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Research Abstracts Online
January - December 2011

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University of Minnesota Twin Cities
College of Science and Engineering
Department of Earth Sciences

PI: Justin Revenaugh

Velocity Variations Around the 660 by Triplication Waveform Modeling

The seismic structure around the base of the upper mantle is crucial for understanding the thermal state and chemical composition of the mantle. Triplication waveform modeling appears to be an effective tool to unravel the detailed seismic structure of the mantle transition zone. However, most waveforms were calculated based on a one-dimensional layer model. This study uses three-dimensional synthetics to investigate the influence of subducting slabs and plausible low-velocity anomalies beneath the slabs to triplication waveforms. Benefiting from the recent deployment of dense broadband seismic arrays in the northeast Asia, observed P and S are available for constraining seismic velocities around the base of the upper mantle. Moreover, three-dimensional synthetics might correct some long-term biased models obtained by one-dimensional triplication modeling. Finally, in tomographic images, low-velocity anomalies have been observed beneath the descending high-velocity slabs in a number of subduction zones. Triplication waveform modeling by three-dimensional synthetics may be able to illustrate low-velocity anomalies and unravel their geometry. This will shed light on the mechanism for the anomalies.

Group Member

Tao Wang, Graduate Student