Yellowstone - 27 of 26
Yellowstone FAQs - 26 Found
The magma chamber is believed to be about 40 by 80 kilometers across, similar in size to the overlying Yellowstone caldera. The top of the chamber is about 8 km deep and the bottom is around 16 km deep. However, the chamber is not completely filled with fluid magma. It contains a partial melt, meaning that only a portion of the rock is molten (about 10 to 30%); the rest of the material is solid but, of course, remains hot.
The method that scientists use to discern this information is similar to medical CT scans that bounce X-rays through the human body to make three-dimensional pictures of internal tissue. In an analogous manner, a method called seismic tomography uses hundreds of seismograms to measure the speed of seismic waves from earthquakes and small, intentional dynamite explosions--data that allow geophysicists to make 3-D pictures of structures within the Earth. Scientists compare these seismic velocities, and infer the composition from deviations of these from average, thermally undisturbed values.