The U.S. has over 160 active volcanoes. How likely are they to erupt like Kilauea in Hawaii?
But inside, these sleeping giants are volcanoes that could, in theory, blow at any time — though early-warning systems would likely prevent casualties.
There are more than 160 active volcanoes in the United States, according to the U.S. Geological Survey (USGS). Whether any will erupt soon, like Kilauea did in Hawaii on Thursday, is hard to tell until a few days or weeks in advance.
"It's really difficult to predict, because those volcanoes are relatively quiet until they start to activate an eruption," said Ben Edwards, a volcanologist and professor of earth sciences at Dickinson College in Pennsylvania.