May 2015 – PHILIPPINES – Hundreds of people fled their homes on the slopes of a rumbling Philippine volcano on Friday as authorities warned of rain-driven mudflows from an approaching typhoon that could bury them alive. Around 500 residents of farming villages around Bulusan volcano in Sorsogon province, many of them children and elderly women, boarded army trucks clutching sleeping mats and bags of clothes as Typhoon Noul (local name: Dodong) bore down on the area. Trucks sent by the local government of Irosin town in Sorsogon and by the army and police on Friday started fetching residents living within the 4-km danger zone of Mount Bulusan. “I have no choice but to evacuate. I may not be strong enough to outrun the mud flows,” 66-year-old housewife Dolores Guela told Agence France-Presse. Officials said she and her meningitis-stricken nine-year-old granddaughter would be among about 1,000 people taken to temporary shelters to wait out the wrath of Noul, which was forecast to bring heavy rains in the Bicol region from late Friday.
The typhoon was gusting at up to 185 kph (115 mph) and experts warned debris from two recent ash explosions could rumble down the slopes of the 1,559-meter (5,115-foot) volcano. The state weather bureau Philippine Atmospheric, Geophysical and Astronomical Services Administration has placed Sorsogon as well as 10 other areas under Storm Signal No. 1. State vulcanologists subsequently raised Alert level 1 — the lowest in a five-step warning system — on Bulusan. Minor ash explosions alone would not normally prompt an evacuation, but authorities ordered one nonetheless because of the threat of mud flows, or lahar, from the approaching storm. Despite the preventive evacuation, some residents chose to stay because they said they still had to take care of their livestock and secure their belongings and harvested crops before they could eventually evacuate.
Bulusan, on the southeastern tip of the main island of Luzon, is about 400 kilometers (249 miles) south of the capital, Manila. It is among the country’s 23 active volcanoes. Noul would be the fourth major storm or typhoon to hit the Philippines this year. The disaster-prone nation is lashed by an average of 20 each year, routinely killing hundreds of people. –Inter Askyon
Volcano overdue for large eruption: The province of Sorsogon is preparing for a major Bulusan Volcano eruption, a probability bolstered by the volcano’s eruption pattern in recent years, said its disaster risk management chief. Raden Dimaano, head of Sorsogon’s Provincial Disaster Risk Reduction and Management Office said Bulusan is “due for an eruption.” “If you look at the frequency of its previous phreatic explosions, they do not reach 3 years [without an eruption]. Now, it’s overdue so we are really preparing ourselves.” He explained that the last major eruption happened in 2011. Before that, there was one in 2009 and, previously, in 2007. “That span of time seems to be when it gets clogged and then it suddenly blows up,” he said in a mix of English and Filipino.
This was verified by Louie Velasco, Science Research Analyst for the Philippine Institute of Volcanology and Seismology (Phivolcs) based in Sorsogon City. “For the past few years, that’s what has been happening in Bulusan. There are small ash explosions or phreatic eruptions followed by a big one. That’s a possibility. In 2011, that happened,” he told Rappler. Phivolcs has described Bulusan as characterized by “sporadic phreatic eruptions” during its restive periods. Alert Level 1 was raised over it following two eruptions in one week. The two eruptions lasted only 3.5 minutes and 5 minutes. Bigger eruptions, like the one that occurred in 2007, lasted for 20 minutes, thus spewing more ash and affecting more towns.
Phreatic eruptions are steam-driven explosions that occur when water makes contact with hot rock inside the volcano, producing steam that escapes violently through the crater. This type of eruption comes without warning and is not easily detected. Thus, phreatic eruptions can occur even when no alert level is hoisted over the volcano. Sorsogon waits for the worst-case scenario as Typhoon Dodong approached, prompting weather officials to raise Public Storm Warning Signal No. 1 over the province. Expected rainfall from the storm prompted Sorsogon officials to preemptively evacuate residents of Cogon in Irosin town, threatened by lahar that can be driven down Bulusan’s slopes by the rain. –Rappler