Seismologists largely attribute widespread earthquakes in southern Kansas and northern Oklahoma to the injection-disposal of oil field brine deep into Earth’s crust. Recently, however, the frequency of earthquakes has increased significantly in areas of Kansas well beyond the initial high-seismicity zones near injection wells.
Because the vast majority of high-volume injection wells in the region are near and south of its border with Oklahoma, Kansas has a unique vantage point for observing far-field effects of injection.
Recent measurements show that subsurface fluid pressures are elevated across south central Kansas, including areas where injection practices have been relatively consistent for decades. The findings suggest that the cumulative effects of high-volume injection to the south have had an extended influence on fluid pressure in the pores of subsurface rocks.

This regional pressure change has the potential to trigger earthquakes far from the high-volume injection points, especially in areas where fluid pressure may already be elevated from local injection operations. (full article)

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