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Michael Witek

PhD Candidate

B.S. Physics, University of Illinois at Urbana-Champaign, 2010
Curriculum Vitae

Research

I focus primarily on researching methods in seismic tomography. In particular, I am interested in ways to extract information from the Earth's ambient seismic wavefield in order to infer properties of the Earth's interior structure. Large earthquake signals provide a wealth of information about the structures that they pass through. However, heterogeneities in the Earth cause waves to scatter, and long after the main earthquake waves have passed, multiply scattered energy in the form of coda waves can still be recorded at seismic stations. As well, interactions between the Earth, the oceans, and the atmosphere also cause seismic waves to propagate and reverberate throughout the interior of the Earth. For most of the history of seismology, these signals have been ignored due to their small amplitudes and difficulties owing to seismic instrumentation of the time. Theoretical breakthroughs made in the past decade as well as the advent of large scale broadband seismometer arrays have now made the analysis of the ambient seismic wavefield feasible. By analyzing the continuous waveform data using a mathematical tool known as cross-correlation, we can estimate the so-called Green's function and extract signals caused by coherent energy propagating between a pair of seismic stations. Although my own research has mainly focused on the surface waves, it has been shown that body wave signals penetrating far into the deep Earth can also be observed. After processing the waveform data, traditional earthquake-based tomographic methods can be readily applied to signals extracted from ambient noise to produce models of the Earth.


Academic Awards

AGU Outstanding Student Paper Award, 2013

Funding Awards

Fulbright U.S. Student Award, 2014
NSF East Asia and Pacific Summer Institutes Fellowship, 2012

Selected Publications

Witek, M., S. van der Lee, and T.-S. Kang (2014), Rayleigh wave group velocity distributions for East Asia using ambient seismic noise, Geophys. Res. Lett., 41, 8045-8052, doi:10.1002/2014GL062016

Teaching Assistantships

EARTH 350: Physics of the Earth, 2012
Phys 101: College Physics: Mechanics and Heat, University of Illinois at Urbana-Champaign, 2010

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