Groos, J.

Grund, M.

Ritter, J.

Zeiß, J.

KITopen

Geophysical Research AbstractsVol. 15, EGU2013-2742, 2013EGU General Assembly 2013© Author(s) 2013. CC Attribution 3.0 License.Microseismicity at two geothermal power plants at Landau and Insheimin the Upper Rhine Graben, GermanyJörn Groos, Jens Zeiß, Michael Grund, and Joachim RitterKarlsruhe Institute of Technology (KIT), Geophysical Institute, Karlsruhe, Germany (joern.groos@kit.edu)The Upper Rhine Graben in south-western Germany and especially the southern part of Rhineland-Palatinate isone of the regions with the highest potential for deep geothermal power generation in Germany. One geothermalpower plant is operated since 2007 in the city of Landau and a second power plant since Oct. 2012 near Insheim(∼4 km south-east of Landau). Further geothermal power plants are currently projected in this region. In 2009 twoearthquakes with magnitudes (ML) of 2.4 and 2.7 occurred in direct vicinity of the geothermal reservoir belowLandau (depth ∼3 km) and were felt within a radius of several kilometres (intensity up to V+). Furthermore,two felt earthquakes with magnitudes (ML) of 2.2 and 2.4 occurred during the stimulation of the reservoir nearInsheim in April 2010. Therefore, a temporary seismic network was deployed and is continuously extended by theGeophysical Institute of the Karlsruhe Institute of Technology with 12 stations (surface and shallow borehole) ofthe KArlsruhe Broad Band Array KABBA. In total more than 35 stations are operated by four operators for themicroseismic monitoring of the region around Landau.The main challenge of the monitoring is the detection of the microseismic events with a magnitude MLbelow 1 due to the high seismic noise conditions in the densely populated Upper Rhine Graben. The application ofestablished short-term to long-term average trigger algorithms is not feasible due to the large amount of transientsignals caused by human activity (e.g. traffic). We apply an automated detection of microseismic events based ona combined cross-correlation and correlation coefficient analysis with known seismic events. The detected eventsare localized for absolute (HYPOSAT) and relative (hypoDD) hypocentres. Furthermore, we determine the peakground velocities and vibration intensities after the German standard (DIN 4150-2 Structural vibration: humanexposure to vibration in buildings) to evaluate the perceptibility of the shallow seismic events with ML<2.Up to now (Dec. 2012) more than 600 microseismic events (-0.5 < ML < 2.7; 2009-2012) could be de-tected which are related to the geothermal reservoirs below Landau and Insheim. The events occurred duringcirculation (Landau, 2009-2012; Insheim since Oct. 2012) as well as stimulation (Insheim, April 2010). For bothreservoirs we observe clusters of earthquakes with highly similar waveforms (correlation coefficient larger than0.9) which indicate a repeated occurrence of microseismic events with similar focal mechanisms and hypocenters.At Landau the earthquakes are located north-west and close to the landing point of the injection well. Thecomparison of event magnitudes, measured peak ground velocities (PGV) and the obtained maximum vibrationintensities indicates that shallow (2-4 km) seismic events as weak as ML ∼1.3-1.5 can be felt by the population inLandau.This study is part of the research project MAGS (Microseismic Activity of Geothermal Systems) which isfunded by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety of the FederalRepublic of Germany (FKZ 0325191A-F) and supervised by Projektträger Jülich (PT-J).

Microseismicity at two geothermal power plants at Landau and Insheim in the Upper Rhine Graben, Germany

https://publikationen.bibliothek.kit.edu/1000051807/25900664

Microseismicity at two geothermal power plants at Landau and Insheim in the Upper Rhine Graben, Germany

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