Pyroclastic flow cascades down volcano’s slope

The Manila Times - August 14, 2006

MAYON Volcano could soon unleash a huge cloud of deadly gases and ash, experts warned Sunday, as 40,000 people prepared for a second week in crowded evacuation centers.

Four powerful ash explosions rocked the spectacular 2,460-meter peak on Saturday, covering nearby communities to the northwest with a light layer of dust, government volcanologists said.

Mayon, where activity has picked up over the past week, is now belching a more lethal pyroclastic flow of hot volcanic gas and dust, rather than slow-moving lava, said Ed Laguerta, head of the volcano-monitoring observatory.

Unlike the trails of lava that have been slowly flowing down the volcano’s slopes for weeks, so-called pyroclastic flows can cover a wide area very swiftly, moving at speeds of about 60 kilometers (35 miles) per hour.

“We want to give the volcano a wide berth,” said Ernesto Corpuz, head of the volcano monitoring division of the Philippine Institute of Volcanology and Seismology.
An eruption at Mayon in 1993 killed 77 people who were caught unaware by the deadly clouds of ash and gases.

The government has evacuated some 40,000 residents living in a six-to-eight-kilometer danger zone around the volcano, herding them into 24 overcrowded evacuation centers, most of them schools.

Many residents, however, still enter the danger zone to work on their farms, guard their belongings and attend to other personal matters.

The full extent of the danger posed by the volcano is not readily apparent as its crater has largely been obscured by thick clouds for days, preventing the public from seeing the ash explosions.

President Arroyo, who visited Mayon on Saturday, has promised more aid for the villagers including the delivery of prefabricated homes and tents, in a bid to ease overcrowding at the evacuation centers.

Some have been forced to sleep in rooms with as many as 50 other people, raising fears about the possibility that disease could spread.

Despite the dangers of Mayon, busloads of evacuees could been seen leaving the center in Legazpi City on Sunday to visit their homes in Bonga village, inside the danger zone, where people said they could hear a distant rumbling.

Seventy-four-year-old farmer Maximo Aydalla said he was in Bonga on Saturday when the ash explosions took place.

“I saw the smoke rise and then fall but we were still at a safe distance. If it was going our way, we would have run,” he said.

Despite the danger, he returned to Bonga again on Sunday to pick up drinking water and firewood.

“It is a bit dangerous. I am not afraid because I keep an eye out,” he said.
There have been no recorded fatalities so far from either the volcano or from diseases at the evacuation center.

Relief officials said they were checking on television reports that one person had died of a heart attack.

Mayon is the country’s most active volcano and past eruptions have led to more than 1,000 deaths.

The pyroclastic flow was observed on Mayon’s upper slopes between Basud and Buyuan barangays in Legazpi. The flow was cascading down at 60 kilometers per hour with temperatures reaching 300 degrees Celsius.

An ash column rose about 500 meters high into the sky and drifted towards to the northeast, raining light ash over the town of Santo Domingo.

Cedric Daep, chief of the Albay’s Provincial Disaster Management Office, told The Times that in case of bad weather, the present eight-kilometer danger zone around Mayon will be extended by two kilometers and 10,000 more families will be forcibly evacuated.

That means the government will be spending P2 million a day or P14 million a week or P56 million a month to feed, clothe and treat all the evacuees.

At least 10 volcanic earthquakes and 324 tremor episodes have been recorded since Saturday, indicating that magma continues to rise to the crater.

The volcano, however, spewed 8423 tons of sulfur dioxide on Saturday, a decrease of more than half from the previous day’s volume.

“The explosions and significant drop in sulfur emission rate indicate a continuing high unrest in the volcano,” Laguerta said.
--AFP and Rhaydz Barcia