I also recall a map that shows very little earthquake activity in the U.S. outside the usual zones (California, for example), except that in Oklahoma the frequency of earthquakes, and their magnitude, has increased rapidly since the introduction of heavy fracking in the state.
The map you provided does not show increases in activity. It just shows total earthquake activity from 2008-2012. Is the indicated activity for say Ohio or Texas normal or is it fracking enhanced? Is the activity shown for Wyoming normal? Your map gives no fracking basis for reaching a conclusion.
I figured EvC is a better place to explore the issue in more depth than to hopelessly hunt for news clippings.
A cursory search will turn up reports of fracking related earthquakes in Ohio, Texas, and Oklahoma. I suppose that since this is a discussion group, you might just as well ask as to do the slightest bit of homework on your own.
At any rate, here is a relevant gubmit comment on the issue
http://earthquake.usgs.gov/research/induced/
quote:
A team of USGS scientists led by Bill Ellsworth analyzed changes in the rate of earthquake occurrence using large USGS databases of earthquakes recorded since 1970. The increase in seismicity has been found to coincide with the injection of wastewater in deep disposal wells in several locations, including Colorado, Texas, Arkansas, Oklahoma and Ohio. Much of this wastewater is a byproduct of oil and gas production and is routinely disposed of by injection into wells specifically designed and approved for this purpose.
Hydraulic fracturing, commonly known as fracking, does not appear to be linked to the increased rate of magnitude 3 and larger earthquakes.
Note that the government is saying what others have said: that the primary culprit is oil and gas production. Fracking has some effect but tends to be associated with smaller seismic activity.
Je Suis Charlie
Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass