Earthquake Growth Inhibited at Higher Coulomb Stress Change Rate at Groningen

Gas extraction from the Groningen gas field resulted in significant induced seismicity. We analyze the magnitude-frequency distribution of these earthquakes in space, time and in view of stress changes calculated based on gas production and reservoir properties. Previous studies suggested variations related to reservoir geometry and stress. While we confirm the spatial variations, we do not detect a clear sensitivity of b-value to Coulomb stress changes. However, we find that b-value correlates positively with the rate of Coulomb stress changes. This correlation is statistically significant and robust to uncertainties related to stress change calculation. This study thus points to a possible influence of stress change rate on the probability of the magnitude of induced earthquakes. Gas extraction from an underground reservoir in the Netherlands has induced significant seismicity. We analyze how stress changes and the rate of stress changes influence the magnitude of these earthquakes. We find that more smaller earthquakes tend to occur at higher stress change rates. Earthquakes triggered at a lower stress change rate may thus grow to larger magnitudes than those triggered at high stress change rate. This observation is statistically significant and independent of the method used to calculate stress change. We report a positive correlation between the b-value and the rate of Coulomb stress change of induced earthquakes in Groningen This trend is statistically significant and robust to changes in the mechanical model used to calculate the stress changes We interpret earthquake growth inhibition through a decrease of nucleation lengths at high stress change rates