TY  - JOUR
A1  - Kwiatek, Grzegorz
A1  - Saarno, Tero
A1  - Ader, Thomas
A1  - Blümle, Felix
A1  - Bohnhoff, Marco
A1  - Chendorain, Michael
A1  - Dresen, Georg
A1  - Heikkinen, Pekka
A1  - Kukkonen, Ilmo
A1  - Leary, Peter
A1  - Leonhardt, Maria
A1  - Malin, Peter
A1  - Martinez-Garzon, Patricia
A1  - Passmore, Kevin
A1  - Passmore, Paul
A1  - Valenzuela, Sergio
A1  - Wollin, Christopher
T1  - Controlling fluid-induced seismicity during a 6.1-km-deep geothermal stimulation in Finland
JF  - Science Advances
N2  - We show that near-real-time seismic monitoring of fluid injection allowed control of induced earthquakes during the stimulation of a 6.1-km-deep geothermal well near Helsinki, Finland. A total of 18,160 m(3) of fresh water was pumped into crystalline rocks over 49 days in June to July 2018. Seismic monitoring was performed with a 24-station borehole seismometer network. Using near-real-time information on induced-earthquake rates, locations, magnitudes, and evolution of seismic and hydraulic energy, pumping was either stopped or varied-in the latter case, between well-head pressures of 60 and 90 MPa and flow rates of 400 and 800 liters/min. This procedure avoided the nucleation of a project-stopping magnitude M-W 2.0 induced earthquake, a limit set by local authorities. Our results suggest a possible physics-based approach to controlling stimulation-induced seismicity in geothermal projects.
Y1  - 2019
U6  - https://doi.org/10.1126/sciadv.aav7224
SN  - 2375-2548
VL  - 5
IS  - 5
PB  - American Association for the Advancement of Science
CY  - Washington
ER  - 
TY  - JOUR
A1  - Durand, Virginie
A1  - Bentz, Stephan
A1  - Kwiatek, Grzegorz
A1  - Dresen, Georg
A1  - Wollin, Christopher
A1  - Heidbach, Oliver
A1  - Martinez-Garzon, Patricia
A1  - Cotton, Fabrice
A1  - Nurlu, Murat
A1  - Bohnhoff, Marco
T1  - A two-scale preparation phase preceded an M-w 5.8 earthquake in the sea of marmara offshore Istanbul, Turkey
JF  - Seismological research letters
N2  - We analyze the spatiotemporal evolution of seismicity during a sequence of moderate (an M-w 4.7 foreshock and M-w 5.8 mainshock) earthquakes occurring in September 2019 at the transition between a creeping and a locked segment of the North Anatolian fault in the central Sea of Marmara, northwest Turkey. To investigate in detail the seismicity evolution, we apply a matched-filter technique to continuous waveforms, thus reducing the magnitude threshold for detection. Sequences of foreshocks preceding the two largest events are clearly seen, exhibiting two different behaviors: a long-term activation of the seismicity along the entire fault segment and a short-term concentration around the epicenters of the large events. We suggest a two-scale preparation phase, with aseismic slip preparing the mainshock final rupture a few days before, and a cascade mechanism leading to the nucleation of the mainshock. Thus, our study shows a combination of seismic and aseismic slip during the foreshock sequence changing the strength of the fault, bringing it closer to failure.
Y1  - 2020
U6  - https://doi.org/10.1785/0220200110
SN  - 0895-0695
SN  - 1938-2057
VL  - 91
IS  - 6
SP  - 3139
EP  - 3147
CY  - Boulder
ER  -