New study reveals insights into Yellowstone Volcanic System’s Hidden Magma Reservoirs

HILO, Hawaii - Researchers from the U.S. Geological Survey and Oregon State University examined the area beneath Yellowstone Volcanic system finding that although an eruption is unlikely anywhere in the area, changes to the northeast area of the volcanic system will be the key to understanding future eruptions.

Scientists at USGS mapped underground areas containing magma in this volcanic system. Understanding where magma is located is essential for predicting volcanic activity and keeping the public informed about potential risks. This study gave a clear picture of how magma is distributed through the crust at Yellowstone using a method that is most sensitive to the presence of magma and is an ideal tool for imaging volcanic systems. The method relies on the Earth's natural electromagnetic field. In Yellowstone, which is the largest volcanic system in the United States, this method of mapping magma has brought a new level of understanding to how the system may change in the future.

Scientists mapped rhyolitic magma, a form of magma or hot molten rock, that has caused previous explosive eruptions in Yellowstone. The study found that across Yellowstone Volcanic system, the percentage of this rhyolitic magma is low indicating an eruption anywhere is unlikely. An area in the northeast of Yellowstone Volcanic system though, does have the capability of producing more rhyolitic magma because of an underground heat source located there, known as crustal basalt.

"The area in the northeast has a direct connection to a crustal basaltic heat source beneath it which can fuel the generation of additional rhyolitic magma in that area. This could mean someday, though certainly not now, there could be enough rhyolitic magma to cause eruptive activity in the northeast" said Ninfa Bennington geophysicist with the USGS and lead author of the study. "We can assume from our research that while volcanic activity in the west part of Yellowstone could be waning, future activity may be focused in that northeast area. This knowledge will be crucial for assessing future volcanic hazards in the region."

Adam Schultz, a professor of geophysics at Oregon State University and collaborator on the project, said the findings reinforce that volcanoes are dynamic features and the magma sources that may exist underneath them evolve over time and migrate.

"What we are seeing really speaks to that migration and evolution of the bodies now that we can image them, particularly by making use of the power of the magnetotelluric method of imaging magma bodies," Schultz said. "That is information that can be used by people interested in modeling the dynamics of these systems, and that can contribute to efforts to make risk assessments."

USGS and its partners maintain networks of instrumentation to monitor activity at Yellowstone as part of the National Volcano Early Warning System. USGS is also committed to studies that further our understanding of the volcanic system and its hazards. Learn more in the article published in Nature and at the USGS's Yellowstone Volcanic Observatory website.