Facts about Mount Pinatubo

Luzon Volcanic Arc is a chain of volcanoes across the Luzon Strait.

Mount Pinatubo’s history is divided into two stages—the ancestral Pinatubo and the modern Pinatubo.

The ancestral Pinatubo began about 1,1 million years ago and presented much less destructive activity than the Modern Pinatubo. However, the last eruption, considered at least five times larger than the eruption of 1991, gave birth to what is called the modern Pinatubo, some 35,000 years B.C.

They are:

• Inararo Eruptive Period (35,000 B.C.)
• Sacobia Eruptive Period (15,000 B.C.)
• Pasbul Eruptive Period (7,000 B.C.)
• Crow Valley Eruptive Period (4,000–3,000 B.C.)
• Maraunot Eruptive Period (1,900–300 B.C.)
• Buag Eruptive Period (A.D. 1,500)

Learn some facts about lava

There were many villages on the slope of the volcano, housing over 30,000 people.

It struck the island of Luzon, approximately 100 kilometers northeast of Mount Pinatubo, and claimed the lives of 1,621 people. The earthquake was followed by small rockslides and no pre-eruptive volcanic activity.

For the following two weeks, the seismic activity in the region has been continuously increasing, foreshadowing the catastrophe.

The news reached a volcano observatory in Manila, where seismographic equipment was set to monitor the increasing seismic activity of Mount Pinatubo. Within the next few weeks, several small eruptions scattered the volcanic ash in the surrounding areas. Daily earthquakes were counted in hundreds.

The difference between the emission from the beginning of May to the emission at the end of the month was tremendous—it has risen from 500 tn to 5,000 tn.

The first contained everything within a range of 10 kilometers from the summit, the second 10-20 kilometers, and the last one 20-40 kilometers. Evacuation of the first zone started on April 7th, the second on June 7th, and the last one on June 13th. The effort put into evacuating people from the blast area saved hundreds of thousands of lives and is considered one of the most successful hazard mitigation efforts.

It was rated a 6 on Volcanic Explosivity Index (VEI), making it the second largest eruption in the 20th century. The blast lowered Mount Pinatubo’s peak from 1,745 meters to 1,485 meters, creating a caldera 2,5 kilometers in diameter in its place. The eruption released over 22 million tn (short tons) of sulfur dioxide into the stratosphere. The column of ash and smoke was over 30 kilometers high. The climatic phase lasted for about 15 hours. Over 350 people perished during the eruption.

The combination was devastating. Large amounts of ash dusting from the volcano were moistened and caused flooding and massive lahars.

Over 200,000 people were left homeless, and over 30,000 people had to relocate. The eruption caused over US$700,000,000 in damage.

The global temperature dropped by 0,4 degrees Celsius in 1992 and 1993. The eruption produced a large number of aerosols, increasing chlorine’s strength at destroying ozone, and thus the ozone depletion noticed an increase.

People are eager to visit Lake Pinatubo, which formed at the summit of Mount Pinatubo after the climatic eruption of 1991.

Mt. Pinatubo crashed into Mount Manunggal, killing president Ramon Magsaysay along with 24 people aboard.