South Texas shaken by 27 earthquakes in February alone

The USGS has previously noted that many quakes that occur throughout the southern Plains have been tied to human activities such as fracking. Many of the recent quakes occurred in the Eagle Ford Shale area, which is an important region for gas and oil production.

FALLS CITY, Texas – A region of South Texas between San Antonio and Corpus Christi is the latest area to become a hotbed for seismic activity, with the newest quake estimated to be a magnitude-3.9.

According to the United States Geological Survey, the moderate quake occurred Friday evening near Falls City, Texas, and was centered about five miles underground.

According to early reports, the shaking was not felt by many Texans and was mostly isolated southeast of Interstate 35 outside of San Antonio.


The quake was the greatest out of at least 27 that have been detected by seismographs during February in South Texas. Many of the quakes have had magnitudes of between 1.5-2.5 and have not produced any damage.

The USGS has previously noted that many quakes throughout the southern Plains have been tied to human activities.

The agency said fracking - the process of injecting water, sand or chemicals into the ground in order to break up the bedrock to reach oil and gas reserves – can trigger quakes and impact groundwater.

Quakes caused by oil fracking are known as "induced earthquakes" as opposed to "natural earthquakes," which are triggered by plate tectonics.

Many of the more than two dozen earthquakes have occurred in a region identified as the Eagle Ford Shale area.

The hydrocarbon-producing geological formation stretches from the Mexican border to near Waco and is important for gas and oil production.


According to the U.S. Energy Information Administration, the Eagle Ford region produces over 1.1 million barrels of oil and 7.4 million cubic feet of gas per day.

The USGS hasn’t directly tied the latest earthquake swarm to human activities, but the agency will likely examine data in consultation with experts in Texas to determine whether the shaking was induced by fracking or is the result of plate tectonics.