Around 5:00 p.m. local time on April 22, scientists at the Southern Andean Volcano Observatory in Chile began picking up volcanic earthquakes at the Calbuco volcano. A disturbingly short 60 minutes later, the volcano was in full eruption, producing an impressive column of ash extending more than 49,000 feet into the sky. Ash primarily drifted north and northeast of the volcano, covering towns below in a layer of fine ash. Observatory scientists quickly called for an evacuation zone of 12.5 miles.
A second explosive eruption began at 1:00 p.m. local time on April 23 and lasted for at least six hours. During this time an average of 150 earthquakes were recorded per hour. This eruption also produced a similar-sized column of ash, which drifted north, northeast, and east of the volcano.
My colleague Dr. Jeff Johnson, who co-taught a Boise State University geophysics and volcanology course with me at Villarrica volcano just after a March 3 eruption, reported from Pucón, Chile, that the Calbuco ash cloud blocked sunlight and turned morning to night. As of 11 a.m., on April 23, Pucón, which is more than 130 miles north of Calbuco, was still covered in darkness.
People who live in this part of Chile are well-accustomed to volcanoes, yet it is still causing widespread concern.
As a physical volcanologist, I’ve studied how people who live near volcanoes can deal with the hazards and risks from sudden eruptions as we’re seeing now in Chile.
On Close Monitoring
It’s hard to miss the multiple, large, ominous volcanoes that can be seen at any point along the drive from Chile’s capital city Santiago to the south of the country. Many of the volcanoes are remote and in sparsely populated areas, but others are popular tourist destinations for skiing, trekking, horseback riding, and visiting hot springs.
Because of frequent volcanic activity in Chile, especially as of late, volcano observatory scientists closely monitor Chilean volcanoes.
If a volcano begins to show signs of unrest, such as an increase in shallow earthquakes or ground swelling, observatory scientists go on a 24/7 monitoring schedule. Such was the case prior to the March 3 eruption of Villarrica. However, sometimes, despite careful monitoring, a volcano erupts with no warning at all.
