2 Million People Live Near ‘Mouth of Hell’ Volcano. It May Be Hiding a Second Magma Chamber

When Spanish conquistadors first laid eyes on the Masaya volcano’s lava lake in the early 1520s, some believed it must be the entrance to hell. Recent activity from Nicaragua’s busiest volcano has mostly consisted of passive degassing, lava lake formation, and vent-clearing blasts, but Masaya has also produced at least four massively explosive Vesuvian eruptions throughout its history.

That’s unusual for a basaltic shield volcano like Masaya. These volcanoes tend to produce slow, effusive lava flows, but Masaya can transition…