Tomography from 26years of seismicity revealing that the spatial extent of the Yellowstone crustal magma reservoir extends well beyond the Yellowstone caldera

Abstract

The Yellowstone volcanic field has experienced three of Earth's most explosive volcanic eruptions in the last 2.1Ma. The most recent eruption occurred 0.64Ma forming the 60km long Yellowstone caldera. We have compiled earthquake data from the Yellowstone Seismic Network from 1984 to 2011 and tomographically imaged the three-dimensional P wave velocity (Vp) structure of the Yellowstone volcanic system. The resulting model reveals a large, low Vp body, interpreted to be the crustal magma reservoir that has fueled Yellowstone's youthful volcanism. Our imaged magma body is 90km long, 5-17km deep, and 2.5 times larger than previously imaged. The magma body extends ~15km NE of the caldera and correlates with the location of the largest negative gravity anomaly, a -80mGal gravity low. This new seismic image provides important constraints on the dynamics of the Yellowstone magma system and its potential for future volcanic eruptions and earthquakes. Key Points The Yellowstone magma reservoir is 2.5 times larger than previously thought The magma reservoir extends ~15 km NE of the 0.64 Ma caldera boundary These results show possible evidence for the NE migration of the hot spot © 2014. American Geophysical Union. All Rights Reserved.