IN The National Geographic Magazine for February of the present year there appears a very interesting account of the eruption of Katmai, in Alaska, which commenced on June 6, 1912. The Katmai ...

The Yellowstone caldera has a magma chamber about 40 by 80 kilometers across. The place where the stored melted rock meets solid, non-melted rock and forms a lid is called the magma cap.

The researchers also determined that the portion of the uppermost magma chamber is comprised of "about a 50/50 mixture" of volatile gases and liquids. "What this tells us is that the Yellowstone ...