LA SALLE COUNTY — The United States Geological Survey reported a 3.6-magnitude earthquake in La Salle County, Texas, on July 12, 2026. The temblor occurred at approximately 3:52 p.m., with its epicenter located about 7.5 miles southeast of Dilley and at a depth of 4.2 miles.

La Salle County is a rural county in South Texas with a population of 6,886, according to the most recent census data. The region lies within the Eagle Ford Shale formation, an area that has seen significant energy development over the past two decades.

Scientific studies have examined the geological characteristics of La Salle County in relation to oil and gas extraction. Research published in 2015 in the journal Environmental Management analyzed how above-ground activities associated with the Eagle Ford Shale play have affected local landscapes and hydrologic systems. Another 2015 study presented at the Unconventional Resources Technology Conference investigated how natural fractures in the Eagle Ford formation influence well productivity in La Salle County.

Why It Matters

Earthquakes in regions like South Texas, where seismic activity has historically been low, can raise questions about their relationship to subsurface industrial operations. The USGS monitors all seismic events regardless of magnitude or location to maintain a comprehensive record of ground motion across the United States. This 3.6-magnitude event adds to the catalog of minor quakes reported in the area in recent years, contributing to ongoing analysis of regional seismic patterns.