Seismicity scenarios for the remaining operating period of the gas field in Groningen, Netherlands

In recent years, induced seismicity at the Groningen gas field caused increasing public concern and became a critical factor for future gas production plans. Zoeller and Holschneider (2016) estimated the upper bound of the 90% confidence interval for the maximum possible magnitude based on the earthquake catalog until 2016 and found M 4.4. In this study, we show that the updated estimate for earthquake activity until 2022 decreases to M 4.0. For the 95% confidence interval, the upper bound that was infinite for the catalog until 2016 decreases to the value M 4.2 for the updated catalog. Because the frequency-magnitude distribution is stable within the uncertainties, it is likely that the growth of the earthquake catalog since 2016 has led to decreasing uncertainties and thus to smaller confidence intervals. Second, we find that a model based on rate-and-state dependent friction with additional aftershocks fits the available data well. Despite the overall decreasing earthquake rate resulting from decreasing production volumes, scenario calculations based on simulated pressure and compaction data indicate a considerable probability that the maximum expected magnitude in the next 30 yr exceeds the maximum observed magnitude from the past 30 yr.