In Oklahoma, since 2009 there has been a sharp increase in earthquakes brought about by the use of waste water injection wells used by fracking companies as they conduct High Volume Hydraulic Fracturing (HVHF), other wise known as Unconventional Shale Gas Extraction (USGE), or fracking.
However, the US Geological Survey decided to investigate historical earthquake data for the state of Oklahoma and found that there have been induced (man-made) earthquakes that were caused by the process of waste water well injection practices dating back to the 1920’s
This is not to say that Unconventional Shale Gas Extraction was responsible for these historical earthquakes, for that particular process of shale gas extraction did not exist back then.
However, waste water injection wells are used in the current USGE process to store waste water from fracking underground. Waste water injection wells have been found to create earthquakes today. It has now been found that they have done so since the 1920’s.
The new study shows that: “it is possible that earthquakes were induced by oil production activities in Oklahoma as early as the 1920s, and several lines of evidence support our conclusion that much of the earthquake activity in the 1950s and 1980–1990s was induced.”
The study also states that earthquake activity since 2009 is: “not consistent with the level of natural rate fluctuations seen in the past.”
The study shows that earthquakes from the 1950’s correlated with oil and gas permits granted at the time, and near the location.
Key findings of the report include:
- seismicity rates since 2009 surpass previously observed rates throughout the twentieth century.
- Several lines of evidence suggest that most of the significant earthquakes in Oklahoma during the twentieth century were likely induced by oil production activities, as they exhibit statistically significant temporal and spatial correspondence with disposal wells, and intensity measurements for the 1952 El Reno earthquake and possibly the 1956 Tulsa County earthquake follow the pattern observed in other induced earthquakes.
- There is evidence for a low level of tectonic seismicity in southeastern Oklahoma associated with the Ouachita structural belt. The 22 October 1882 Choctaw Nation earthquake, for which we estimate Mw 4.8, occurred in this zone.
As we discussed before, Unconventional Shale Gas Extraction has been officially linked with man made earthquakes due to the use of waste water injection wells.