Unrest at Mount Mayon Volcano in the Philippines

Volcanic Eruption Possible due to Increased Activity

Jul 12, 2009

1984 Eruption Mount Mayon, Philippines, C.G. Newhall, USGS

Philippine volcanologists have raised the alert level at Mount Mayon to moderate unrest due to minor quakes and a glow observed in the summit crater.

Mount Mayon is located in the Philippines on the eastern side of the island of Luzon. It is a symmetrical cone-shaped stratovolcano and considered the most active volcano in the Philippines. The cone was formed by lava and pyroclastic flows produced from past eruptions.

In a news release posted in the Philippine Star on July 10, 2009, the following announcement was made:

“The Philippine Institute of Volcanology and Seismology heightened Mayon's status from ‘low-level unrest’ to ‘moderate unrest’. This alert condition signifies a state of unrest, which could lead to ash explosions or eventually to hazardous magmatic eruption. Meanwhile, local government officials have mapped out evacuation plans. Mountain-climbing activities are also banned.”

Cause of Volcanic Activity at Mount Mayon

Mount Mayon is part of the Pacific Ring of Fire. The eastern side of Luzon sits on the Philippine Trench where the Philippine Sea Plate is slipping under the Asian Continental Plate. As the two plates collide, it forms weak points in the earth’s crust. Magma, which is molten rock beneath the earth’s surface, is forced up these weak areas and is released. Mount Mayon was formed from the release of magma and is still serving as an active escape route.

Previous Eruptions at Mount Mayon

According to John Seach, a scientist and leading volcano adventurer, “Mayon Volcano has had a long history of destructive eruptions. The first recorded eruption occurred in 1616, and since that time about 40 eruptions have claimed more than 1500 lives.”

Some of the most notable eruptions of Mount Mayon are as follows:

August 2008: A mild ash explosion sent an ash plume above the summit. There was mild earthquake activity and a glow visible from the crater. There were no deaths and destruction of property.
November 2006: Typhoon Durian struck the Philippines and caused mudslides on the slope of Mount Mayon. Approximately 1,200 people were killed when the mud overtook the village of Padang.
February 2000: A series of eruptions spread a heavy blanket of ash in the area and mudflows posed a threat to the blocking of rivers. Thousands of villagers were evacuated.
February 1993: Pyroclastic flows from Mount Mayon killed 77 people in the farmlands at the foot of the mountain.
September 1984: An eruption of Mount Mayon produced lava and pyroclastic flows on the northwest side of the mountain. It also sent out an ash plume. There were no deaths but all vegetation was destroyed in the path of the flow.
June 1981: Typhoon Daling caused destructive mudflows and left 40 people dead and approximately 20 people injured or missing.
May 1978: An eruption sent lava down the southwest slope and there were high emissions of ash. There were 8,000 evacuated but no deaths.
April 1968: A series of 100 explosions in less than a month killed six people. There was extensive damage from ash emission and lava flow to areas within a 60-mile radius of Mount Mayon.
June 1897: The longest eruption lasted seven days and lava buried the village of Bacacay. Other villages were destroyed by falling hot rocks and blasts of steam. Over 400 people lost their lives.
February 1814: The most deadly volcanic explosion killed over 1,200 people in the town of Cagsawa. The stream of lava and cloud of ash buried the town and all that remained was the church tower. The survivors relocated to Daraga.

Residents who live around the slopes of Mount Mayon are currently banned from entering the three-mile permanent danger zone and a four-mile extended danger zone. They are also preparing for evacuation if the Philippine Institute of Volcanology and Seismology (Phivolcs) raises the alert status to Level 3. The current status of Mount Mayon is Level 2, which means a state of unrest.