3.6-magnitude earthquake hits Eagle Ford town southeast of San Antonio

The U.S. Geological Survey has confirmed that a 3.6-magnitude earthquake hit an Eagle Ford Shale town about 44 miles southeast of San Antonio. The U.S. Geological Survey has confirmed that a 3.6-magnitude earthquake hit an Eagle Ford Shale town about 44 miles southeast of San Antonio. Photo: Houston Chronicle Photo: Houston Chronicle Image 1 of / 1 Caption Close 3.6-magnitude earthquake hits Eagle Ford town southeast of San Antonio 1 / 1 Back to Gallery

The U.S. Geological Survey confirmed that a 3.6-magnitude earthquake hit an Eagle Ford Shale town about 44 miles southeast of San Antonio.

The earthquake's epicenter registered about 2 miles north of the Karnes County town of Falls City just after 8 p.m. Saturday.

Karnes County Sheriff Dwayne Villanueva told the Houston Chronicle that there were no reports of damage but his agency received calls from residents in the nearby town of Hobson, who felt the shake.

Shaky Ground: USGS confirms four earthquakes in the Eagle Ford Shale

Out of the 16 earthquakes reported in South Texas by USGS this year, the Saturday evening quake was recorded as the strongest.

Environmentalists blame the tremors on saltwater disposal wells, which inject wastewater generated in the hydraulic fracturing process and other oil and natural gas activities deep underground.

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Saltwater disposal wells are regulated by the Railroad Commission of Texas, the state agency that regulates the oil and natural gas industry.

Railroad Commission officials adopted stricter regulations for saltwater disposal wells in November 2014. Over the last four years, the agency received 540 disposal well applications in areas of historic seismicity.

Of those proposed projects, 222 permits were issued with special conditions that include reducing maximum daily injection volumes and pressures as well as being required to record volumes and pressures on a daily basis as opposed to monthly.

Applications for 68 disposal sites were returned or withdrawn. Another 32 applications were sent to hearing while 25 permits were issued without special conditions and 193 applications are pending technical review.