Research:

Branch Faults

What is a Branch Fault?

Fault systems in nature can be quite complex. These complexities can affect how rupture may propagate along a particular system and may yield some insight into possible earthquake scenarios. My research focuses on branch fault systems where two faults intersect. I try to identify parameters that may influence how rupture propagates through branch fault intersections, which can have implications for regions such as Southern California, New Zealand, Turkey,etc. I conduct this research using FaultMod (Barall, 2009) a finite element code designed for dynamic rupture modeling.

Effects of Dip Angle

Although faults are often modeled as purely vertical many natural fault systems have non-vertical dipping components. In this research we highlight how non-vertical fault segments can promote through going rupture along branch fault systems. Interestingly we find that the dip-slip component on secondary faults induces free surface interactions which promotes rupture to propagate from the secondary fault to the main fault for surface rupturing faults. When we model the branch fault as a buried system, these free surface effects decrease and rupture remains solely on the secondary fault. (Review BSSA)

Effects of Topography

Many faults are in close proximity to mountian ranges or valleys, and it has been shown that this topography can introduce dynamic changes in normal stress during rupture. In this research we aim to understand how these dynamic normal stress changes could influence the ruputure path along branch fault systems . We find that the magnitude of these normal stress perturbations increases with slope steepness and can lead to through going ruputre onto the secondary segment.

Material Contrast

Fault systems can separate rock formations with different material properties. Here we investigate whether asymmetry in wave speeds across a branch fault system can influence the ruputre behavior. We find that material contrast can play a role in the self determination of rupture at the branch intersection.

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