Lobby > Exhibits > Scientific Research > What Lies Beneath > A CAT Scan of Earth

The tomographic data show that the magma body is perhaps 10 to 20 percent melt in a solid rock matrix—similar to a sponge with water in the porous spaces. It extends the length of the Yellowstone caldera and there appear to be two “fingers” of partially molten rock aimed at the ground’s surface. One is near the northeast side of the caldera, the second is in the vicinity of Old Faithful.

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