Worryingly for Yellowstone, Professor Mather points out that supervolcanoes seem to put out a greater proportion of their ejected material as pyroclastic flows. That means towns near the ...

Scientists calculate that the pillar of ash from the Yellowstone explosion rose some 100,000 feet, leaving a layer of debris across the West all the way to the Gulf of Mexico. Pyroclastic flows ...

Mount Spurr has been showing signs of an eruption since last year, but scientists think one is even more imminent.

YAMAGUCHI—An eruption of Mount Aso in Kumamoto Prefecture 90,000 years ago created a pyroclastic flow that traveled 170 kilometers north to the Sabagawa river here, the longest such distance ...