Mushy magma beneath Yellowstone
Chu R, Helmberger DV, Sun D, Jackson JM, Zhu L. 2010. Mushy magma beneath Yellowstone. Geophysical Research Letters. 37
A recent prospective on the Yellowstone Calderadiscounts its explosive potential based on inferencesfrom tomographic studies which suggests a high degree ofcrystallization of the underlying magma body. In thisstudy, we show that many of the first teleseismic P-wavearrivals observed at seismic stations on the edge of thecaldera did not travel through the magma body but havetaken longer but faster paths around the edge. Afterapplying a number of waveform modeling tools, we obtainmuch lower seismic velocities than previous studies,2.3 km/sec (Vp) and 1.1 km/sec (Vs).We estimate the physicalstate of the magma body by assuming a fluid-saturated porousmaterial consisting of granite and a mixture of rhyolite meltand water and CO2 at a temperature of 800C and pressure at5 km (0.1 GPa).We found that this relatively shallow magmabody has a volume of over 4,300 km3 and is about 32% meltsaturated with about 8% water plus CO2 by volume.
- Type
- Journal Article
- Authors
- Chu, Risheng; Helmberger, Don; Sun, Daoyuan; Jackson, Jennifer; Zhu, Lupei
- Units
- GRYN
- Keywords
- rhyolite, Yellowstone Caldera