In a previous post I described the volcanic region of Yellowstone National Park and its history of volcanic eruptions. The Yellowstone super volcano is the youngest of a series of volcanoes that have erupted over the past 17 million years. During the last two million years, ash from each of three eruptions covered nearly half of the United States. Yellowstone is called a super volcano because its eruptions fall in the maximum range for explosiveness and volume of material ejected.
New research from the University of Utah shows that the volcanic plume of molten rock under Yellowstone, which would feed future eruptions, is bigger than previously thought.
A study in 2009, using seismic waves from earthquakes in the area estimated that the volcanic plume showed that “molten rock dips downward from Yellowstone at an angle of 60 degrees and extends 150 miles west-northwest to a point at least 410 miles under the Montana-Idaho border.”
The new study, using electrical conductivity measurements “shows the conductive part of the plume dipping more gently, at an angle of perhaps 40 degrees to the west, and extending perhaps 400 miles from east to west. The geoelectric image can ‘see’ only 200 miles deep.”
“The lesser tilt of the geoelectric plume image raises the possibility that the seismically imaged plume, shaped somewhat like a tilted tornado, may be enveloped by a broader, underground sheath of partly molten rock and liquids,” say the researchers. Although the research says nothing about when another eruption could occur, it implies that there is a potential for a very large, super eruption.
This research will be published in Geophysical Research Letters in a few weeks. Meanwhile, you can see more details and images in the press release here.