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Vp and Vs structure of the Yellowstone hot spot from teleseismic
tomography: Evidence for an upper-mantle plume
Gregory P. Waite, Robert B. Smith Download a reprint: WaiteSmithAllenJGR2006.pdf (4Mb)
Abstract.
The movement of the lithosphere over a stationary mantle magmatic source, often thought to be a
mantle plume, explains key features of the 16 Ma Yellowstone-Snake River Plain volcanic system.
However the seismic signature of a Yellowstone plume has remained elusive due to the lack of adequate
data. We employ new teleseismic P and S wave traveltime data to develop tomographic images of the
Yellowstone hotspot upper mantle. The teleseismic data were recorded with two temporary seismograph
arrays deployed in a 500 km by 600 km area centered on Yellowstone. Additional data from nearby
regional seismic networks were incorporated into the dataset. The VP and VS models reveal a strong lowvelocity
anomaly from ~50 to 200 km directly beneath the Yellowstone caldera and eastern Snake River
Plain, as has been imaged in previous studies. Peak anomalies are –2.3% for VP and –5.5% for VS. A
weaker, anomaly with a velocity perturbation of up to –1.0% VP and –2.5% VS continues to at least 400
km depth. This anomaly dips 30º from vertical, west-northwest to a location beneath the northern Rocky
Mountains. Synthetic and resolution tests confirm this deeper low-velocity anomaly. In addition, a highvelocity
anomaly, 1.2% VP and 1.9% VS, is located at ~100 to 250 km depth southeast of Yellowstone.
We interpret the low-velocity body as a plume of upwelling hot, and possibly wet rock, from the mantle
transition zone that promotes small-scale convection in the upper ~200 km of the mantle and long-lived
volcanism.
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