A geophysics professor details the foreshock activities leading up to the Pawnee earthquake, and highlights the complicated relationship between seismicity and wastewater injection rates in a research study. The study details the precursory earthquake (foreshock) sequences that culminated in the September 3, 2016, 5.8 magnitude earthquake near Pawnee, Okla., which ruptured along the previously unmapped Sooner Lake Fault.