MANILA, Philippines -- The Philippines' most active volcano ejected lava fragments, ash and smoke in a thunderous explosion Monday, sending thousands of villagers back to evacuation centers and prompting a warning that a violent eruption may be imminent.
The midday explosion sent superheated lava, molten rocks and steam 2 to 3 miles into the blue sky, and some cascaded down Mount Mayon's slopes and shrouded nearby villages in darkness, Renato Solidum of the Philippine Institute of Seismology and Volcanology and other officials said.
From the crater, the deadly debris billowed about 2 miles down on the southern flank of Mayon toward a no-entry danger zone. There were no immediate reports of deaths or injuries, officials said.
The institute said the volcano was "exhibiting increased seismic unrest, lava fountaining and summit explosions." Footage captured by the agency showed bright orange lava fountains shooting out of the volcano's summit Sunday night.
The explosion was the most powerful since the volcano started acting up more than a week ago.
Solidum described two possible scenarios during a news conference Monday: Either Mayon will continue to ooze out lava with small eruptions in between, like what happened in 2006 and 2009, or it's the early stages of a blast or pyroclastic flow -- a deadly combination of lava, pumice, ash and volcanic gas barreling down a volcanic slope and into residential areas.
Compounding the threat is what's called lahar, a potentially deadly mudflow of volcanic material that can happen even without a major explosion. Solidum said heavy rain could drive mud in the region and cause landslides near already swollen bodies of water.
Due to its relatively gentle eruption last week, thousands left emergency shelters and returned to their communities in Legazpi city outside the danger zone. But Monday's blast sent nearly 12,000 fleeing back to evacuation centers, raising the number of people in those shelters to more than 30,000, Office of Civil Defense regional director Claudio Yucot said.
Authorities on Monday raised the alert level to four on a scale of five, which means an explosive eruption is possible within hours or days. A danger zone around Mayon was expanded to 5 miles from the crater, which means thousands of villagers will have to leave their homes, officials said.
Airplanes were ordered to stay away from the crater and ash-laden winds, and several flights were canceled.
Volcanic ash fell in about a dozen towns in coconut-growing Albay province, where Mayon lies, and in nearby Camarines Sur province, with visibility being heavily obscured in a few towns because of the thick gray ash fall, Jukes Nunez, an Albay provincial disaster response officer, said by telephone.
"It was like night time at noon. There was zero visibility in some areas because the ash fall was so thick," Nunez said.
More than 30,000 ash masks and about 5,000 sacks of rice, along with medicine, water and other supplies, were being sent to evacuation centers, Yucot said.
Romina Marasigan, spokesman for the National Disaster Risk Reduction and Management Council, told reporters last week that officials have allotted about $100,000 worth of assistance, including food, for evacuees.
Mayon lies about 210 miles southeast of Manila. With its near-perfect cone shape, it is popular with climbers and tourists but has erupted 47 times in the last 500 years, sometimes violently.
The Philippines lies in the "Ring of Fire," a line of seismic faults surrounding the Pacific Ocean where earthquakes and volcanic activity are common.
Another volcano in the "Ring of Fire" -- Japan's snow-covered Mount Kusatsu-Shirane, less than 1,900 miles away -- also erupted early today and injured at least nine people, officials with the Japan Meteorological Agency said. One person was believed missing.
Most of the injured were on the slopes of the central Japan ski resort, and some were in a gondola where glass was broken, apparently by a flying rock, said Makoto Shinohara, an official in Kusatsu town. Five people had broken bones, but none of the injuries were life-threatening.
The Japanese military said six soldiers were buried by a nearby avalanche, but they were all rescued. The soldiers were among about 30 taking part in ski training.
Information for this article was contributed by Jim Gomez and staff members of The Associated Press; and by Kristine Phillips of The Washington Post.
A Section on 01/23/2018
Print Headline: Volcano blows, sends Filipinos back to shelters