Wastewater Disposal and the Earthquake Sequences During 2016 Near Fairview, Pawnee, and Cushing, Oklahoma

Abstract

Each of the three earthquake sequences in Oklahoma in 2016—Fairview, Pawnee, and Cushing—appears to have been induced by high‐volume wastewater disposal within 10 km. The Fairview M5.1 main shock was part of a 2 year sequence of more than 150 events of M3, or greater; the main shock accounted for about half of the total moment. The foreshocks and aftershocks of the M5.8 Pawnee earthquake were too small and too few to contribute significantly to the cumulative moment; instead, nearly all of the moment induced by wastewater injection was focused on the main shock. The M5.0 Cushing event is part of a sequence that includes 48 earthquakes of M3, or greater, that are mostly foreshocks. The cumulative moment for each of the three sequences during 2016, as well as that for the 2011 Prague, Oklahoma, and nine other sequences representing a broad range of injected volume, are all limited by the total volumes of wastewater injected locally.

Rupture Model of the M5.8 Pawnee, Oklahoma, Earthquake From Regional and Teleseismic Waveforms

“…The 3 September 2016 12:02:44 (UTC) M 5.8 earthquake near Pawnee, Oklahoma, ruptured the previously unmapped, northwest‐striking Sooner Lake fault and was the largest historically recorded earthquake in the state, exposing more than 70 k people to strong ground shaking, and causing light damage to structures in the vicinity (Clayton et al, ; U.S. Geological Survey PAGER, 2018; Yeck et al, ; Figure ). Numerous studies point to the injection of produced wastewater associated with oil and gas operations as a critical causative factor for the earthquake (e.g., Chen et al, ; McGarr & Barbour, ; Yeck et al, ). The earthquake is part of an unprecedented increase in seismicity rates in Oklahoma of more than two orders of magnitude compared to historical rates, owing to induced earthquakes (Ellsworth, ; Keranen et al, ; Llenos & Michael, ; Moschetti et al, ).…”

Temporal Correlation Between Seismic Moment and Injection Volume for an Induced Earthquake Sequence in Central Oklahoma

“…This is similar to the analysis conducted in McGarr and Barbour (), where they focused on the scaling between total seismic moment for the M 5 earthquake sequences in Oklahoma and injection volume within 10 km of each sequence, instead of maximum seismic moment. They reported scaling factor between 1 and 30 GPa and suggested that such variations maybe attributed to heterogeneity in shear modulus.…”

“…They reported scaling factor between 1 and 30 GPa and suggested that such variations maybe attributed to heterogeneity in shear modulus. The average scaling factor between and Δ V for the sequence here is about 13.5 GPa if assuming the relationship in McGarr () and McGarr and Barbour () or 27 GPa if assuming the relationship in McGarr (). The former suggests that the scaling factor is well within the range reported in McGarr and Barbour () and could be attributed to heterogeneity, while the latter suggests a possible role of elastic stress transfer with stress perturbations in the deviatoric stress field (McGarr, ).…”

“…The total injected volume from the three nearest wells is 7.1 × 10 5 m 3 , stemming mainly from well 1 with 4.1 × 10 5 m 3 . As discussed in McGarr and Barbour (), identifying spatial extents of injection wells that contribute to Δ V is challenging; however, they have found that 10‐km radius is generally reasonable for the M 5 earthquakes sequences that they analyzed. In this case, the 10‐km radius would rule out the higher rate disposal well Safari and most other wells.…”

Leakage and Increasing Fluid Pressure Detected in Oklahoma's Wastewater Disposal Reservoir

“…(right) Monthly injection volumes from all injection wells within 10 km of the monitoring well (highlighted in the map), in cubic meters; data are not available prior to 2014 or after 2017. For comparison, the dashed line shows the injection history within 10 km of the Pawnee mainshock (McGarr & Barbour, ), which includes a few wells in Osage County (Barbour et al, ); this ends abruptly because active wells were shut in following the mainshock.…”