I am a fourth year graduate student at the Lamont-Doherty Earth Observatory at Columbia University in the Rock Mechanics Lab. My research revolves around trying to understand the mechanics of earthquakes using different methods.
Preparing an experiment on SHIVA on a visit to INGV in Rome (photo credit: Phil Skemer)
Fault Heating in the Japan Trench
The first half of my thesis focuses on the shallow portion of the seismogenic zone at the Japan Trench where the 2011 Mw9.1 Tohoku-Oki earthquake slipped to the surface and caused a large tsunami, leading to the disaster at the Fukushima nuclear power plant. A year after the earthquake, an ocean drilling expedition sampled the fault zone that slipped during the Tohoku-Oki earthquake. I have used trace element geochemistry to develop a detailed stratigraphy of the plate boundary fault zone, which gives insight into the distribution of deformation in this region. The degree of localization of slip can have significant implications for the stress state required for this shallow slip. I am also developing a biomarker thermal maturity indicator (using alkenones and n-alkanes) to determine whether faults in the décollement region have experienced a significant temperature rise (inferred to be the result of frictional heating). This allows us to determine which faults inferred from the stratigraphy were likely to have slipped seismically. Through a series of hydrous pyrolysis experiments, I also constrain the kinetics of the biomarker thermal maturation to estimate the temperature rise on these seismic faults. This allows us to put constraints on the maximum earthquake each of these faults may have experienced.
Sample prep to measure the organic content of sediments from the Japan Trench.
Friction of Carbonates
I am investigating the frictional behavior of subducting sediments with varying amounts of carbonate, a significant input to the sedimentary budget of subduction zones. Carbonate material tends to begin deforming plastically at shallower conditions (lower pressure and temperature) than silicate rock. However, carbonate-rich sediment has been observed to demonstrate unstable slip behavior over a wider range of conditions than more clay-rich sediment. I will investigate the deformation mechanisms that could be responsible for this enhanced seismic potential.
Carbonate faults in the field on a trip to the Apennines.