Puyehue Volcano Eruption, Andes, Chile

• 1960 eruption
On May 24, 1960, 38 hours after the main shock of the 1960 Valdivia earthquake, the largest earthquake recorded in history, Cordón Caulle began a rhyodacitic fissure eruption. The earthquake had struck the whole of Chile between Talca (30°S) and Chiloé (43°S) and had an estimated moment magnitude of 9.5. Being located between two sparsely populated and by then isolated Andean valleys the eruption had few eyewitnesses and received little attention by local media due to the huge damages and losses caused by the main earthquake. The eruption was fed by a 5.5 kilometres (3 mi) long and north west-west (N135°) trending fissure along which 21 individual vents have been found. These vents produced an output of about 0.25 cubic kilometres (202,678 acre·ft) DRE both in form of lava flows and tephra.
The eruption began in a sub-plinian style creating a column of volcanic gas, pyroclasts and ash about 8 km in height. The erupting N135° trending fissure had two craters of major activity emplaced at each end; the Gris Crater and El Azufral Crater. Volcanic vents of Cordón Caulle that were not in eruption produced visible steam emissions. After this explosive phase the eruption changed character to a more effusive one marked by rhyodacitic blocky and Aa type lava flows emitted from the vents along the N135° trending fissure. A third phase followed with the appearance of short north-north west (N165°) oriented vents transverse to the main fissure which also erupted rhyodacitic lava. The third phase ended temporarily with viscous lava obstructing the vents, but continued soon with explosive activity restricted to the Gris and El Azufral craters. The eruption came to an end on July 22.