Variations of b-values in Gutenberg-Richter’s law has been proven to provide insights on earthquake triggering mechanisms. These b-value variations express changes in the rate of occurrence of small earthquakes relative to large ones. Geophysical processes correlated with b-value variations have been identified using earthquake catalogues over natural tectonically active environments. Not so much is known over anthropogenic exploration sites due to the lack of dedicated seismometers in place and therefore the reduced number of recorded events. In the early 1990's, nearly after 30 years of gas production, small seismic events started to be detected at the Groningen gas field. Several efforts to measure these seismic events let to a unique seismic network and an earthquake catalogue available through KNMI’s website. We perform a temporal, spatial and spatiotemporal b-value analysis for which we use 800 events from early 90’s up to now with a magnitude lower limit of 1.1 (magnitude of completeness).@en