TY  - JOUR
ID  - epos1930
UR  - http://doi.org/10.1002/2016GL071963
IS  - 2
A1  - Martinez-Garzon, Patricia
A1  - Kwiatek, Grzegorz
A1  - Bohnhoff, Marco
A1  - Dresen, Georg
Y1  - 2017/01//
N2  - We investigate source processes of fluid-induced seismicity from The Geysers geothermal reservoir in California to determine their relation with hydraulic operations and improve the corresponding seismic hazard estimates. Analysis of 869 well-constrained full moment tensors (Mw 0.8?3.5) reveals significant non-double-couple components (>25%) for about 65% of the events. Volumetric deformation is governed by cumulative injection rates with larger non-double-couple components observed near the wells and during high injection periods. Source mechanisms are magnitude dependent and vary significantly between faulting regimes. Normal faulting events (Mw?<?2) reveal substantial volumetric components indicating dilatancy in contrast to strike-slip events that have a dominant double-couple source. Volumetric components indicating closure of cracks in the source region are mostly found for reverse faulting events with Mw?>?2.5. Our results imply that source processes and magnitudes of fluid-induced seismic events are strongly affected by the hydraulic operations, the reservoir stress state, and the faulting regime.
PB  - American Geophysical Union
JF  - Geophysical Research Letters
VL  - 44
SN  - 0094-8276
TI  - Volumetric components in the earthquake source related to fluid injection and stress state
SP  - 800
AV  - none
EP  - 809
ER  -