April 22, 2015 Eruption of Calbuco

Most Recent Weekly Report: 22 April-28 April 2015

OVDAS-SERNAGEOMIN reported that an eruption from Calbuco began at 1804 on 22 April, prompting the Alert Level to be raised to Red (the highest level on a four-color scale) and causing a 20-km exclusion zone to be declared. The eruption was preceded by an hour-long period of volcano-tectonic events followed by long-period events; no increases in seismicity had been noted since 2009 when real-time seismic monitoring started. After a large seismic event detected at 1735, a 90 minute eruption generated a sub-Plinian, gray ash plume that rose 15 km above the main crater and drifted mainly ENE, although fine ash drifted N and NW. Column collapses occurred locally and radially, affecting the headwaters of major rivers. Residents within the exclusion zone, in Chamiza, Lago Chapo, and Correntoso sectors, and in the town of Puerto Montt, were ordered to evacuate. Several roads and bridges were impassable due to ashfall. A larger second event on 23 April began at 0100, lasted six hours, and also generated a sub-Plinian ash plume that rose higher than 15 km and drifted N, NE, and E. About 5,000 people had been evacuated and ONEMI warned people not to go within 200 m of drainages due to lahar hazards. News articles noted that international flights in and out of several major cities were delayed or canceled. Some houses in areas near the volcano collapsed from the weight of the ash. ONEMI noted on 27 April that 246 of 4,514 evacuees were in shelters; the number of displaced people had peaked at 6,514 during 24-26 April. (reference #11206)

Last week's spectacular twin eruptions of the Calbuco volcano will cost southern Chile's Los Lagos region, a tourism and agriculture hub, up to $600 million, a local business leader said Monday. The region is struggling to clean up some 210 million cubic meters (7.4 billion cubic feet) of ash spewed by the volcano, which contaminated rivers, lakes and vast stretches of prairie. "The Los Lagos regional economy had annual turnover of $2 billion. We estimate the eruption of Calbuco will cause losses of up to about 30 percent," he said. Los Lagos has more than a million head of cattle, around 30 percent of the total in Chile, and supplies about half the South American country's milk. Chile's salmon industry, the world's second-largest, is also facing losses. Los Lagos has the largest concentration of salmon farms in the country, but many had their water supplies contaminated by ash.The effect on the region's key tourism industry, which draws about 200,000 visitors a year, is less clear. "The volcano could decrease the number of tourists coming for outdoors activities... but it could also increase the number of tourists who want to see an active volcano," said Jadue. (reference #11205)