Numerous magmatic events may have breached the surface to produce volcanic eruptions.

The most recent volcanic phase began about 4 mya, producing largely andesitic eruptions.

The eruption was followed by a period of much less violent, lava producing eruptions.

These areas are in the program because they have been active in the last 2,000 years and have the ability to produce explosive eruptions.

But if the ice inside Triton is warmer than the surface, the volcanoes can produce eruptions, scientists say.

Haleakala has produced numerous eruptions in the last 30,000 years, including in the last 500 years.

The summit produces occasional phreatic eruptions that can coat the ice with ash.

Can volcanoes produce large explosive eruptions and rivers of fluid lava at the same time?

At some point the subsurface magma will produce phreatic eruptions and lahars.

And in a crater 650 feet below that is the volcano, which produces frequent noisy eruptions.