The Largest Event Of The Dfw Seismicity 3 Years After The Injection Termination - Is It An Evidence for Natural Origins Of Dfw Seismicity?

The study showed that the largest seismic event in the DFW area occurred more than 2 years after stopping of 9 months long salt water disposal injection. The largest event of September 30, 2012 with magnitude 3.4 (mblg) is similar to events occurring during the years 2008 and 2009. The events observed during the years of 2008 and 2009 became known as triggered by salt water disposal in the immediate vicinity of the DFW airport. However, seismological evidence shows that seismicity continues for more than 2 years after the waste water disposal was terminated, that the seismicity occurs along natural pre-existing fault, magnitudes of these events increase. These observations seem to be more consistent with natural creep along a slowly slipping fault.