Current Research in EEPS Seminar: Patrick Fulton – Texas A&M University
Abstract Title: Insights into Earthquake Physics from Heat and Fluids in Faults
Subsurface hydrogeologic processes and conditions can have a direct effect on the strength and stability of faults. Interestingly, in return, fault slip behavior can influence hydrogeologic properties and conditions. Here I discuss ongoing explorations of these relationships, by myself and colleagues, that are providing new insight into rapid yet silent stressers to fault zones.
For example, through a range of innovative thermal and hydrologic borehole monitoring and signal analysis techniques, along with numerical modeling and laboratory experimentation, we are able to characterize fault zone hydrogeologic properties over space and time and are gaining a greater recognition of damage and healing processes that promote transient fluid flow and rapid changes in effective stress that may trigger earthquakes and aftershocks.
Separately, we are also utilizing the poroelastic effects of fault slip to identify signatures of large scale slow slip behavior hidden within borehole pore pressure or water level measurements. Recurring large-scale slow earthquake slip along subduction zone thrusts is a relatively new discovery within the past 15 – 20 years and is now recognized as another important, yet somewhat silent, transient stressor to fault zones. The detection of large-scale (~M6+) slow slip earthquakes has largely depended upon continuous GPS measurements. The ability to detect subduction zone slow slip in hydrogeologic data provides the opportunity to improve both spatial and temporal constraints on large-scale slow slip activity, possibly allow for real-time of slow slip independent of seismic and geodetic observations, and perhaps allow for the record of slow slip in regions back in time before abundant geodetic observations were widely available.
These endeavors aim towards a goal of informing time-dependent earthquake hazard assessments, yet the fundamental processes and analysis techniques are also relevant for reservoir characterization and subsurface energy applications.