Abstract
Understanding the risk associated with anthropogenic earthquakes is essential in the development and management of engineering processes and hydraulic infrastructure that may alter pore pressures and stresses at depth. The possibility of earthquakes triggered by reservoir impoundment, ocean tides, and hydrological events at the Earth surface (hydro-seismicity) has been extensively debated. The link between induced seismicity and hydrological events is currently based on statistical correlations rather than on physical mechanisms. Here, we explore the geomechanical conditions that could allow for small pore pressure changes due to reservoir management and sea level changes to propagate to depths that are compatible with earthquake triggering at critically-stressed faults (several kilometers). We consider a damaged fault zone that is embedded in a poroelastic rock matrix, and conduct fully coupled hydromechanical simulations of pressure diffusion and rock deformation. We characterize the hydraulic and geomechanical properties of fault zones that could allow for small pressure and loading changes at the ground surface (in the order of tens or hundreds of kPa) to propagate with relatively small attenuation to seismogenic depths (up to 10 km). We find that pressure diffusion to such depths is only possible for highly permeable fault zones and/or strong poroelastic coupling.
Highlights
The recent increase in anthropogenic earthquakes [1], especially those that are linked to industrial activities and energy technologies [2,3], has recently attracted industrial, social and scientific interest.The role of pore fluid on the occurrence, spatial distribution, and magnitude of earthquakes has become a central scientific issue
It is essential to explore the geomechanical conditions that could allow small pore pressure changes to propagate to depths that are compatible with earthquake triggering at critically-stressed faults given that the link between induced seismicity and hydrological events is currently based on statistical evidence rather than on physical mechanisms
We analyze the effect of tidal oscillations on pore pressure changes along a strike-slip fault through two models
Summary
The recent increase in anthropogenic earthquakes [1], especially those that are linked to industrial activities and energy technologies [2,3], has recently attracted industrial, social and scientific interest. It is essential to explore the geomechanical conditions that could allow small pore pressure changes to propagate to depths that are compatible with earthquake triggering at critically-stressed faults (several kilometers) given that the link between induced seismicity and hydrological events is currently based on statistical evidence rather than on physical mechanisms. The system is subjected to periodical tidal actions at the surface (periodic changes in pore pressure and total vertical stress) These cause variations in both the pressure field and effective stresses along the fault, so that the fault permeability may play a significant role in the pressure diffusion. The poroelastic coupling emerges as a fault weakening factor, even when the fault permeability is rather low
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
