More violent: Indonesia’s Sinabung Volcano erupts 77 times in 24 hours

January 6, 2014 – INDONESIA – A volcano on Indonesia’s Sumatra Island erupted at least 77 times over the weekend, sending clouds of potentially deadly superheated gas barreling down the mountain and forcing the evacuation of more villages in the highly populated area. Mount Sinabung has displaced nearly 20,000 people from their homes since sporadic eruptions began in September. Experts have placed it under the highest alert status among the 127 active volcanoes in Indonesia, which is home to more active volcanoes than any other country and has some of the world’s most lethal volcanic activity. More people were evacuated Friday from villages in the path of hot clouds of ash and gases that on Saturday blew more than five kilometers (three miles) down the mountainside, said Sutopo Purwo Nugroho, spokesman for the national disaster-mitigation agency. ount Sinabung spews lava as seen from the village of Suka Ndebi in Karo, North Sumatra, Indonesia, on Sunday. That was the farthest such clouds,—also called pyroclastic flows,—had traveled to date. Experts say the flows, which move at high speeds and scorch everything in their path, are among the most dangerous volcanic events. When another of Indonesia’s volcanoes, Mount Merapi, erupted in 2010, almost 2,000 kilometers to the southeast on the archipelago country’s main island of Java—dozens of people were killed by superheated gases that tore into their villages far below the summit. The disaster agency said Sunday that Sinabung had erupted 77 times in the previous 24 hours, sending fine particles of ash up to 4,000 meters into the air. That marks a major increase in the frequency of eruptions, although the maximum height of the plumes has fallen to roughly half the peak level last week. Winds have been pushing the ash to the east and southeast, away from Indonesia’s third-largest city, Medan, home to more than two million people. 

Sinabung is an imposing massif rising to nearly 2,500 meters above the surrounding countryside, much of which is farmland in a district home to hundreds of thousands of people. It lies about 50 kilometers to the southwest of Medan, the provincial capital of North Sumatra, and 13 kilometers northwest of the district seat of Kabanjahe. The district numbers some 350,000 people. Mr. Nugroho, the disaster agency spokesman, said the evacuation zone, which has stood at a five-kilometer radius around the volcano’s peak, has been extended to seven kilometers in the southeast, where volcanic activity is greatest. Residents of more than two dozen villages have been living in temporary shelters outside that zone, some for months. Many of their homes are caked with ash and their small farms left unattended. If the no-go zone were the increase to 10 kilometers, the number of displaced persons would reach nearly 60,000, Mr. Nugroho said. The disaster agency cannot predict the mountain’s activity but has extended a period of extra caution to Jan. 18, he said. Mr. Nugroho said that the volcano is continuing to produce magma, or molten rock pushed up from deep within the earth, which is also the swelling the size of a lava dome near the peak.  

Partial collapses of the dome last week coincided with a series of lava flows down the mountain. In 2010, Sinabung came to life after lying largely dormant for hundreds of years, forcing the evacuation of around 12,000 villagers. Government scientists lack a deep understanding of the volcano’s characteristics, given its lengthy period of inactivity before then. Sinabung’s activity so far hasn’t risen to the level of Merapi, where pyroclastic flows extended for more than 15 kilometers at the height of activity in 2010. The evacuation zone extended to a radius of 20 kilometers around the peak. Those eruptions, over a series of months, killed more than 300 people and displaced hundreds of thousands. Mr. Nugroho cautioned that eruptions on Sinabung could occur even after the release of lava flows, as they did in the case of Merapi. Indonesia sits on the fault lines of the Pacific Ring of Fire, which experiences frequent earthquakes and volcanic activity. The Mount Toba super-eruption around 74,000 years ago in Sumatra created what is today the world’s largest volcanic lake. The eruption in 1883 of Mount Krakatau, which lies west of Java in the Sunda Strait separating the island from Sumatra, triggered a tsunami that killed tens of thousands of people, with the ash from the eruption lowering global temperatures for months. –WSJ