When will Yellowstone erupt again?
We do not know. Future volcanic eruptions could occur within or near Yellowstone National Park for the simple reason that the area has a long volcanic history and because there is hot and molten rock, or magma, beneath the caldera now. USGS scientists monitor Yellowstone for signs of volcanic activity using seismographs (to detect earthquakes) and GPS (to detect ground motion).
There is no evidence that a catastrophic eruption at Yellowstone is imminent, and such events are unlikely to occur in the next few centuries. Scientists have also found no indication of an imminent smaller eruption of lava.
Yellowstone's 2-million-year history of volcanism, the copious amount of heat that still flows from the ground, the frequent earthquakes, and the repeated uplift and subsidence of the caldera floor also testify to the continuity of magmatic processes beneath Yellowstone and point to the possibility of future volcanism and future earthquake activity.
The Yellowstone Volcano Observatory website has information on Yellowstone history and hazards.
Old Faithful Geyser erupts on a clear winter day in Yellowstone National Park
Midway Geyser Basin at Sunset, Yellowstone National Park
Great Fountain Geyser erupting in Yellowstone National Park on a clear day.
eruption of Lone Star Geyser, Yellowstone National Park
Visitors watching an eruption of Old Faithful Geyser from the Old Faithful Inn's balcony.
Photograph of the Old Faithful Geyser erupting in Yellowstone Nationl Park. Old Faithful was named in 1870 during the Washburn-Langford-Doane Yellowstone expedition and was the first geyser in the Park to be named.