A gigantic bulge in the north rim of the Yellowstone caldera is the latest sign of volcanic activity in the national park.

Scientists are monitoring a city of Chicago-sized swath of rising ground at the northern volcanic rim of the Yellowstone ...

At Puʻuʻōʻō, fissures reopened on either side of the vent, while at Maunaulu, the eruption stalled and the vent collapsed ...

Episode 41 of lava fountaining to more than 1,600 feet high as part of the ongoing episodic summit eruption of Kīlauea ...

This stunning astronaut photo shows the natural beauty of Japan's Aso Caldera — a giant crater-like bowl containing 17 different volcanoes, leftover from major eruptions spanning over 200,000 years.

Learn more about the past eruptions at Yellowstone National Park and how each new eruption displaced evidence of the past.