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A new study examining seismicity in North Texas relies on questionable assumptions and contradictory claims to link earthquakes to injection operations, according to a review by Energy In Depth. The study (Hornbach et al., 2016), authored by researchers at Southern Methodist University and the University of Texas at Austin, claims it is “plausible” that injection operations triggered earthquakes near Irving, Tex., despite the fact that no injection wells are in the area.

It’s worth noting that this same team of researchers has published multiple reports on North Texas earthquakes. Notably, they collaborated last year for a study on seismic events near Azle, Tex., (Hornbach et al., 2015), as well as a study released earlier this year (Frohlich et al., 2016) that introduced a new “five question test” for assessing earthquake causality. Many of the authors are also part of the Center for Integrated Seismicity Research, including one who serves on the governor’s technical advisory committee.

To connect the Irving-Dallas earthquake sequence to injection, Hornbach et al. (2016) had to make assumptions about the geology of North Texas, many of which were flawed or even contradict what the authors themselves have found in previous studies. Below are a few of the most notable errors in the study, which raise questions about the validity of its conclusions.

From ‘Tremendous Heterogeneity’ to ‘Relative Homogeneity’

In Hornbach et al. (2016), the authors “assume relative homogeneity for the Ellenburger” to arrive at their conclusion. According to the study, that homogeneity allowed fluid pressures to travel up to 40 kilometers to trigger the Irving-Dallas earthquake sequence.

But last year, the same authors (Hornbach et al., 2015) stressed that “tremendous heterogeneity exists in the El...