Mount Pinatubo located on the boundaries of Pampanga, Tarlac and Zambales, Philippines has erupted on the 15th of June 1991. With the arrival of Storm Yunya, the impacts of the eruption worsen as the lahar rushes down the lowlands. Villages near the foot of Pinatubo were buried. Forests and agri-lands were devastated. Americans destined in Clark Air Base left Philippines and never came back. Hundreds of Billions of Peso worth of buildings, houses, bridges and other infrastructures were damaged. Inspite the effort of the government and other volunteer groups, the death count was 737 which were caused directly by the eruption, lahar and diseases brought by the cramped evacuation centers. 195 were injured and 24 were reported missing. The eruption has global impact. It was thought to have ended the drought in San Francisco and have caused the flooding in China. It depleted the ozone layer. It caused what the scientist called regional nuclear winter.
Pinatubo is one of the many volcanoes found in the Philippines. It is located on the boundaries of Pampanga, Tarlac and Zambales. It was elevated at a height of 1.745 km and has base diameter of 40 km. No data of its past eruptions were recorded until June of 1991. The impact of Pinatubo’s eruption did not only affect the Filipinos and the natives living near the foot of the volcano but also the Americans destined in the Clark Air Base, a U.S. military base in the Philippines. The rest of the world as well was affected.
The impact of the eruption of Pinatubo has worsened when storm Yunya arrived. The devastation done by both the eruption and the storm was so severe that a total of 956 people were killed, injured and were reported missing. Thousands of families were left homeless. Hundreds of billions of Peso worth of properties were destroyed.
The effect of its eruption was experienced globally. I was believed to have caused some natural disasters such as the flooding in China. According to some scientists, the eruption contributed to what they call a regional nuclear winter. The gases that were emitted depleted the ozone layer.
The fury of Pinatubo started with a hydrothermal explosion on April 2, 1991. A heavy rumbling sound was heard as it emitted steam clouds and 500 to 800 m high ashes. Scientists and volcanologists from the Philippine Institute of Volcanology and Seismology (PHILVOLCS) monitored Pinatubo’s activities from their various monitoring stations. From April 6 to June 6, scientists recorded a maximum 178 high frequency volcanic quakes (HFVQ). On June 3, Pinatubo emitted ashes for 30 minutes. On June 8, 3:25 PM, an explosion type earthquake was recorded. June 9, 2:00 PM, the seven steaming vents emitted ashes. It was followed by an emission of thick ashclouds which glided west-northwest into Maraunot River. Two minutes later, ashclouds flowed west to Moraza River. According to the detailed records of PHILVOLCS, Pinatubo’s imminent eruption slowly accelerated with irreversible and critical velocity starting June 9. June 10, 1:30 PM – 4:30 PM, plump ashclouds were emitted. It reached a maximum height of 4000 m above the summit. Ashfalls flooded the areas within the 8 km to 10 km radius. Continuous tremors with maximum double amplitude of 6.0 mm were recorded. June 11, 5:00 AM, a 3000 m – 3500 m high steam clouds and ashes were emitted. Later of the day, it reached a maximum height of 5000 m. June 12, 3:00 AM, maximum double amplitude of 8.0 mm to 30.0 mm of quakes were recorded. At 8:51 AM, the emissions reached a maximum height of 20,000 m from the vent. Three hours later, minor explosions rose to 5000 m. Deposits of lahar began to flow 15 kms down to the major rivers. June 14, series of tumultuous eruptions were generated. By 1:09 PM, the emitted ashes reached 25,000 m high. It was followed by a 30,000 m high at 3:20 PM. At 7:21 PM, the mushroom-shaped emission tapered to 6,000 m but leaped again to 20,000 m at 10:21 PM. The surrounding towns were already covered with ashes. Pyroclastic flows were observed to an extent of 15 kms from the summit down to Maraunot River. June 15, 1:15 AM – 2:57 AM, Pinatubo unleashed its fury. In the dark it emitted an incandescent pyroclastic flow and disgorged a globular mushroom that towered as high as 15,000 m to 25,000 m and as wide as 15 kms to 18 kms. From 5:15 AM – 8:31 AM, the ejection of billowing ashes was sustained. Authorities pointed out for possible violent calderagenic eruption but on the 16th the possibility was reduced. But still, a high alert level 5 was sustained due to the increased danger brought about by lahar. In October, after the rainy season, what was once a furious volcano was already covered by green pond.
The immediate impact of Pinatubo eruption was widespread. Rocks were hurled 40 kms away as far as San Fernando, Pampanga. Sandfall reached Metro Manila which resulted to the closure of Ninoy Aquino International Airport for weeks. Ashfalls were recorded in Aklan, 500 kms south of Pinatubo, and in Palawan, 900 kms southwest. Ashes also drifted across the sea, to other neighboring Southeast Asian nations. (Avedaño, 1991, p. 1) “According to the satellite observations of the National Oceanic and Atmospheric Administration in Washington, two months after eruption, the volcanic debris towered as high as 14 miles (22.5 kms) and has engulfed 20 degrees North and South of the equator.” (as cited in Dacanay, 1991, p.26) It was roughly estimated that the ashes has spread and expanded north to Mexico and down south to Rio de Janero. It was believed that the eruption ended the drought in San Francisco. It was also believed that it caused the floods in Yangtze and Huaihe River Valleys in China, which killed almost 2000 Chinese.
The eruption affected most the Filipinos, especially in the nearby villages. It buried 18,000 hectares of land in the mountains of Botolan and San Marcelino, Zambales; Porac and Floridablanca, Pampanga; and Bamban, Tarlac. 43,801 hectares of century old natural forest and plantations were inundated. (Avedaño, 1991, p. 8)
The already devastated villages and people worsened when, while Pinatubo was at its peak of fury, storm Yunya arrived. Yunya has a scornful velocity of 100 kph and gustiness of 125 kph arrived. Lahar rushes to the villages. Eating up everything it encountered on its way. Trees, boulders, houses, buildings and other infrastructures were destroyed when a 32 kph lahar passed, killing the locals and their livestock. The lahar deposited tens of millions of cubic yards of mud on the lowlands in a single day. It buried houses, school buildings, churches, bridges and everything else. An estimated 0.7 cubic miles of debris were deposited on the surrounding lowlands.
19,799 hectares of the government reforestation project and P125 M ($4.62 M) worth of seedlings were destroyed by the lahar. 10,200 hectares of agro-forestry farms under the Integrated Social Forestry Program of the Department of Environment and Natural Resources were devastated. The Taug Dike in Angeles City, 16 kms away from the summit, was also destroyed. Rice fields were buried in Moraza, Bototan, Zambales. In all, an estimated 60,000 out of the 80,000 hectares of agri-land were destroyed in whole Central Luzon. The damage was estimated to cost P453.179 M ($16.78 M).
An estimated 695,000 heads of cattle were decimated due to contaminated water, lack of feeds and loss of grazing fields. About the same number applied to the poultry and livestock. (Basa, 1991, p. 10)
“According to Assistant Secretary Narciso Inlong of the Presidential Task Force on Pinatubo, P3.8 B in infrastructure was damaged; P1.045 B in school buildings, health facilities and other public buildings; P1.14 B in roads, bridges, railway and airport facilities; and P1.6 B in water supply, irrigation and flood control facilities.”
“According to Emilia Fernandez, provincial officer of the Department of Social Welfare and Development, 56,510 families or 273,793 persons were displaced; 18,345 houses were totally damaged and 18,504 were partially damaged in Zambales.” (as cited in Garcia, 1991, p.10) In Tarlac, 4,404 families or 25,472 persons were displaced by lahar and flashfloods and 1,507 families or 7,075 people were displaced by the eruption. In Pampanga, 50,000 persons were displaced by the eruption.
Lahar also threatened a multi-million gold mining site near Marella River in Barangay Dalanaon which displaced 600,000 persons from their jobs.
A total of 737 people have died, 195 more were injured and 24 were reported missing. About half or 339 deaths were caused by various diseases in the cramped evacuation centers. 90% of the casualties were children up to 4 years old, whom died from malnutrition and diseases arising from their lack of immunization. (Dacanay, 1991, p.15)
Preparations Prior to Eruption
Scientists from PHILVOLCS have monitored Pinatubo’s activities since it has shown signs of eruption. Seismic monitoring was stationed on different villages near the volcano. Lahar flow detectors and other apparatus necessary for data gathering were installed several days prior to eruption. Evacuation centers were prepared for the evacuees. The government prepared funds for foods, clothing, medicines and other necessary things needed for both the people affected by the eruption and lahar and those that were in the evacuation centers. Rescue aids were on alert. Non-government groups helped in raising funds. Others volunteered to assist the victims and survivors. Corresponding high alert levels were announced on areas to which according to PHILVOLCS will be dangerous upon and after eruption. Families living within the critical areas were forced to leave. Many of them stayed in the evacuation centers. Others stayed with their relatives. The mandate for forced evacuation was carried by the Armed Forces of the Philippines.
Approximately 16,000 Americans working in the Clark Air Base and their 20,000 dependents were evacuated and were sent back home. The damage that the eruption made was so expensive that the U.S. government decided not to go back and rehabilitate the base.
Few days after the eruption, residents and the government helped in cleaning away the ashes and debris. Bulldozers and dump trucks were used to carry away the ashes and debris on the streets and highways. The government relocated the homeless. The ashes and debris were used to build their new houses. Seminars, trainings and therapies were held for the survivors and victims. In cooperation of different private organizations, the government started different livelihood programs for the jobless. One of which was making money out of the ashes and debris. The ashes and debris were used and formed into figurines and souvenirs. The project did not only help the victims financially but emotionally as well. Their projects were sold in all parts of the Philippines. It even reached other countries.
With years, buildings, roads, bridges and other infrastructures were erected again. But the areas covered by thick mud were left as they were. Reforestations slowly brought back the trees.
The eruption of Pinatubo, indeed, was so devastating. It killed 737 people, 195 more were injured and 24 were reported missing. Hundreds of thousands were left homeless. Hundreds of thousands of hectares of land were affected and will not be used for years. Both plants and animals have died. And hundreds of billions of peso worth of properties were destroyed.
Globally, it affected the temperature. It depleted the ozone layer. It caused what the scientist called regional nuclear winter.
- Avedaño, C. O. (1991, December 17). Grim numbers tell only half the story. Philippine Daily Inquirer, pp. 1,8.
- Basa, B. (1991, December 17). Tarlac: Even aquino’s home province wasn’t spared. Philippine Daily Inquirer, p. 10.
- Dacanay, B. M. (1991). Mount pinatubo: 500 years after. Quezon City: Mass Media Publishing Corporation.
- Garcia, R. (1991, December 17). Zambales: Rampaging lahr imperils 6 towns. Philippine Daily Inquirer, p. 10.
- Newhall, C., Stauffer, P. H. & Hendley II, J. W. (1997). Lahars of mount pinatubo, philippines.
- U.S. Geological Survey Fact Sheet 114-97, Online Version. Retrieved November 28, 2006, from http://pubs.usgs.gov/fs/1997/fs114-97/.
- Steam, quakes, ash and dome: Pre-eruption manifestations of pinatubo. Retrieved November 28, 2006, from http://park.org/Philippines/pinatubo/page3.html.