Confirming b-value spatial variations in Groningen gas field using machine-learning-derived seismic data

Abstract

The Groningen gas field is Europe’s largest onshore reservoir. Continuous production between 1963 and 2024 has driven reservoir compaction and subsidence, progressively loading pre-existing faults and inducing earthquakes. Recently examined spatio-temporal variations of the Gutenberg–Richter b-value, a proxy for differential stress, across the field, mapping persistent low-b regions in the north and documenting a decade-long trend towards spatial homogeneity closely related to production.

This study revisits Gulia’s results by integrating the original Royal Netherlands Meteorological Institute (RNMI) dataset with the enhanced earthquake catalogue of which newly identifies 660 events and reveals non-clustered and swarm behaviours amongst induced seismicity. The combined/improved catalogue allows to better capture recent trends coinciding with reduced extraction rates and a shift in production towards the south. The aim of this work is to evaluate whether the patterns and hypotheses proposed remain consistent considering the enhanced dataset and to update the analysis with the most recent data. We also evaluate the impact on the evolution of the b-value in the probability of larger events, finding that the continued decrease in b-value compensates for the decrease in seismic activity.