Inversion of source parameters for induced earthquakes in Groningen and surrounding small gas fields

Abstract

Source parameters of earthquakes provide valuable information in order to understand where the event occurred and what happened on the acting fault. This information can help to better understand why an area is prone to seismicity. We present a research earthquake catalogue between January 2016 and February 2025 for the induced seismicity in the Groningen gas field and a string of surrounding gas fields that are used for either production or storage. The earthquake catalogue is a list of relocated hypocentres, stress drops, seismic moments, moment magnitudes and moment tensor solutions with uncertainties. The updated list of hypocentres indicates that induced earthquakes in the Groningen field and surrounding gas fields have occurred in the reservoir. The general fault type is normal faulting with some strike-slip movement. The strike directions align well with known faults at the reservoir level. The stress drops generally increase with local magnitude. Some events with a local magnitude above 1.8 have stress drops up to 50–70 bar.