Hydro-fracturing and rock mechanics

Earthquakes attributable to human activities are called induced seismic events or induced earthquakes. In the past several years induced seismic events related to energy development projects have drawn heightened public attention. Induced seismicity associated with fluid injection or withdrawal is caused in most cases by change in pore fluid pressure and/or change in stress in the subsurface in the presence of faults with specific properties and orientations and a critical state of stress in the rocks. The aim of this program would be to along two fronts. On one end we would be modeling mechanical, permeability and pore pressure changes in a fractured medium surrounding a wastewater injection site and understand its role in triggering earthquake ruptures in a neighboring fault. 

On the second front we look at the induced - as well as triggerred - seismicity data in the theoretical framework of seismic source physics. For a given source, moment magnitudes and accurate hypocentre relocation are basic characteristics to be defined, but also does stress and source size. Then, spatio-temporal characteristics and magnitude distributions of seismicity shall be defined to constrain interevent correlation functions, bringing valuable information on the mechanical processes forcing the seismicity. Exotic seismic events, like low frequency earthquakes and tremors, as well as episodic creep or pore pressure instabilities will be part of the global picture for better defining the seismic/aseismic interactions and possible evolution of a system.

Contact: Bernard, Bhat, Noble