Supervolcano

The supervolcano of Yellowstone hasn't erupted in ages, but telltale signs such as deformation of land and earthquakes showcase its activity.

It’s said that the Toba supervolcano spewed some 2,800 cubic kilometers of material.

A supervolcano is defined as a volcano that at one time erupted with a force of magnitude 8 on the Volcano Explosivity Index (VEI), which means it erupted more than 1,000 cubic kilometers of material.

Mosaic of Olympus Mons on Mars. The supervolcano is nearly 600 kilometers wide at the base and 25 kilometers high and is capped by a crater 65 kilometers in diameter. It is about five times larger than the most massive volcanic cone on earth, Mauna Loa in Hawaii.

The stone went dark, and instantly the supervolcano burst with an unthinkable blast. A miles-deep plug of dark and hot earth flew upward, followed by a tremendous expanding cloud. Swirling, dense substance spread and thickened [...]

Sytau is rabidly volcanic; a dozen "supervolcanoes" 50-120 kilometers wide are erupting across the planet. Sytau's carbon content and constant volcanism make natural diamonds plentiful, if extremely costly and dangerous to recover.