Ellsworth noticed clusters of these quakes near industrial wastewater wells in
Oklahoma and Colorado. The theory is that the injected waste water lubricates
existing earth crust faults, accelerating earthquake occurrence.
“Small perturbations can tip the scales,” Ellsworth
says, “allowing an earthquake that might not otherwise happen for a very long
time.” University of Memphis
seismologist Steve Horton has tracked a swarm of similar quakes in 2010 and
2011 along an Arkansas fault line. “The earthquakes that happened then in a
swarm followed the startup of two waste disposal wells that were within 5
kilometers of this fault.” Horton says. “The earthquakes started after the
injection at the two wells started, and they stopped after the injection
stopped.”
Columbia University seismologist John Armbruster
has been monitoring a series of significant quakes near wastewater injection
sites in Youngstown and Marietta, Ohio. The
biggest Youngstown quake was the day after injection of wastewater into the
well there stopped. “The number of earthquakes there has dramatically reduced,
which I would think you would take as evidence that the well was triggering the
earthquake,” Armbruster remarks.
