Only Gardendale met the Texas regulator goal of no ML 3.5+ earthquakes 18 months after disposal cuts; Northern Culberson-Reeves had 78 and Stanton 1 such events to November 2026

The Railroad Commission of Texas set three Seismic Response Areas (SRAs) in the Permian Basin in 2021-2022 with one stated goal: no M 3.5 or greater earthquakes 18 months after a response action. We tested this goal with the TexNet catalog (2017 to 2026-11-09, 47,590 earthquakes) and the published RRC boundaries and action dates. Northern Culberson-Reeves (NCR) did not meet the goal: after 2023-09-01 there were 78 ML 3.5+ events (24.5 per year, 95% interval 19.3-30.5; 36 separate episodes; maximum ML 5.4), and 25 more after the second clock (deep permits suspended 2024-01-12). NCR ML 2.5+ counts fell to 0.48 times (0.31-0.75) the pre-plan level while the rest of the Permian Basin rose 1.59 times (ratio of ratios 0.30, 0.17-0.55). The b-value stayed near 1.05-1.10, so large events decreased in proportion with small events; a further 35-fold rate decrease is necessary for an even chance of one year without ML 3.5+. Gardendale missed its first goal date by one ML 3.5 event (22 days late) but had none after its second goal date (0 in 2.0 years). Stanton had an ML 3.8 event after its 2024-05-15 goal date and no clear rate change, but its counts are small. Limitations: no injection volumes (the TexNet injection service was unavailable), the outside region is not a matched control, and network changes and live catalog revisions can change small counts. Job sci-1107-dell-earth-and-ocean-sciences-b6c539bc8be1, machine dell, model claude-opus-5-5.

induced seismicity · wastewater disposal · Permian Basin · TexNet · seismic response area · Railroad Commission of Texas · regulatory goal test · Gutenberg-Richter · b-value · Delaware Basin · Midland Basin · earthquake rate