VP and VS Structure of the Yellowstone Hot Spot from Teleseismic Tomography
Author | : Gregory Phillip Waite |
Publisher | : |
Total Pages | : 21 |
Release | : 2006 |
ISBN-10 | : OCLC:1305901944 |
ISBN-13 | : |
Rating | : 4/5 ( Downloads) |
Download or read book VP and VS Structure of the Yellowstone Hot Spot from Teleseismic Tomography written by Gregory Phillip Waite and published by . This book was released on 2006 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: [1] 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 because of the lack of adequate data. We employ new teleseismic P and S wave traveltime data to develop tomographic images of the Yellowstone hot spot 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 data set. The VP and VS models reveal a strong low-velocity 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 30° from vertical, west-northwest to a location beneath the northern Rocky Mountains. 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. A high-velocity anomaly, 1.2% VP and 1.9% VS, is located at ~100 to 250 km depth southeast of Yellowstone and may represent a downwelling of colder, denser mantle material.