[S02-2] World overview of anthropogenic seismicity II

[S02-2-02] Hydrocarbon induced seismicity in Groningen, the Netherlands

^○Bernard Dost, Elmer Ruigrok, Jesper Spetzler (KNMI, de Bilt, the Netherlands)

Since 2003 the dominant source of induced seismicity in the Netherlands is the Groningen gas field, one of the largest on-shore gas fields in the world. Due to the shallow source depth, at 3 km, even small magnitude events cause damage to buildings in the region. In 2012 the largest event, Ml 3.6, took place and more than 50000 damage claims were received by the mining company. Since 1995 a regional monitoring network is in operation, which has recently been extended over the Groningen field. Presently, more than 75 borehole strings with a maximum depth of 200 m and 90 surface accelerometers are operational. Since 2003 a new mining law is in place in the Netherlands, which requires for each gas field in production a seismic hazard and risk analysis. At the same time an increase in the activity rate was observed in the Groningen field, leading to the development of new hazard models and a re-assessment of parameters like the maximum magnitude. Understanding the earthquake process is essential in taking mitigation measures. Continued research is focused on reducing the uncertainties in the hazard and risk models. Key issues are the development of a site specific Ground Motion Model, improving the location accuracy of events, magnitude scaling and construction of a local shallow shear-wave velocity and Q model.