UC Berkeley

Earthquakes influence hydrogeological processes and properties in Earth's crust, some of which affect surface waters. We document increased discharge in a stream after the 3 September 2016 Mw 5.8 earthquake near Pawnee, Oklahoma, an event likely induced by underground wastewater disposal. Discharge increased by an order of magnitude and remained elevated until the change was obscured by rain 1 week later. Given the earthquake magnitude and distance from the stream, by comparison with previous examples of responses to earthquakes, increased discharge after this earthquake is expected. While the mechanism increasing discharge cannot be confirmed, the observations require changes in physical properties of the subsurface. Fluid injection may thus influence hydrogeological properties of shallow groundwater systems and aquifers indirectly by inducing seismicity, if the induced seismic events are large enough.