Dr. Scott Burdick joined the lab in October, 2015, as an NSF Postdoctoral Fellow. Over the course of the past three years, we have benefitted from his creativity, insight, and comradery. Now, we wish Scott the best of luck as he begins the next chapter of his life as an Assistant Professor at Wayne State […]
Congratulations and Farewell to Prof. Scott Burdick Read More »
Three undergraduate researchers from our lab – Erin Cunningham, Jesse Kolb, and Alex Kandell – presented their research findings at the American Geophysical Union Fall Meeting in San Francisco.
American Geophysical Union Read More »
At the broadest level, I seek to understand the state, dynamics, and dominant processes of the solid Earth, as well as those of other planets and satellites. Accurate seismic imaging is a crucial first step toward this goal. I believe that we stand at a threshold of a transformation in seismology, one enabled by the
Conversions of teleseismic shear (S) waves to compressional (P) waves across velocity interfaces (such as the Moho or the lithosphere-asthenosphere boundary) allow us to map out variations in plate thickness across Southern California. Anomalously thin lithosphere is observed beneath rifted regions, such as the Salton Trough. The stretching and break-up of lithosphere through a process
Lithospheric thinning beneath rifted regions of Southern California Read More »
When cluster analysis is used to classify the profiles of shear velocity (Vs) into N groups whose members are similar, the geographic extents of these groups mirrors the surface expression of tectonics. When N = 2 (panel a), one cluster corresponds to oceanic regions and the other to continental ones. As N increases, ocean basins
Cluster analysis of upper mantle tomography Read More »
Map of lateral variations in the velocity of seismic shear waves (S-waves) at a depth of 125 km. Warm colors denote slower wavespeeds, and are thought to indicate warmer temperatures and/or the presence of melt or water. Cool colors denote faster wavespeeds, and indicate cool regions, such as the mantle beneath the ancient, stable portions
Full waveform tomography with the spectral element method Read More »
Preferred model (solid line) of frequency dependence of attenuation within the absorption band compared with constraints from laboratory studies (hachured region) and the frequency-independent assumption (dashed line). In our model, α is approximately 0.3 at periods shorter than 200 s, decreasing to 0.1 in the period range 300–800 s, and becoming negative (−0.4) at periods longer than
Frequency dependence of seismic attenuation Read More »
Isotropic shear wavespeed variations in the upper mantle from the SEMum model [Lekic and Romanowicz, 2008]. The model is developed using the spectral element method to perform full waveform modeling. Note the structural complexity in the uppermost 100-200 km which must be corrected for in order to ensure robust scattered wave imaging. The slow velocity
Lithospheric structure beneath continental rifts Read More »
