Pinatubo Volcano Philippines 1991
Second Largest Volcanic Eruption in the 20th Century
Jul 22, 2008 Maureen K. Fleury
Pinatubo Volcano is located on the island of Luzon in the Philippines and is part of a chain of volcanoes that lie on the western side of Luzon in the Zambales mountain range stretching from the Lingayen Gulf to Bataan. There are still 22 active volcanoes in the Zambales range and Pinatubo was hidden among the other surrounding mountains. It didn't ever get much attention because it was dormant up to 1991 and was not highly visible.
The gentle slopes of Pinatubo were forested. Approximately 30,000 people lived in villages on the flanks. The fertile volcanic soil and the frequent rainfall made this area perfect for farming.
Events Leading up to the 1991 Pinatubo Eruption
July 16, 1990: An earthquake with the magnitude of 7.8 hit Luzon with the epicenter located approximately 55 miles northeast of Pinatubo.
March 15, 1991: A series of earthquakes occurred on the northwest side of Pinatubo and the intensity of these earthquakes continued to increase.
April 2, 1991: Small eruptions of ash and sulfur dioxide started and the earthquakes continued. This volcanic activity continued to increase until the end of May and then the emission of sulfur dioxide drastically decreased. This meant the flow of magma was blocked and a build-up of pressure would result in a large explosion.
June 3, 1991: Eruptions of magma began while ash continued to spew. These eruptions started to increase in intensity.
June 8, 1991: An explosion-type earthquake occurred in the afternoon and this was the beginning of intense eruptions that produced large steam clouds, heavy ash and pyroclastic flows (hot gas and rock, also known as tephra, which quickly travels down from volcanoes).
June 9, 1991 to June 14, 1991: Eruptions continued along with earthquakes. The ash fallout was increased and was started to blanket surrounding towns and cities. The ash plume which also contained pyroclastic materials had reached heights of 15 miles above the Pinatubo’s vent. The flow of hot rock and other materials cascading down the slopes blocked and overflowed rivers and streams. The strong winds blew ash throughout the Philippines and it traveled as far as Cambodia, Vietnam and Malaysia.
June 15, 1991: Ash and volcanic materials continued to spew and two explosions in the morning sent pyroclastic flows traveling at fast speeds of 50 mph. Further eruptions continued and by this time, the ash plume was 30 miles high. At 10:30am, a violent eruption occurred and it was followed by five more eruptions of equal strength. On the same day, Typhoon Yunya hit Luzon just north of Pinatubo. This brought strong winds that blew the ash further and the ash, when mixed with rain, made it extremely heavy. This caused rooftops on buildings to collapse.
June 16, 1991: Only minor eruptions occurred and seismic activity subsided.
Aftermath of the 1991 Pinatubo Eruption
- There were over 700 deaths and 184 people injured and 23 people never found. Due to well-organized evacuation efforts, fewer lives were lost. More than 1 million people were evacuated.
- The majority of deaths were caused by collapsing buildings and the death toll would have lower if the typhoon had not struck.
- Many people who lived on the slopes of Pinatubo never returned because their land was ruined forever.
- The crater on Pinatubo has filled up with water and it is now a large lake. The lava dome formed an island within the lake.
- Pinatubo has become a tourist attraction and visitors to Luzon are able to take a guided tour to the crater.
Sources:
- Pinatubo Volcano, the Sleeping Giant Awakes: ABS-CBN Broadcasting Corporation
- 1991 Eruption of Mount Pinatubo: US Geological Survey
Related Articles on Volcanoes:
Unrest at Mount Mayon Volcano in the Philippines
Related Blog on Volcanoes:
Volcanic Destruction Not Always Caused By Lava
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Mount Pinatubo Early Eruption 1991
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Mount Pinatubo 1991 with Marella River Valley
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Ashfall from Pinatubo 1991
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Lahar Flows on Mount Pinatubo
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