Magma accumulation at depths of prior rhyolite storage beneath Yellowstone Caldera

Seismic tomography has provided key insight into Yellowstone's crustal magmatic system that includes attempts to understand the melt distribution in the subsurface and the current stage of the volcano's life cycle. We present new tomographic images of the shear wave speed of the Yellowstone magmatic system based on full waveform inversion of ambient noise correlations, which illuminates shear wave speed reductions of greater than 30% associated with Yellowstone's silicic magma reservoir. The slowest seismic wave speeds (shear wave speed less than 2.3 kilometers per second) are present at depths between 3 and 8 kilometers, overlapping with petrological estimates of the assembly depth of erupted rhyolite bodies. Assuming that Yellowstone's magmatic system is a crystal mush with broadly distributed melt, we estimate a partial melt fraction of 16 to 20%.

Automated summary

Seismic tomography has provided valuable insights into Yellowstone's crustal magmatic system, particularly in understanding the distribution of melt in the subsurface and the current stage of the volcano's life cycle. By analyzing shear wave speed data, new tomographic images reveal a significant reduction in shear wave speed associated with Yellowstone's silicic magma reservoir. The slowest seismic wave speeds are found at depths overlapping with petrological estimates, suggesting a partial melt fraction of 16 to 20% in Yellowstone's crystal mush magmatic system.