Research

Research Interests

  • Earthquake physics, focus on subduction zones and intraplate faults
  • Induced seismicity
  • Earthquake tomography, location and waveform cross-correlation techniques
  • Seismogenic zone processes and fault complexity
  • Volcano seismology

Most large (Mw > 7.0) and great (Mw>8.0) underthrusting earthquakes nucleate along a shallow region of unstable frictional stability on or near the subducting plate interface termed the seismogenic zone.  Traditionally, the seismogenic zone has been defined as the partially or fully coupled portion of the plate interface capable of generating large or great earthquakes, bordered updip and downdip by largely aseismic zones where brittle failure cannot initiate but may propagate (e.g., Scholtz, 1998; Hyndman et al., 1997). In the absence of one or more full seismic cycles along a subduction zone, characterizing the seismic hazard of a region has been done using proxies (i.e., temperature isotherms, extent of geodetic locking, location of background seismicity, prior damage extent). The concept of velocity-dependent material properties, the increasing recognition of slow and  aseismic slip within subduction zones, and the occurrence of tsunami earthquakes suggest that a complex interaction of processes controls the rupture limits of large and great earthquakes. High-precision earthquake relocations and 3D velocity modeling can lend insight into how thermal, mechanical, compositional, hydrological, and rupture processes interact within the subduction zone. Such studies allow comparisons between seismicity patterns and velocity perturbations that identify heterogeneities along the subduction megathrust that potentially influence the rupture patterns of the great earthquake sequences. Increased precision earthquake catalogs constrain subduction zone geometry, providing necessary input parameters for modeling main shock rupture, calculating moment, or modeling source characteristics of both the main shock and aftershocks.  Comparisons of aftershock locations to prior regional seismicity using high resolution hypocenters provide insight into seismogenic activity leading up to the main shocks.

My primary research topics encompass many aspects of seismotectonics and allow me to combine my broader interests in large-scale plate tectonics problems with seismology.  I am particularly interested in understanding the process of lithospheric recycling and earthquake generation within subduction zones, the role of fluids and fluid pressure in seismic wave generation, and the driving mechanisms leading to variability in characteristic seismic behavior along fault zones. The majority of my research to date utilizes earthquake relocation, local earthquake tomography, and waveform cross-correlation techniques. However, I do not consider my research to be limited to a particular set of tools, and I strive to expand my skills to incorporate other geophysical datasets.  I have recently been working with broadband waveform modeling, Empirical Green’s Function deconvolution, and Coulomb stress transfer modeling to study individual large magnitude earthquakes.