%0 Journal Article %1 bachmann_etal:2012 %A Bachmann, C. E. %A Wiemer, S. %A Goertz-Allmann, B. P. %A Woessner, J. %D 2012 %J Geophysical Research Letters %K geophysics seismology %N 9 %P L09302+ %R 10.1029/2012GL051480 %T Influence of pore-pressure on the event-size distribution of induced earthquakes %U http://dx.doi.org/10.1029/2012GL051480 %V 39 %X During an Enhanced Geothermal System (EGS) experiment, fluid is injected at high pressure into crystalline rock, to enhance its permeability and thus create a reservoir from which geothermal heat can be extracted. The fracturing of the basement caused by these high pore-pressures is associated with microseismicity. However, the relationship between the magnitudes of these induced seismic events and the applied fluid injection rates, and thus pore-pressure, is unknown. Here we show how pore-pressure can be linked to the seismic frequency-magnitude distribution, described by its slope, the b-value. We evaluate the dataset of an EGS in Basel, Switzerland and compare the observed event-size distribution with the outcome of a minimalistic model of pore-pressure evolution that relates event-sizes to the differential stress sigmaD. We observe that the decrease of b-values with increasing distance of the injection point is likely caused by a decrease in pore-pressure. This leads to an increase of the probability of a large magnitude event with distance and time.

@article{bachmann_etal:2012, abstract = {During an Enhanced Geothermal System (EGS) experiment, fluid is injected at high pressure into crystalline rock, to enhance its permeability and thus create a reservoir from which geothermal heat can be extracted. The fracturing of the basement caused by these high pore-pressures is associated with microseismicity. However, the relationship between the magnitudes of these induced seismic events and the applied fluid injection rates, and thus pore-pressure, is unknown. Here we show how pore-pressure can be linked to the seismic frequency-magnitude distribution, described by its slope, the b-value. We evaluate the dataset of an EGS in Basel, Switzerland and compare the observed event-size distribution with the outcome of a minimalistic model of pore-pressure evolution that relates event-sizes to the differential stress sigmaD. We observe that the decrease of b-values with increasing distance of the injection point is likely caused by a decrease in pore-pressure. This leads to an increase of the probability of a large magnitude event with distance and time.}, added-at = {2012-09-01T13:08:21.000+0200}, author = {Bachmann, C. E. and Wiemer, S. and Goertz-Allmann, B. P. and Woessner, J.}, biburl = {https://www.bibsonomy.org/bibtex/2a7ec593776ff5008b7b72930b7bef82a/nilsma}, day = 2, doi = {10.1029/2012GL051480}, interhash = {65600205ffccb48ad9015359803782b9}, intrahash = {a7ec593776ff5008b7b72930b7bef82a}, issn = {0094-8276}, journal = {Geophysical Research Letters}, keywords = {geophysics seismology}, month = may, number = 9, pages = {L09302+}, timestamp = {2021-02-09T13:22:37.000+0100}, title = {Influence of pore-pressure on the event-size distribution of induced earthquakes}, url = {http://dx.doi.org/10.1029/2012GL051480}, volume = 39, year = 2012 }