scholarly journals A Systematic Assessment of the Spatiotemporal Evolution of Fault Activation Through Induced Seismicity in Oklahoma and Southern Kansas

2017 ◽  
Vol 122 (12) ◽  
pp. 10,189-10,206 ◽  
Author(s):  
Martin Schoenball ◽  
William L. Ellsworth
Keyword(s):  
Induced Seismicity ◽  
Spatiotemporal Evolution ◽  
Systematic Assessment ◽  
Fault Activation

A Novel Coupled Approach to Investigate the Spatiotemporal Evolution of Fracturing-Induced Seismicity: Case Study

2021 ◽  
Author(s):  
Gang Hui ◽  
Shengnan Chen ◽  
Fei Gu
Keyword(s):  
Hydraulic Fracturing ◽  
Induced Seismicity ◽  
Spatiotemporal Pattern ◽  
Hydraulic Fractures ◽  
Spatiotemporal Evolution ◽  
Coupled Flow ◽  
Seismicity Rate ◽  
Failure State ◽  
Pkn Model

Abstract The recent seismicity rate increase in Fox Creek is believed to be linked to the hydraulic fracturing operations near the region. However, the spatiotemporal evolution of hydraulic fracturing-induced seismicity is not well understood. Here, a coupled approach of geology, geomechanics, and hydrology is proposed to characterize the spatiotemporal evolution of hydraulic fracturing-induced seismicity. The seismogenic faults in the vicinity of stimulated wells are derived from the focal mechanisms of mainshock event and lineament features of induced events. In addition, the propagation of hydraulic fractures is simulated by using the PKN model, in combination with inferred fault, to characterize the possible well-fault hydrological communication. The original stress state of inferred fault is determined based on the geomechanics analysis. Based on the poroelasticity theory, the coupled flow-geomechanics simulation is finally conducted to quantitatively understand the fluid diffusion and poroelastic stress perturbation in response to hydraulic fracturing. A case study of a moment-magnitude-3.4 earthquake near Fox Creek is utilized to demonstrate the applicability of the coupled approach. It is shown that hydraulic fractures propagated along NE45° and connected with one North-south trending fault, causing the activation of fault and triggered the large magnitude event during fracturing operations. The barrier property of inferred fault under the strike-slip faulting regime constrains the nucleation position of induced seismicity within the injection layer. The combined changes of pore pressure and poroelastic stress caused the inferred fault to move towards the failure state and triggered the earthquake swarms. The associated spatiotemporal changes of Coulomb Failure Stress along the fault plane is well in line with the spatiotemporal pattern of induced seismicity in the studied case. Risks of seismic hazards could be reduced by decreasing fracturing job size during fracturing stimulations.

scholarly journals Fault activation and induced seismicity in geological carbon storage – Lessons learned from recent modeling studies

2016 ◽  
Vol 8 (6) ◽  
pp. 789-804 ◽  
Author(s):  
Jonny Rutqvist ◽  
Antonio P. Rinaldi ◽  
Frederic Cappa ◽  
Pierre Jeanne ◽  
Alberto Mazzoldi ◽  
...  
Keyword(s):  
Carbon Storage ◽  
Induced Seismicity ◽  
Lessons Learned ◽  
Fault Activation ◽  
Modeling Studies

Stochastic modelling of injection-induced seismicity in the Cooper Basin enhanced geothermal system

2021 ◽  
Author(s):  
Georgios Michas ◽  
Filippos Vallianatos
Keyword(s):  
Diffusion Equation ◽  
Induced Seismicity ◽  
Heterogeneous Media ◽  
Fractional Diffusion ◽  
Fractional Diffusion Equation ◽  
Geothermal System ◽  
Nonlinear Transport ◽  
Spatiotemporal Evolution ◽  
Time Fractional Diffusion Equation ◽  
Cooper Basin

<p>Fluid-injections under high pressures into deep “hot” rock formations are routinely performed during the development of Enhanced Geothermal Systems (EGS). Such fluid-injections, which aim to enhance the permeability in the targeted rock formation, can induce intense microseismicity and in some cases even larger magnitude earthquakes. A characteristic of injection-induced seismicity is its spatial migration with time, which is considered indicative of pore-pressure diffusion and the geometry of the stimulated volume in which permeability is enhanced. Understanding the details of earthquake migration during stimulation operations is particularly important for the design of EGS, the management of operations, as well as for the mitigation of hazardous induced earthquakes. Herein, we develop a stochastic model to map the spatiotemporal evolution of injection-induced seismicity. The model is based on the well-established Continuous Time Random Walk (CTRW) theory that has widely been applied in nonlinear transport phenomena in complex heterogeneous media. Within this context, we describe the spatiotemporal evolution of injection-induced seismicity with an appropriate master equation and the time-fractional diffusion equation. Application of the model to two stimulation experiments in the Cooper Basin (Australia) EGS shows that induced seismicity migrates slowly with time away from the injection points according to a subdiffusive process, with waiting times between the successive earthquakes drawn from a broad probability density function with asymptotic power-law behavior. Moreover, we show that the solution of the time-fractional diffusion equation adequately describes the propagation of induced seismicity in time and space, showing a peak of earthquake concentration close to the injection point and a stretched exponential decay for the concentration of distant events. The results demonstrate that the CTRW model can efficiently describe nonlinear diffusion of injection-induced seismicity during stimulation operations in EGS.       </p><p><strong>Acknowledgements</strong></p><p>The research project was supported by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the “2nd Call for H.F.R.I. Research Projects to support Post-Doctoral Researchers” (Project Number: 00256).</p>

Reassessment of Suicide Attempters at Home, Shortly After Discharge from Hospital

Crisis ◽  
2010 ◽  
Vol 31 (6) ◽  
pp. 303-310 ◽  
Author(s):  
Bas Verwey ◽  
Jeroen A. van Waarde ◽  
Molla A. Bozdağ ◽  
Iris van Rooij ◽  
Edwin de Beurs ◽  
...  
Keyword(s):  
Suicide Attempt ◽  
General Hospital ◽  
Hospital Environment ◽  
Initial Assessment ◽  
Suicide Attempters ◽  
Systematic Assessment ◽  
Suicide Intent ◽  
Initial Hospital ◽  
Discharge From Hospital ◽  
At Home

Background: Assessment of suicide attempters in a general hospital may be influenced by the condition of the patient and the unfavorable circumstances of the hospital environment. Aims: To determine whether the results of a reassessment at home shortly after discharge from hospital differ from the initial assessment in the hospital. Methods: In this prospective study, systematic assessment of 52 suicide attempters in a general hospital was compared with reassessment at home, shortly after discharge. Results: Reassessments at home concerning suicide intent, motives for suicide attempt, and dimensions of psychopathology did not differ significantly from the initial hospital assessment. However, patients’ motives for the suicide attempt had changed to being less impulsive and more suicidal, worrying was significantly higher, and self-esteem was significantly lower. A third of the patients had forgotten their aftercare arrangements and most patients who initially felt no need for additional help had changed their mind at reassessment. Conclusions: Results from this group of suicide attempters suggest that a brief reassessment at home shortly after discharge from hospital should be considered.

Varied Responses to Human-Induced Seismicity in the City of Azle, Texas

2019 ◽  
Vol 3 (1) ◽  
pp. 1-8
Author(s):  
Sarmistha R. Majumdar
Keyword(s):  
State Government ◽  
Induced Seismicity ◽  
Oil And Gas ◽  
The United States ◽  
The State ◽  
Prior History ◽  
Small Community ◽  
Regulatory Policies ◽  
The Status

Fracking has helped to usher in an era of energy abundance in the United States. This advanced drilling procedure has helped the nation to attain the status of the largest producer of crude oil and natural gas in the world, but some of its negative externalities, such as human-induced seismicity, can no longer be ignored. The occurrence of earthquakes in communities located at proximity to disposal wells with no prior history of seismicity has shocked residents and have caused damages to properties. It has evoked individuals’ resentment against the practice of injection of fracking’s wastewater under pressure into underground disposal wells. Though the oil and gas companies have denied the existence of a link between such a practice and earthquakes and the local and state governments have delayed their responses to the unforeseen seismic events, the issue has gained in prominence among researchers, affected community residents, and the media. This case study has offered a glimpse into the varied responses of stakeholders to human-induced seismicity in a small city in the state of Texas. It is evident from this case study that although individuals’ complaints and protests from a small community may not be successful in bringing about statewide changes in regulatory policies on disposal of fracking’s wastewater, they can add to the public pressure on the state government to do something to address the problem in a state that supports fracking.

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