Over three million visitors step onto this charged volcanic landscape every year. Yet the geologists that monitor it are unconcerned about a large, imminent eruption. Far more unnerving is an encounter with one of the park’s wolves or bears.
Basic math on Yellowstone's eruption cycle (one event every 600,000 to 800,000 years) seems to suggest a fourth event, well, about now. Heasler demurs. ”Three data points do not make a compelling argument for almost anything in science,” he says. Geologists are uncertain whether Yellowstone is winding down from the third eruption or ramping up to a fourth.
Technically, the next eruption could happen anytime. However, catastrophic eruptions occur so infrequently in the geologic record that it is statistically not likely anytime soon. More importantly, if Yellowstone were preparing to blow another big one, its heavily monitored signs of unrest would also clearly indicate imminent eruption. (They don’t.) http://sciencebulletins.amnh.org/earth/f/y...essays/83_1.php