LIFE AFTER

Inconspicuously nestled in the dense forest of Northern Luzon’s Cabusilan Sierras, Mt. Pinatubo’s 1991 massive eruption gave notice to its presence around the globe.

Lying dormant for centuries, Mount Pinatubo is located near the provinces of Zambales, Pampanga and Tarlac. Its climactic eruption on June 15, 1991 was second in size to the 1912 eruption in Katmai, Alaska, but ten times larger than the 1980 eruption of Mt. St. Helen's in Washington. Its giant ash cloud rose to over 35 kilometers into the sky.

The climactic eruption leveled off 300 m of the volcano's 1,745 m high summit. In its place is a 2 km-diameter caldera, the center of which is slightly northwest of the preeruption summit. Tephra or volcanic fragment deposits covered a land area of about 4,000 square kilometers surrounding Pinatubo.

These deposits buried farm lands and took hundreds of lives when the torrential monsoon rains fell soaking ash laden roofs and was aggravated by the arrival of Typhoon Yunya (Diding). The typhoon brought heavy rain and strong winds that aided in dispersing tephra falling from the broad stratospheric eruption cloud. Valleys that had been carved by prehistoric eruptions of Mount Pinatubo were partly filled again.   

  

For hours typhoon Yunya assisted in sweeping the ash to a higher elevation during the most violent phase of the eruption.

The ash cloud covered an area of some 125,000 km², bringing total darkness to much of central Luzon. This event was called “Black Saturday”. Almost all of the island of Luzon received some ash fall, which formed a heavy, rain-saturated snow-like blanket. Tephra fell over most of the South China Sea and ash fall was recorded as far away as Indonesia, Vietnam, Thailand and Malaysia.  

      

As early as March, tremors had already been felt within Mt. Pinatubo's vicinities. The first magmatic eruptions started on June 3, followed by minor ash eruptions from June 9-11, and the major eruptions occurred on June 12-16 having the climactic phase on June 15. 

Mt. Pinatubo ejected roughly 10,000,000,000 tons of magma, and 20,000,000 tons of Sulfur Dioxide. It spewed vast quantities of minerals and metals to the surface such as zinc, copper, chromium, nickel, and massive amounts of toxic heavy metals such as lead, arsenic, cadmium, and mercury.      

Pinatubo’s eruption was felt across the globe due to the large amounts of aerosol it added into the stratosphere – more than any eruption since that of Krakatoa in 1883. For months, the aerosols formed a global layer of sulfuric acid haze. Global temperatures dropped by about 0.5 °C, and ozone depletion temporarily increased substantially.

As early as April, preeruption signs were already observed. The Philippine Institute
of Volcanology and Seismology (PhilVocs) with the aid of the U.S. Geological Survey (USGS) were able to predict the eruption aiding the local government evacuate thousands of people from Pinatubo's the slopes and valleys, while the U.S. military airlifted thousands of their personnel and their dependents from Clark Air Force Base and Subic Naval Base saving lives and costly property. Both bases were ultimately abandoned by the United States military. This evacuation was later recognized as a huge success for volcanology and eruption prediction in history.

However, even with timely precautions, road and communication infrastructures were destroyed, communities, reforestation projects, rice land, livestock, and poultry, and the livelihoods of

thousands of farmers were not spared.

Each onset of heavy rain brought lahars or debris flow composed of slurry pyroclastic material, rocky debris, and water from the mountain range, causing the displacement of thousands of people inflicting extensive damage to buildings and infrastructure.

Damage to healthcare facilities, and the spread of illnesses in relocation facilities due to poor sanitation, led to rising death tolls in the months to come. Less than 900 people died mostly from the evacuation centers. Still people continued to live within 40 km of the mountain, with population centers in Angeles City, and Clark Freeport Zone.

Weaker but still spectacular eruptions of ash continued

through early September 1991. From July to October 1992, a lava dome formed in the new caldera as fresh magma rose from beneath Pinatubo.

   

Several important river systems stem from Mount Pinatubo, with the major rivers being the Abacan, Tarlac, Pasig-Potrero, Sta. Lucia, Bucao, Santo Tomas, Maloma, Tanguay, Ashley, and Kileng rivers. Its eruption clogged these rivers with sediment, and the valleys with deep pyroclastic deposits have collected lahars in the following years. 

Farmers near Pinatubo began growing root crops such as peanuts, cassava and sweet potatoes, which ripens fast and could be harvested before the threat of lahar flows during the rainy season.

 

 ERUPTIONS

 

  

 CALDERA TRANSFORMATION

 

 

After being driven away by the Spanish colonizers from the lowlands the Aetas took refuge in the Cabusilan Sierras, but was driven out again by Mt. Pinatubo's 1991 eruption. On January 2010, Aetas from Zambales were officially granted the Ancestral Domain Titles covering the Zambales side of Pinatubo including the summit and Lake Pinatubo. The ancestral domain title covers 15,984 hectares covering the villages of Burgos, Villar, Moraza and Belbel in Botolan and portions of the towns of Cabangan, San Felipe and San Marcelino.

(all photos above were taken from google images)

Having been absent in the country during this catastrophe, for years I have been intrigued by the stories I’ve heard from friends reminiscing their treks and camp outs at Mt. Pinatubo. Finally, after decades of postponing visiting the site, I finally decided to join a group headed for Mt. Pinatubo organized by Tripinas.

Considering the heat and terrain, I prepared my trekking gear a few days before: trekking sandals, tropical rip-stop army cargo pants, light long sleeved shirt, parka, breathable cap with side skirts, sunglasses, sun block, a swiss knife, flashlight, sarong and a day backpack with three water bottles, 4 sandwiches, hardboiled eggs and trail mix, towel, soap and spare light clothes.

Our group met 3:00 in the morning at McDonald’s, corners Quezon Avenue and EDSA.  After our registration and briefing, we boarded our designated vans and headed north to NLEX exiting at the Dao toll way.

We briefly stopped by a convenient store for last minute supplies, then proceeded to Barangay Juliana in Capas, Tarlac where 4x4 vehicles of all shapes, make and models lay await. A maximum of five passengers per off-roader was assigned. Our vehicle was a modified Mitsubishi “Jeep” adapted to the lahar and tephra riddled terrain enroute to the foothills of Mt. Pinatubo.

At the break of dawn, our group sped southeast racing through a vast river bed covered with damp lahar. Our vehicle would slow down for shallow streams crossing our path and at times crawl on deeper rock hewn creeks. A real treat it was.

After an hour of off-roading we reached Mt. Pinatubo’s visitors parking area. Since it was still early in the morning, the climate was still cool and the walls flanking the gorge served as shades at certain points of the trail. Loose rocks, lahar, and water filled the trail reminding me of the term “watch your steps”.

The landscape was more than I expected, AWESOME! The river trail though mostly barren, had plants growing on top of the tephra walls. A far site from what it was 21 years ago. The annual rain water gushing down from Pinatubo Lake prevents plants from holding fast not enough time to grow. Evidence of sand slides was quite common. Even a strong gust of wind easily defaces the walls of the gorge. With these, new trails are remade not on the same place as previous years. 

Hot spring water trickles out of a few sites where clusters of green algae type plants mark their path. Fat centipedes crawl or lay curled up in nearby crevices.  On the upper part of the river, hot water streamed down rusty colored bed rocks. 
 

After 2 hours of a leisurely trek, we reached a rest shed just at the edge of an overgrowth marking the trail to Mt. Pinatubo’s caldera. Pushing on uphill, we continued to walk alongside a trickling stream within a mini-tropical forest. Upon reaching the top, unfolds the spectacular view of Mt. Pinatubo’s green colored lake water surrounded by its steep rim formed during its 1991 eruption.

Surprisingly, there were a number of visitors already ahead of us and more were still arriving. An open sided hall sits on the bottom of the stairway beside the lake where visitors could rest and eat their packed meals.

Row boats not bankas (canoe shaped wooden boats with outriggers) were available for rent to those who wish to traverse across the lake and back.

Swimming in the lake’s cool deep water was free. 

Pinatubo's lake is about 2.5 km wide and 800 meters deep, the deepest in the country. Although over the years rain water has filled the lake's hot acidic water still there seem to be an absence of marine life. Certain sides of the lake’s caldera have visible signs of sliding.

After an hour of swimming and enjoying

Pinatubo’s beauty by the lake shore, our group headed back. The noon time temperature was hot, but the slight breeze that flowed down the gorge helped cool down our trek. As we watched our footing, a father and son Aeta came running and leaping past us on bare feet. The elder was even carrying a sack of firewood on his back. It was amazing to see how the Aetas have adopted to this harsh environment.

Upon reaching the parking area, the 4x4 vehicles have quadrupled in number indicating that the site is indeed a “must see” destination. We boarded our jeep and enjoyed the rough ride back though dusty and wet from Mt. Pinatubo’s ashes and water.

           The drive and trek through Mt. Pinatubo’s river, foothills, gorge, and streams, swimming in its lake encircled by the towering caldera and seeing its native residents was truly an unforgettable experience. The visit has shown me a glimpse of Mt. Pinatubo’s history seeing nature grown back from its once ash-laden landscape, nature’s true testament to life after.