scholarly journals Injection‐Induced Seismic Moment Release and Laboratory Fault Slip: Implications for Fluid‐Induced Seismicity

2020 ◽  
Vol 47 (22) ◽  
Author(s):  
Lei Wang ◽  
Grzegorz Kwiatek ◽  
Erik Rybacki ◽  
Marco Bohnhoff ◽  
Georg Dresen
Keyword(s):  
Seismic Moment ◽  
Induced Seismicity ◽  
Fault Slip ◽  
Seismic Moment Release

Fluid-induced Seismicity Depends on Injection Rate

2021 ◽  
Author(s):  
Georg Dresen ◽  
Lei Wang ◽  
Grzegorz Kwiatek ◽  
Erik Rybacki ◽  
Audrey Bonnelye ◽  
...  
Keyword(s):  
Release Rate ◽  
Seismic Moment ◽  
Injection Rate ◽  
Fault Slip ◽  
Fluid Injection ◽  
Fault Creep ◽  
Stick Slip ◽  
Pressurization Rate ◽  
Seismic Moment Release ◽  
Fluid Pressurization

<p>Fluid injection causes fault slip that is partitioned in aseismic and seismic moment release. EGS stimulation campaigns have shown that in addition to total fluid volume injected also the rates of injection and fluid pressure increase affect seismic moment release. We investigate the effect of injection rate on slip characteristics, strain partitioning and energy budget in laboratory fluid injection experiments on reservoir sandstone samples in a triaxial deformation apparatus equipped with a 16-channel acoustic emission (AE) recording system. We injected fluid in sawcut samples containing a critically stressed fault at different pressurization rates. In general, fluid-induced fault deformation is dominantly aseismic. We find slow stick-slip events are induced at high fluid pressurization rate while steady fault creep occurs in response to low fluid pressurization rate. The released total seismic moment is found to be related to total injected volume, independent of fault slip behavior. Seismic moment release rate of AE is related to measured fault slip velocity. Total potential energy change and fracture energy release rate are defined by fault stiffness and largely independent of injection rate. Breakdown power density scales with slip rate and is significantly higher for fast injection and pressurization rates. The relation between moment release and injected volume is affected by fault slip behavior, characterized by a linear relation for slip at constant rate and fault creep while a cubic relation is evident for unstable and dynamic slip. Our experimental results allow separating a stable pressure-controlled injection phase with low rate of energy dissipation from a run-away phase, where breakdown power is high and cumulative moment release with injected volume is non-linear.</p>

scholarly journals Precursory accelerating seismic moment release (AMR) in a synthetic seismicity catalog: A preliminary study

2005 ◽  
Vol 32 (7) ◽  
pp. n/a-n/a ◽  
Author(s):  
Russell Robinson ◽  
Shiyong Zhou ◽  
Steven Johnston ◽  
David Vere-Jones
Keyword(s):  
Seismic Moment ◽  
Preliminary Study ◽  
Seismicity Catalog ◽  
Seismic Moment Release

scholarly journals Slip distributions on active normal faults measured from LiDAR and field mapping of geomorphic offsets: an example from L'Aquila, Italy, and implications for modelling seismic moment release

Geomorphology ◽  
2015 ◽  
Vol 237 ◽  
pp. 130-141 ◽  
Author(s):  
Maxwell Wilkinson ◽  
Gerald P. Roberts ◽  
Ken McCaffrey ◽  
Patience A. Cowie ◽  
Joanna P. Faure Walker ◽  
...  
Keyword(s):  
Seismic Moment ◽  
Normal Faults ◽  
Field Mapping ◽  
Seismic Moment Release

scholarly journals Time-dependent Seismic Footprint of Thermal Loading for Geothermal Activities in Fractured Carbonate Reservoirs

2021 ◽  
Vol 9 ◽  
Author(s):  
B. B. T. Wassing ◽  
T. Candela ◽  
S. Osinga ◽  
E. Peters ◽  
L. Buijze ◽  
...  
Keyword(s):  
Seismic Response ◽  
Seismic Moment ◽  
Fracture Network ◽  
Carbonate Reservoir ◽  
Time Dependent ◽  
Seismicity Rates ◽  
Fractured Carbonate ◽  
Stress Environments ◽  
Seismic Moment Release ◽  
Frequency Magnitude

This paper describes and deploys a workflow to assess the evolution of seismicity associated to injection of cold fluids close to a fault. We employ a coupled numerical thermo-hydro-mechanical simulator to simulate the evolution of pressures, temperatures and stress on the fault. Adopting rate-and-state seismicity theory we assess induced seismicity rates from stressing rates at the fault. Seismicity rates are then used to derive the time-dependent frequency-magnitude distribution of seismic events. We model the seismic response of a fault in a highly fractured and a sparsely fractured carbonate reservoir. Injection of fluids into the reservoir causes cooling of the reservoir, thermal compaction and thermal stresses. The evolution of seismicity during injection is non-stationary: we observe an ongoing increase of the fault area that is critically stressed as the cooling front propagates from the injection well into the reservoir. During later stages, models show the development of an aseismic area surrounded by an expanding ring of high seismicity rates at the edge of the cooling zone. This ring can be related to the “passage” of the cooling front. We show the seismic response of the fault, in terms of the timing of elevated seismicity and seismic moment release, depends on the fracture density, as it affects the temperature decrease in the rock volume and thermo-elastic stress change on the fault. The dense fracture network results in a steeper thermal front which promotes stress arching, and leads to locally and temporarily high Coulomb stressing and seismicity rates. We derive frequency-magnitude distributions and seismic moment release for a low-stress subsurface and a tectonically active area with initially critically stressed faults. The evolution of seismicity in the low-stress environment depends on the dimensions of the fault area that is perturbed by the stress changes. The probability of larger earthquakes and the associated seismic risk are thus reduced in low-stress environments. For both stress environments, the total seismic moment release is largest for the densely spaced fracture network. Also, it occurs at an earlier stage of the injection period: the release is more gradually spread in time and space for the widely spaced fracture network.

Slow strain release along the eastern Marmara region offshore Istanbul in conjunction with enhanced local seismic moment release

2019 ◽  
Vol 510 ◽  
pp. 209-218 ◽  
Author(s):  
Patricia Martínez-Garzón ◽  
Marco Bohnhoff ◽  
David Mencin ◽  
Grzegorz Kwiatek ◽  
Georg Dresen ◽  
...  
Keyword(s):  
Seismic Moment ◽  
Marmara Region ◽  
Strain Release ◽  
Seismic Moment Release

Characteristics of induced seismicity during hydraulic stimulations

2020 ◽  
Author(s):  
Georg Dresen ◽  
Stephan Bentz ◽  
Grzegorz Kwiatek ◽  
Patricia Martínez-Garzón ◽  
Marco Bohnhoff
Keyword(s):  
Real Time ◽  
Seismic Moment ◽  
Induced Seismicity ◽  
Fluid Volume ◽  
Physical Models ◽  
Traffic Light ◽  
Induced Earthquakes ◽  
Induced Earthquake ◽  
Energy Pumping ◽  
Good Agreement

<p>Near-realtime seismic monitoring of fluid injection allowed control of induced earthquakes during the stimulation of a 6.1 km deep geothermal well near Helsinki, Finland. The stimulation was monitored in near-real time using a deep seismic borehole array and series of borehole stations. Earthquakes were processed within a few minutes and results informed a Traffic Light System (TLS). Using near-realtime information on induced-earthquake rates, locations, magnitudes, and evolution of seismic and hydraulic energy, pumping was either stopped or varied. This procedure avoided the nucleation of a project-stopping red alert at magnitude M2.1 induced earthquake, a limit set by the TLS and local authorities. Our recent studies show that the majority of EGS stimulation campaigns investigated reveal a clear linear relation between injected fluid volume, hydraulic energy and cumulative seismic moments suggesting extended time-spans during which induced seismicity evolution is pressure-controlled. For most projects studied, the observations are in good agreement with existing physical models that predict a relation between injected fluid volume and maximum seismic moment of induced events. Some EGS stimulations however reveal unbound increase in seismic moment suggesting that for these cases evolution of seismicity is mainly controlled by stress field, the size of tectonic faults and fault connectivity. Transition between the two states may occur at any time during injection, or not at all. Monitoring and traffic-light systems used during stimulations need to account for the possibility of unstable rupture propagation from the very beginning of injection by observing the entire seismicity evolution in near-real-time and at high resolution could possibly provide a successful physics-based approach in reducing seismic hazard from stimulation-induced seismicity in geothermal projects.</p>

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