Oh, I am stunned. For the first time in my life I have seen earthquakes plotted together with injection wells, and volumes. Oh Glory Be!
If you click on the 'larger map' you will see that most of the wells are 25,000 barrel a day monsters. But take note that none are near Azle. This makes them issue the statement that there is no correlation. Saints be praised! They have tapped into what I was hoping for - a rock artery NW-SE. They will inject till the cows come home.
Plus, we have the fact that these earthquakes aren't properly located, probably a 10 km error bar. I really think these guys are my hope for an M4. The foundations will crack then!