PINATUBO: THE HUGE 1991 ERUPTION, DAMAGE, LAHARS, GLOBAL CLIMATE

PINATUBO

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Pinatubo vertical eruption, 1991 Mt. Pinatubo (100 kilometers northwest of Manila and two hours by car from Angeles City) is a 1486 meter-high (4,875 feet) stratovolcano. Comprised of a complex of lava domes, it erupted catastrophically in 1991 after lying dormant for 400 years in what is considered the second most powerful volcanic event in the 20th century (the most powerful was Novarupta in Alaska in 1912). Dozens of villages were buried under tons of ash and mud. More than 800 people died during Pinatubo's eruption and more died from diseases in overcrowded evacuation camps.

Volcanologists knew very little about Pinatubo before it roared back to life in 1990-1991, Before that the last time it erupted was around the 1450s. According to volcanodiscovery.com: There were no known historic eruptions. Before the eruption in 1991 Pinatubo was 1745 meters high (about 250 meters more than now), and was only 200 meters higher than the nearby peaks, which are remnants of older volcanic edifices of Mt Pinatubo and hid it from views from distance. Pinatubo mostly noted for a failed geothermal development project. [Source: volcanodiscovery.com /*]

After the 1991 eruption, scientists (mainly from PHILVOLCS & USGS) carried out intensive fieldwork on the deposits of present-day Pinatubo to analyze its eruptive history. They distinguished at least 6 eruptive periods of modern Pinatubo, characterized by repeated, large explosive eruptions.” /*\

Websites and Sources on Volcanoes: USGS Volcanoes volcanoes.usgs.gov ; Volcano World volcano.oregonstate.edu ; Volcanoes.com volcanoes.com ; Wikipedia Volcano article Wikipedia , Smithsonian Global Volcanism Program volcano.si.edu operated by the Smithsonian has descriptions of volcanoes around the globe and a catalog of over 8,000 eruptions in the last 10,000 years.

Geology of Mount Pinatubo

Pinatubo was constructed layers of ash and broad pyroclastic sheets that weather with radial channels and canyons as water cuts down through the deposits from older eruptions. Over time the volcano has produced massive eruptions but these have been slowly eaten away by rain and erosion. You can also get some idea of its explosive history from the grey ash in some of the rivers draining the area. This is old ash from previous eruptions, constantly being eroded from the river channels and transported from the deposits of eruptions hundreds of years old. [Source: Erik Klemetti, Wired, June 7, 2016]

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valley filled in by pyroclastic flows at Pinatubo, According to volcanodiscovery.com: “Pinatubo is flanked to the west and probably underlain by by the Zambales Ophiolite Complex, an easterly-dipping section of Eocene oceanic crust which was uplifted in the late Oligocene. The second unit are sediments of the Tarlac Formation, mostly sandstone and siltstone in the older parts, and conglomerates and volcanic sediments and dikes in the younger. The Tarlac formation is found in the north, east and southeast of Pinatubo and formed contemporary with the oldest known volcanic centers in the area, including Mount Mataba or the diorite of the Dizon Mine, the sub-surface remnant of an ancient vent. The ancient volcanoes of the Tarlac Formation originated from the same east-dipping subduction along the Manila trench that continues to the present. [Source: volcanodiscovery.com /*]

“Ancient Pinatubo: Pinatubo was formed in 2 stages. The ancestral Pinatubo started to form about 1 million years ago, and built an andesite - dacite stratovolcano whose center was at the same location as today. Remnants of this precessor are seen in the ancient 3.5x4.5 wide caldera. Ancient Pinatubo had a number of flank vents, that formed the domes of Mount Negron, Mount Cuadrado, Mataba, Bituin plug, and the volcanic plug of Tapungho. Deep erosion in the Sacobia, Porac, Marimla, and Porac River valleys, and weathering of the lavas suggests that activity of the ancestral volcano ended several tens of thousands of years (or more) before the caldera-forming eruption and initial growth of the modern Pinatubo (ca. 35,000 years ago). /*\

Past Eruptions of Mount Pinatubo

Pinatubo has had at least 6 periods of activity with large explosive eruptions in its past 35,000 years prior to the 1991 eruption. The 1991 eruption in this context actually ranks as one of the smaller eruptions. An eruption, which occurred 35,000 years ago and probably created the caldera, was likely much bigger. Pinatubo volcano eruptions: 1992, 1991 (Plinian eruption), 1450 ± 50 years, 1050 B.C. ± 500, 3550 B.C. (?), 7030 B.C. ± 300, 7460 B.C. ± 150, 15,000 B.C., 33,000 B.C. [Source: [Source: volcanodiscovery.com /*]

1) Inararo Eruptive Period — more than 35,000 14C yr B.P. The largest eruption in the history of modern Pinatubo occurred 35,000 (radiocarbon) years ago. It deposited up to 100 m or more of pumice and ash flows on all sides of Mount Pinatubo. 2) Sacobia Eruptive Period — ~17,000 yr B.P. A phase of explosive eruptions occurred 17,000 years ago and produced 2 debris flow deposits which are visible on the north bank of the Sacobia River.

Pinatubo, June 19913) Pasbul Eruptive Period — ~9,000 yr B.P. A large explosive eruption occurred ca. 9000 years ago. It produced pyroclastic-flow and tephra-fall layers exposed along the road between Sitio Pasbul, Camias, Porac, and the Gumain River. The pyroclastic flows overtopped the southeastern rim of the Tayawan caldera and nearly or completely filled the valley of the Gumain River.

4) Crow Valley Eruptive Period — ~6,000-5,000 yr B.P. Large eruptions 6,000-5,000 years ago produced pyroclastic flow deposits on both sides of upper Crow valley. 5) Maraunot Eruptive Period — ~3,900(?)-2,300 yr B.P. Eruptions in this period produced pyroclastic flows and lahars. 6) Buag Eruptive Period — ca. 1450 A.D. The last activity cycle prior to the 1991 eruption was in 1450 ± 50 AD. It produced pyroclastic flows that entered all valley of Pinatubo except the Gumain and Porac rivers.

Massive Eruption of Pinatubo in 1991

The eruption of Mount Pinatubo in June 15, 1991 was the second largest volcanic eruption of the 20th century (only Novarupta in Alaska in 1912 was bigger), and was considerably larger than the one at Mt. St. Helens. More than 1,000 people were killed. There were 847 deaths around the time of the eruption and scores died in landslides and lahars afterwards. Pinatubo left 650,000 homeless and destroyed some of the best rice-growing land in the Philippines.

The blast was strong enough knock off the top 250 meters of 1,745-meter-high, 5,770-foot-high Mt Pinatubo and make the daytime in the Philippines seem like night. One villager said it was like “a stampede of 100,000 animals.” The National Geographic journalist Noel Grove described it as "a monstrous cannon, firing a shot with effects felt around the world."

Ten cubic kilometers — 2.3 cubic miles— of ash, rock and debris was hurled into the atmosphere from Pinatubu in a three day period. This is enough material to bury the District of Columbia to a level of 150 feet. Fist-size rocks and debris rained down for weeks. The layer of ash that was deposited was described as a giant sand trap. Because the ash plume height reached more than 40 kilometers (28 miles) high and the volcano ejected more than 10 cubic kilometers of material the eruptions was classified as plinian/ultra plinian eruption style (characterized by towering gas and ash columns, massive pyroclastic flows, and the collapse of the volcano's magma chamber to form a crater or caldera) and a VEI 6 in eruption size. VEI 6 (Volcanic Explosivity Index) is a measure of the eruption's magnitude. It indicates an event that ejects at least (10 \text{ cubic kilometers}) of tephra and rock, completely altering the surrounding landscape and triggering significant global climate changes. [Source: USGS]

Pinatubo dust layer No one had any idea that Pinatubo was going to erupt with such ferocity. It had been dormant for between 460 to 500 years and the only sign that something was going to happen was gas that started leaking out of the mountain two weeks before. In Manila, ash fell that was said to be like powdered beige snow. To keep the stuff out of their eyes, pedestrians walked the streets with plastic bags stretched over their heads. But ash was not the only problem in Manila the day the volcano erupted. Around 7:00pm earthquakes hit. The exit of the lava from the mountain had left a subterranean cavern that began falling in on itself, causing shocks. In Manila, light fixtures swayed overhead and, according to Grove, “chairs felt as uncertain as liquid.”

According to USGS: Evacuations carried out saved many lives. As early as April 1991, the Philippines Institute of Volcanology and Seismology (PHIVOLCS) and USGS declared a 6-mile radius danger zone around the volcano following results from monitoring and seismicity. An imminent eruption was declared and evacuations commenced. Initial evacuations relocated 20,000 indigenous Aeta population from the slopes. Surrounding low-lying population centers also relocated. 15,000 US military personal evacuated the Clark Air Base prior to the eruption. In total the cost for evacuations, including establishment of evacuation camps and relocation centers, was approximately 2.5 billion pesos ($93 million USD). Engineering measures were put in place with the construction of dikes and dams in attempt to control lahars. These cost an estimated 4.2 billion pesos ($154 million USD). [Source: USGS]

How Pinatubo Affected the Global Climate

Material from the Pinatubo eruption was hurled 25miles (40 kilometers) into the stratosphere. Layers of dust settles at around 100,000 feet and took years to dissipate. Around 20 million tons of sulfur dioxide made its way to the stratosphere, where it combined with moisture creating a thin aerosol cloud of sulfuric acid that girdled the globe within 21 days.

The layer of sulfate aerosol scattered light sunlight and absorbed heat from the earth, cooling the planet's surface. Pinatubo caused world temperature to drop around 0.25°C on average for the next five years. . Scientists, measuring the depth of the cloud by satellite observation, calculate that 2 percent of the incoming sunlight was deflected from the earth by the layer of sulfate aerosol.

Satellite measurements of global sea level began in 1993 and provided scientists with a powerful new tool for monitoring the effects of climate change on the world's oceans. During the first two decades of satellite observations, sea levels appeared to rise at a relatively steady rate of about 3 millimeters per year. This finding puzzled researchers because many climate models had predicted that the rate of sea-level rise should be accelerating as global temperatures increased. [Source: Léa Surugue, International Business Times, August 10, 2016]

Pinatubo ash A later study published in Scientific Reports suggested that the apparent lack of acceleration may have been influenced by the 1991 eruption of Mount Pinatubo in the Philippines. The eruption injected vast quantities of volcanic aerosols into the atmosphere, where they reflected sunlight and temporarily cooled the Earth's surface. This cooling effect reduced ocean temperatures and influenced sea levels just before satellite monitoring began, potentially masking the true pace of climate-driven sea-level rise.

To investigate the issue, researchers used forty climate-model simulations to compare a world affected by the Pinatubo eruption with one in which the eruption never occurred. Their models indicated that the volcanic cooling caused global sea levels to drop by about 6 millimeters immediately before the start of satellite observations. As a result, satellite records began from an unusually low baseline, making subsequent sea-level rise appear more uniform than it actually was.

The simulations showed that without the Pinatubo eruption, satellite measurements would likely have revealed a clear acceleration in sea-level rise from the beginning of the record. Lead researcher John Fasullo noted that as the cooling effects of the eruption gradually faded, the underlying acceleration driven by global warming should become increasingly evident in satellite observations. The study highlighted the significant influence that major volcanic eruptions can have on short-term climate patterns and emphasized the importance of accounting for such events when assessing long-term changes in sea level.

Damage By Pinatubo

Families within 15 miles of the crater said that rocks as big as grapefruits came hurling down from the sky and mud flowed into the houses. Piercing the darkness was strange-colored lightning—blue, green and even red. All told 42,000 houses were destroyed, 1000 acres of cropland buried under ash, billions of dollars in economic losses and nearly 1,000 dead. American geologists, who had arrived several months, had warned the populace that a catastrophic was going to occur or it could have been a lot worse.

Most of dead were crushed by roofs that collapsed under the weight of ash or were swept away by landslides or lahars. According to USGS: Pyroclastic flows, lahars as well as the ashfall hazard all resulted in damage and casualties. The eruption cost $700 million in damage, $100 million of which was damage to 16 aircraft flying at the time of the eruption and $250 million in property with the rest a combination of agriculture, forestry and land. A complicating factor in the dispersal of ash was at the same time as the eruption, Typhoon Yunna channeled the ash from the usual dispersal out to the ocean toward the island of Luzon. This combination gave rise to wet ash, increasing loading on structures with a large proportion of the 847 death toll due to roof collapse.[Source: USGS]

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lahar on the east side of PinatuboCarlos H. Conde wrote in the International Herald Tribune, “The spectacular eruption of the Pinatubo volcano in 1991 initially caused few casualties, thanks to the timely evacuation of almost everyone living within 30 kilometers, or about 20 miles, of the volcano. But on June 15, when the eruption reached its climax, Typhoon Yunya swept in from the Pacific, washing millions of tons of tephra—airborne ash—out of the sky. Of the 300 people killed by the initial eruption, most died when their roofs collapsed under the weight of the deposits, which fell like snow but congealed into something like concrete. Communities near Pinatubo are still suffering. Each year, heavy rains cause new flows of volcanic debris in the surrounding valleys, ruining cropland and displacing villages. [Source: Carlos H. Conde, International Herald Tribune, December 12, 2006 /]

Situated in central Luzon about 50 miles north of Manila, Clark Field sustained major damage when Mount Pinatubo erupted in 1991. The bases was decimated further when the U.S, Air Force pulled out after the eruption and looters ransacked the buildings. Clark is being transformed into a major international airport. It has two-mile-long runways that were made unusable by the ash from eruption that gets sucked into the engines during reverse thrusts and causes the ash to clog and freeze up the engines.

In August and September 2001, scientists became worried that a rain-swollen lake crater lake at Pinatubo might break through the crater walls and cause a catastrophic flood that might inundate villages and towns, killing lots of people and causing a lot of damage. Some 25 million cubic meters of water was in the lake. With great fanfare engineers dug a ditch to drain water slowly from the lake and 40,000 people below the lake were evacuated. The water dribble down the ditch in a benign, dirty, brown stream that made many people wonder what all the fuss was about. In 2004, the water in the lake suddenly turned a very dark brown and scientists tourists not drink it or swim in it. Ash from Pinatubo is now sold that is used in making building materials. Pumice stones are used in cosmetics, carpentry and washing stone washed jeans.

Buildings, Infrastructure and Agriculture Damage from the Pinatubo Eruption

The June 1991 eruption of Mount Pinatubo caused widespread destruction across Central Luzon, with heavy ashfall damaging thousands of buildings and critical infrastructure. At the former U.S. Clark Air Base, located about 20 kilometers (12 miles) northeast of the volcano, between 50 and 100 millimeters (2–4 inches) of wet ash accumulated. Water-saturated ash was particularly dangerous because of its weight, reaching densities of 1,500 to 2,000 kilograms per cubic meter. In many areas, roofs collapsed under the immense load as ash mixed with rain from Typhoon Yunya, which was passing through the region during the eruption. [Source: USGS]

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Tephra fall from 1991 eruption of Mt Pinatubo Surveys of damaged buildings found that roof design was one of the most important factors determining whether structures survived. In the town of Castillejos, 27 kilometers (17 miles) southwest of the volcano, researchers examined 51 damaged buildings. Structures with long-span roofs greater than 5 meters in width suffered the greatest losses, with 75 percent experiencing severe damage. By comparison, only 16 percent of buildings with shorter-span roofs sustained major damage. Timber-framed buildings, steeply pitched roofs, and nonresidential structures generally performed worse than reinforced-concrete and residential buildings. The principal cause of failure was the enormous weight of wet ash, which in some cases accumulated to depths of 15 to 20 centimeters and exerted loads of up to 400 kilograms per square meter.

Public infrastructure also suffered extensive damage. Within a month of the eruption, losses to transportation networks, water systems, power facilities, communications, and social infrastructure were estimated at nearly US$142 million. Water-resource facilities sustained the greatest damage, accounting for almost US$58 million, while transportation losses exceeded US$42 million. The destruction did not end with the eruption itself. In the years that followed, lahars—volcanic mudflows generated when heavy rains washed ash and debris downslope—destroyed bridges, undermined roads, and damaged additional infrastructure, causing another 1 billion pesos (approximately US$37 million) in losses.

Agriculture was among the hardest-hit sectors of the economy. About 96,200 hectares of farmland were severely affected by ashfall, with rice crops, livestock, and fisheries suffering the greatest losses. Initial damage to agriculture was estimated at 1.4 billion pesos (about US$52 million). Continued flooding, siltation, and lahar activity caused an additional 1.4 billion pesos in losses, bringing total agricultural damage to approximately 2.9 billion pesos (US$107 million) by the end of 1992. Thousands of farmers lost crops, while rivers and fishponds were buried under volcanic sediment.

The eruption also had significant environmental impacts. Approximately 18,000 hectares of forest received around 250 millimeters (10 inches) of ashfall, damaging vegetation and wildlife habitats. Efforts to reforest affected areas faced major setbacks as subsequent lahars destroyed more than 14,000 hectares of newly planted forests and seedlings. The long-lasting effects of ash deposits and mudflows continued to reshape the landscape for decades, making the 1991 Mount Pinatubo eruption one of the most destructive natural disasters in Philippine history.

Lahars at Pinatubo

Most of the damage caused by Pinatubo was produced by lahars—mudslide-like floods of rain-soaked ash—that swamped and suffocated everything in their path. Lahars on Mr. Pinatubo flowed down eight major drainage channels, passing through farmland and villages and in some cases burying entire towns in stinking, gooey mud. The fact the eruption coincided with a typhoon didn't help matters. A five-meter-high wall built to slow down lahars was overtopped by a lahar which also carved out a 20-meter foot tunnel underneath the wall.

Lahars ravaged the Pinatubo for years after the volcano erupted. Each year during the rainy season, new lahars were created that slid down slopes at speeds up to 25mph and clogged up rivers, swamped rice fields and smothered towns and villages up to 35 miles away from the volcano. Scientists believe the lahars could keep being produced well into the 21st century.

The lasting effects of the lahars is much worse than the damage caused by Mount St. Helens. During the dry season, the landscape is barren and dusty and vehicles kick up huge clouds of debris when they pass by. In the rainy season the landscape turns to muck and vehicles have to make a seven hour detour. Eight rivers have been chocked by lahars, which means the water collects in large pools of stagnant green and smelly water.

The rain also causes river filled with volcanic silt to overflow their banks and flood fields and settlements with a gooey slurry of volcanic mud and water. When the volcanic material dries it forms a material as hard as concrete that have turned once productive rice fields into vast grey deserts.

One village and all of its rice fields were swallowed up by a gooey, sticky lahar right before the harvest season was to begin. In some places around Pinatubo, the layer of volcanic ejecta, sand and peddles and boulders is 30 meters (90 feet) thick.

Damage by Pinatubo Lahars

As of 1997, 9 billion cubic meters of lahar covered the area around Pinatubo, more than a 1,000 people had been killed and 1.2 million people (10 percent of the region’s population) were left homeless as a result of lahars. In 1995, alone, more than 100,000 people were forced to evacuate their homes as a result of lahars. Hundred of millions of dollars have been lost in lost crops.

In September 1995, Bacolor, a town with 65,000 people about 25 miles from Pinatubo, was buried under more than 27 feet of volcanic sludge from a lahar in less than four hours. People were plucked off of rooftops by army helicopters after the lahar hit. For a while Bacolor was a ghost town with houses and an 18th-century church buried up to their roofs under what became volcanic concrete. About 700 people had returned to Bacolor the next year. They live in shanties and sometimes climbed through a window near the choir in the church for service and to ring the church bell which sits at ground level.

Many people displaced by the lahars live around Dapdap (60 miles from Manila), where people live in homes and along streets made from the volcanic material that destroyed their homes. Many people have lost their homes and fields. As of the late 1990s few people had jobs and many made money from begging. When they went outside they wrapped themselves like bedouins for protection from volcanic dust and grit kicked up by the winds.

The government built dikes and dams to contain the lahars, but in 1995 many of these structures were swept away by volcanic mud. In places were the dikes worked, often lahars that were directed away from one community were simply directed towards another.

One scientist told the New York Times, "During the rainy season, residents of rival villages invoke the names of their patron saints to save them from the lahar flows. It is a competition to see whose saints are more powerful with God. This has been replaced by the more mundane struggle of committees who can pull strings and reshape the engineering projects."

Aeta and Mt. Pinatubo

Many Aeta—a Negrito tribe— live or lived around Mt. Pinatubo, the volcano that erupted violently in 1991. Traditionally, the Aeta sacrificed a pig with a bottle of gin into the volcano’s crater to placate Apo Malyari, the mountain god of Mt, Pinatubo and keep who live and work around the volcano safe. Apo Malyari is regarded as a combination of smoke, fire and earthquakes. According to legend he was unjustly trapped by lava under Pinatubo and escapes ever 400 or 500 years with great eruption.

Hundreds of Aeta died during and after the eruption of Mt. Pinatubo. Some of them died in the eruption itself. Others starved from a lack a food. Some of those who resettled in evacuation camps died of measles and other lowland diseases for which they had no immunity. Most of those that remained or were left behind in the villages died. Many who chose to hide out in caves rather than evacuate also died. The survivors were mainly those who evacuated far enough to get out of harms way.

The way of life of Aeta was dramatically changed after the eruption. The villages where they used to live are under meters of ash; trees that provided shade from the hot sun are gone; and their hunting grounds were closed. Many moved back to the mountain and grew what crops they could. The sandy soil made that difficult. Mountain rice turned yellow and withered when planted in the ash. Banana trees were about the only food sources that did well. But the Aeta complained they couldn’t live on bananas alone.

Many Aeta remained in evacuation centers that looked like refugee camps. In the 1990s they wore Western cloths, worked as laborers, collected banana blossoms and bartered the for rice, and attended classes that aimed to teach them how to make handicrafts.

How Pinatubo Transformed the Lanscape Around It

The 1991 eruption of Pinatubo dramatically transformed the landscape of Central Luzon. Satellite images taken about a year after the eruption revealed vast areas that had changed from green vegetation to gray volcanic wastelands. Near the newly formed crater, enormous deposits of pyroclastic material—including ash, pumice, volcanic rocks, and other debris—covered the slopes. River valleys throughout the region were filled with thick layers of volcanic sediment carried by lahars, or volcanic mudflows, which became one of the eruption's most destructive long-term consequences. [Source: Erik Klemetti, Wired, June 7, 2016]

The eruption deposited more than five cubic kilometers of volcanic debris across the surrounding landscape, an immense volume of material. To illustrate the scale, this amount would be enough to cover the entire U.S. state of Rhode Island with approximately two meters (6.5 feet) of concrete. Seasonal rains repeatedly remobilized the ash and debris, generating lahars that flowed through river systems for decades after the eruption. In low-lying areas, these mudflows spread out across broad plains, burying farmland, roads, and communities beneath layers of volcanic sediment. Despite the extensive damage, satellite imagery also showed that large portions of the surrounding region remained green, demonstrating that even one of the twentieth century's largest eruptions had a geographically limited impact.

By 2003, only twelve years after the eruption, the recovery of the landscape was already clearly visible. Images taken from the International Space Station showed vegetation reclaiming much of the terrain that had been buried by ash and pyroclastic deposits. While major river channels remained gray because they continued to transport volcanic sediment downstream, many areas that had appeared barren in 1992 had become green once again. Some of the volcanic material had even been carried into the sea, but scientists noted that erosion would continue moving Pinatubo's 1991 deposits through river systems for centuries.

The transformation became even more remarkable by 2016, twenty-five years after the eruption. High-resolution satellite imagery showed that most of the area around the volcano had recovered substantial vegetation cover. Gray ash and debris remained visible mainly where rivers had cut through older deposits, exposing the volcanic layers beneath. At the summit, the 1991 eruption had created a caldera approximately 2.5 kilometers across. Over time, rainwater accumulated within the crater, forming a picturesque crater lake that became one of the region's most popular tourist attractions.

The recovery of Mount Pinatubo demonstrates the resilience of both natural ecosystems and human communities. Within a quarter-century, an area devastated by one of the most powerful volcanic eruptions of modern times had been largely reclaimed by vegetation and adapted for tourism and recreation. Although evidence of the eruption remains visible in river valleys and volcanic deposits, the landscape today bears little resemblance to the ash-covered terrain that existed immediately after 1991. The story of Pinatubo illustrates how quickly environmental recovery can occur even after a major geological catastrophe, while also highlighting the long-lasting influence of volcanic activity on the land.

How the Pinatubo Volcano Mouse Survived the Eruption

The Pinatubo volcano mouse, Apomys sacobianus, is a small rodent found only on and around Mount Pinatubo in the Philippines. Before 1991, the species was known from a limited area on the volcano's upper slopes and near the Sacobia River. Because of its restricted range, scientists feared that the mouse had been driven to extinction when Mount Pinatubo erupted in June 1991. The eruption was one of the largest volcanic events of the twentieth century, covering the landscape in thick ash, generating massive pyroclastic flows, and destroying much of the mountain's vegetation and wildlife habitat. [Source: Field Museum, New York Times, February 6, 2021]

For many years after the eruption, little was known about the fate of the species. Researchers assumed that the devastation had wiped out the mouse's entire habitat. However, during biological surveys conducted between 2011 and 2012, a team led by Filipino mammalogist Danny Balete returned to Mount Pinatubo to study ecological recovery in the region. To their surprise, they not only rediscovered the Pinatubo volcano mouse but found that it had become the most abundant native mammal on the mountain. Rather than disappearing, the species had survived the eruption and successfully recolonized the recovering landscape.

The survival of the Pinatubo volcano mouse is regarded as a remarkable story of wildlife survival, adaptability and evolution. Scientists believe its success is linked to its adaptation to disturbed environments. The species is considered a "disturbance specialist," meaning it thrives in habitats that have been altered by natural events such as volcanic eruptions, landslides, and storms. Although the 1991 eruption likely caused substantial losses, the newly formed landscape offered ideal conditions for recovery. Open ground, regenerating vegetation, and reduced competition from other species allowed the mice to expand rapidly as the ecosystem rebuilt itself.

The Pinatubo volcano mouse also benefits from its flexible feeding habits. It is an opportunistic omnivore that spends much of its time foraging for earthworms, insects, seeds, and other available food sources. This adaptability enables it to survive in environments where food supplies may be unpredictable. Many small mammals native to Luzon have evolved under conditions shaped by frequent typhoons, earthquakes, landslides, and volcanic eruptions, giving them a resilience that helps them withstand natural disasters.

Image Sources: Wikimedia Commons

Text Sources: New York Times, Washington Post, Los Angeles Times, Times of London, Lonely Planet Guides, Library of Congress, Philippines Department of Tourism, Compton’s Encyclopedia, The Guardian, National Geographic, Smithsonian magazine, The New Yorker, Time, Newsweek, Reuters, AP, AFP, Wall Street Journal, The Atlantic Monthly, The Economist, Foreign Policy, Wikipedia, BBC, CNN, and various books, websites and other publications.

Last updated May 2026