Friday, September 29, 2023 at 10:30am CT
Speaker: Eric Dunham, Professor, Department of Geophysics, Director, SDSS Center for Computation, Stanford University
Host: Demian Saffer
Title: Earthquake Swarms, Slow Slip, and Fault Valving in Coupled Models of Earthquakes and Fault Zone Fluid Transport
Abstract: Fluids and changes in pore fluid pressure in fault zones are thought to affect earthquake occurrence and fault slip behavior. Here we integrate fault zone fluid transport into earthquake cycle models to explore the coupled evolution of slip, pore fluid pressure, and fluid transport properties. We explore several models that account for the evolution of porosity and permeability in response to dilatancy, permeability enhancement during slip, chemical healing and sealing, and creep compaction. We also model the pore fluid pressure distribution along subduction megathrust faults by integrating petrologic modeling of dehydration reactions with mechanical modeling of up-dip fluid flow. The models produce fluid-driven aseismic slip, even for rate-strengthening friction, with many similarities to slow slip events, as well as swarm seismicity. We explore the relevance of these models to observations of slow slip events in subduction zones and to earthquake swarms (both naturally occurring and from injection), while also highlighting the need for additional experimental and geologic constraints to discriminate between the models.