The surge in Eagle Ford production over the past few years has likely led to small earthquakes in the region.

Enough oil and water is now being produced that it is likely rocks are settling and faults are slipping, which causes small earthquakes.

That's the conclusion from a two-year study completed by the UT Institute for Geophysics.

The study was published in the Earth and Planetary Science Letters.

Findings from the study include:

• No link found between hydraulic fracturing and earthquakes
• Authors compare South Texas to California during the oil boom of the 20th century
• Earthquakes are likely linked to areas of oil & gas production and are often undetectable at the surface

In other studies, seismic activity was linked to waste water injection wells. Both a UT study in the Barnett and a USGS study in Ohio have linked earthquakes to injection wells. The results of this study seem to indicate we're going to find differences across regions.

[ic-l]*Note - The study was done while the National Science Foundation had measurement tools in place that have never been available in South Texas. 58 of the tremors measured were not recorded by tools the USGS has in place. I trust the researchers at UT, but it is tough to call a two year peek into eons of data a significant sample size. This probably won't be the last study on the topic, so we'll have to watch for additional data points as they become available.

Read more from Tom Fowler at wsj.com