In January 2022, a giant undersea volcano explosion rocked Tonga in the Pacific. How do scientists find where and when the next one will blow? During the summer of 1883, a caldera in the Sunda Strait, ...

On a remote, uninhabited island far out in Alaska’s Aleutian chain, a volcano has been quietly building itself higher for years. Great Sitkin is not exploding, and it is not throwing ash into the sky.