About

I am a Post-Doctoral researcher at USC working primarily with Meghan Miller through an NSF-EAR postdoctoral fellowship. We are partnering with Fiona Darbyshire to explore the cratonic structure of the Hudson Bay region. In addition, we’ve conceptualized an improved method of regional imaging which we will apply across the USArray.

Contact info: rwporritt at gmail.com, rporritt at usc.edu, rob at seismo.berkeley.edu

New Paper! Porritt, Allen, and Pollitz, 2013 EPSL: Seismic imaging east of the Rocky Mountains with USArray.

I have recently completed a PhD in seismology at UC Berkeley. I worked with Richard Allen to constrain the seismic wave-speed structure with regional imaging methods. I am most interested in innovative methods of visualizing large datasets to find otherwise hidden information which may be key to solving the tectonic puzzle.

Scenes from UC Berkeley - Memorial Glade

Scenes from UC Berkeley – Memorial Glade (Photo credit: John-Morgan)

I recently developed the DNA13 tomographic model family. This model utilizes body wave delay times, teleseismic surface waves, and ambient seismic noise to provide constraints from the surface through the mantle transition zone. Additionally, we rotate waveform the data into the P-SV-SH ray oriented coordinate frame to measure two independent S wave arrivals. This allows an improved joint inversion of Rayleigh waves with SV component delay times.

I am also working with researchers at Los Alamos National Lab on an innovative method of model validation. We start with the proposition that a valid seismic model will be able to replicate waveforms to a degree of precision consistent with the model data fit. By simplifying the waveform metrics, we can can determine the improvement of fit through the use of finite frequency kernels over simple ray theoretical inversion kernels.

My first published work used Ambient Seismic Noise to image the lithosphere in Cascadia. [PDF] This study stemmed from two Flexible Array deployments I helped install, maintain, and eventually decommission in Cascadia. The FACES (FlexArray along Cascadia Experiment for Segmentation) and FAME (Flexible Array Mendocino Experiment) combined for approximately 100 broadband seismic stations. Utilizing these arrays we also looked at shear-wave splitting, ambient noise source location, body-wave tomography, and joint inversion of ambient noise, teleseismic surface waves, and reciever functions.

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