1600

Huaynaputina Eruption

When it comes to volcanoes, looks can be deceiving. Some of the largest and most destructive volcanoes in geologic history—so-called “supervolcanoes”—reveal themselves today not as tall, iconic volcanic mountains like Vesuvius or the volcanoes of the Cascades Range, but instead as inconspicuous, broad circular depressions. Such eroded craters are all that remain of past supervolcanoes near Yellowstone National Park or Crater Lake in Oregon, although these dormant geologic giants could once again waken in the future.

Truly colossal volcanic eruptions are rare. The most recent isolated extreme eruption anywhere on Earth was the 1991 eruption of Mt. Pinatubo. A larger concentration of geologically recent extreme eruptions has occurred within the Andes Mountains of South America, however, including the eruption of the Huaynaputina volcano in southern Peru in 1600.

Residents in cities near the volcano began reporting feeling earthquakes and seeing small steam eruptions come from the summit starting about four or five days before the actual eruption, which occurred on the morning of February 19. An enormous plume of ash and smoke (now called a Plinian plume, after the chronicler of the Vesuvius eruption’s plume in the year 79) jetted high into the stratosphere and influenced the global climate for decades. Soon after the eruption, ash began to blanket the surrounding terrain. The ash and pyroclastic rocks fell into nearby rivers, creating a rapidly flowing slurry of water, mud, and volcanic debris called lahars that laid waste to forests, fields, and towns along the riverbanks all the way to the ocean, some 75 miles (120 kilometers) away. Nearly a dozen villages were buried by ash, and an estimated 1500 people were killed during the initial eruption as well as subsequent intermittent eruptions over the next month.

The Huaynaputina eruption is just the most recent of five colossal volcanic eruptions that have occurred in the Andes over the last 700 years or so. Will there be others along that highly active collisional plate boundary? Absolutely. Can scientists provide adequate warnings about them to help save lives and property? Most likely, based on the eyewitness accounts of previous supervolcano eruptions there and elsewhere in the world. But that means continuing to be diligent, and to make volcano monitoring a priority.

The Huaynaputina volcanic crater in southern Peru, which represents the relatively inconspicuous remains of the largest historical volcanic eruption in South America.