YELLOWSTONE NATIONAL PARK — Yellowstone Volcano Observatory’s (YVO) latest Caldera Chronicles explores the unique way that images get created to reveal magma beneath Earth’s surface.
The most common method of tomography employs seismometers, machines that measure movement or shaking in the subsurface of the earth. Seismometers can generate data that reveals variations in the physical properties of the earth.
YVO points out that this technique works backwards, called “inversion.”
“Because we can’t directly take a measuring tape underground and inspect a magma reservoir, we have to rely on the fact that this magma reservoir can affect measurements of other things, like seismic waves that pass through,” YVO writes. “The inverse solution is to take the pattern of measured seismic waves and work backwards to find a plausible model of the conditions underground that would cause that pattern.”
According to YVO, a common method of seismic tomography involves measuring the travel time for seismic waves from earthquakes and noting where they arrive at seismometers “late.” This “lateness” shows regions of rock where seismic waves travel more quickly or more slowly, which can help scientists estimate physical properties like temperature, rock type, density or the presence and amount of magma.
There are alternative measuring techniques as well; lightning and solar storms can also map magma, in addition to showing future Yellowstone eruptions. Read more about that here.
