Texas was not an earthquake state until it became one. The rise in small and moderate earthquakes in the Permian Basin and North Texas since the mid-2010s tracks the rise in deep saltwater disposal, and the state's response has reshaped where disposal is permitted and how it is reported.
TexNet
In 2015 the Texas legislature funded TexNet, a statewide seismic monitoring network operated by the Bureau of Economic Geology at the University of Texas. It began reporting in 2017 and today locates earthquakes across the state down to magnitudes well below what people feel. TexNet contributes its catalog to the USGS, which is the stable public interface for the data. Petrora loads located events daily from that catalog.
Each event carries a time, location, depth, and magnitude. Depth matters: induced events are typically shallow, in or near the disposal interval, and the TexNet catalog is one of the few that resolves that.
Seismic response areas
When earthquake clusters appear near disposal activity, the RRC defines a seismic response area (SRA) and issues operators in it a response plan. Plans have included volume cuts, pressure limits, suspension of deep disposal permits, and daily reporting of injection volumes through TexNet. The first and best known are the Gardendale SRA near Midland and Odessa and the Northern Culberson-Reeves SRA in the Delaware Basin, both defined in 2021, followed by the Stanton SRA. Within these areas, deep disposal has been curtailed and new permits face conditions that do not apply elsewhere.
This is the mechanism behind the TexNet injection reporting described in saltwater disposal: the reporting requirement exists because of the SRAs.
How Petrora relates earthquakes to wells
On the page of any injection well with a known location, Petrora counts earthquakes of magnitude 2 and larger within 10 kilometers over the last two years, and shows the largest. This is a proximity count, not an attribution. A count of zero does not mean the well is safe to expand, and a count of thirty does not mean the well caused them; it means the well sits in an active area, which is what a permit reviewer or a buyer wants to know first.
The thresholds were chosen for signal: magnitude 2 is roughly the floor at which the catalog is complete across the Permian, and 10 kilometers is on the scale at which pressure effects from deep disposal are observed.