MANILA, December 23, 2009 (AFP) - The impending eruption of the Philippines' most active volcano, Mount Mayon, is the latest in a series of hazardous volcanic events that have rocked the country.

The Philippines is part of the so-called Pacific "Ring of Fire" that is known for its volcanic activity. Twenty-two active volcanoes are scattered around the archipelago.

Here are some key facts about Mayon volcano:

• Located about 330 kilometres (200 miles) southeast of Manila in the agricultural province of Albay, the 2,460-metre (8,070-feet) Mayon is listed by the Philippine Institute of Volcanology and Seismology as the country's most active volcano, having erupted 48 times in recorded history, claiming thousands of lives.

• Its deadliest eruption was in 1814 when more than 1,200 people were killed as lava buried the town of Cagsawa. The town's church steeple is all that remains, and has become a national landmark and a tourist attraction.

• Its last eruption was in August 2006 where it oozed lava and emitted ash and smoke for months. No one was killed by the eruption itself but in December of that year a passing typhoon dislodged tonnes of volcanic ash from Mayon's slopes, turning it into fast-moving mudflow that covered villages and killed about a thousand people.

• The fertile volcanic soil of Mayon has attracted many farmers to work its slopes and foothills despite the government's imposition of a six-kilometre permanent danger zone around the volcano.

• Mayon's eruptive phases have lasted for months, forcing thousands of people who live in its foothills to stay for lengthy periods in government evacuation centres.

• Government volcanologists say that in its latest restive stage, Mayon will either continue emitting smoke and ash and oozing lava or explode suddenly, sending a huge column of ash into the sky.

• Thanks to its picture-perfect cone, Mayon is a major tourist attraction. Its eruptions bring even more tourists who watch lava pouring out of the volcano from the safety of a hill in Legazpi City.

Here are some key facts about volcanoes in the Philippines in general:

• The most powerful volcanic explosion in the 20th century occurred in June, 1991 when the supposedly dormant Mount Pinatubo, about 100 kilometres northwest of Manila, erupted, sending thousands of tonnes of volcanic ash into the air. The ash travelled around the globe, changing temperatures worldwide, scientists said.

• Volcanic ash from Pinatubo mixed with rain and created deadly volcanic mudflows that covered whole towns and forced the US military to evacuate nearby Clark Airbase. About a thousand people died from the effects of the eruption.

• Taal volcano, one of the smallest volcanoes in the world, is located just 50 kilometres southwest of Manila. The volcano sits on an island in a lake and has a sulphuric lake at its crater. It last erupted in 1977.