Did Fracking Cause Sparks Quake?

 A record  5.6 magnitude earthquake in Oklahoma.  And fracking has been shown to cause at least small ones.  In fact, a number earlier Okla. quakes may have been caused by the process.  Here's a graph showing the recent up-tick in seismic for Texas and Oklahoma.

Be interesting to find out if they can be correlated to any uptick in the use of the extraction technique in these two states.

More here.