Reservoir pressure and earthquake rates in Groningen

An interim report updating continuing research into the frequency of earthquakes in Groningen, related to variations in the gas pressure inside the reservoir, commissioned by State Supervision of Mines.
This report is a continuation of research, commenced in 2014, which is part of a research project being carried out by Statistics Netherlands and commissioned by State Supervision of Mines (SodM). This research is part of the underpinning of the statistical methods employed to support the protocol for measurement and control of the production
of natural gas in the province of Groningen. In this research the particular focus is on the relationship between reservoir gas pressure variations and the earth quakes in Groningen.
From the analysis it is clear that there is a correlation, in the sense that prior to earthquakes there is an enhanced
signal in the reservoir gas pressure at the location of the earthquake. This is a re-analysis which is carried out because of the availability of improved, daily cadence, time series for the reservoir gas pressure. Also, use is made of improved localisation of a subset of earthquakes in the KNMI catalogue after re-analysis of the relevant seismometer traces.