%0 Journal Article
%@ 00948276
%A Staszek, Monika
%A Orlecka-Sikora, Beata
%A Leptokaropoulos, Konstantinos Michail
%A Kwiatek, Grzegorz
%A Martinez-Garzon, Patricia
%A Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland,
%A Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland,
%A Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland,
%A Section 4.2: Geomechanics and Rheology, Helmholtz-Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany,
%A Section 4.2: Geomechanics and Rheology, Helmholtz-Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany,
%D 2017
%F epos:1994
%I Geophysical Research Letters
%J Geophysical Research Letters
%N 14
%P 7168-7176
%T Temporal static stress drop variations due to injection activity at The Geysers geothermal field, California
%U https://episodesplatform.eu/eprints/1994/
%V 44
%X We use a high-quality data set from the NW part of The Geysers geothermal field to determine  statistical significance of temporal static stress drop variations and their relation to injection rate changes.  We use a group of 322 seismic events which occurred in the proximity of Prati-9 and Prati-29 injection wells to  examine the influence of parameters such as moment magnitude, focal mechanism, hypocentral depth, and  normalized hypocentral distances from open-hole sections of injection wells on static stress drop changes.  Our results indicate that (1) static stress drop variations in time are statistically significant, (2) statistically  significant static stress drop changes are inversely related to injection rate fluctuations. Therefore, it is highly  expected that static stress drop of seismic events is influenced by pore pressure in underground fluid  injection conditions and depends on the effective normal stress and strength of the medium.