A pair of small earthquakes over the weekend rattled a few small Texas towns, including Tilden, located about an hour south of San Antonio.
The quakes join a growing list of small earthquakes in the area over the last few years.
With each one, questions arise over their cause, and the culprit -- according to many -- is hydro-fracking operations in the Eagle Ford shale zone.
The earthquake over the weekend was 3.4 on the Richter scale.
The first comprehensive study on the seismic effects of hydraulic fracturing argued the practice rarely causes earthquakes, although admits the possibility exists.
The reports said hydro-fracking has never caused an earthquake in Texas.
The common practice of re-injecting waste water created during the hydro-fracking process has caused an earthquake, according to the report.
Different groups on both sides of the issue have used the report to push their own agendas.
Pro-drilling advocates have cited the report as proof of hydro-fracking safety, while those not in favor of the practice have said the report acknowledges the earthquake threat.