Mount Pinatubo is an active

stratovolcano A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with ...

in the

Zambales Mountains The Zambales Mountains is a mountain range in western Luzon. The mountains spread along a north-south axis, separating Luzon's central plain from the South China Sea. The range extends into five Provinces of the Philippines, provinces: Zambales, ...

Luzon Luzon ( , ) is the largest and most populous List of islands in the Philippines, island in the Philippines. Located in the northern portion of the List of islands of the Philippines, Philippine archipelago, it is the economic and political ce ...

in the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

. Located on the

tripoint A triple border, tripoint, trijunction, triple point, or tri-border area is a geography, geographical point at which the boundaries of three countries or Administrative division, subnational entities meet. There are 175 international tripoints ...

Zambales Zambales, officially the Province of Zambales (; ; ; ; ), is a Provinces of the Philippines, province in the Philippines located in the Central Luzon Regions of the Philippines, region. Its capital is Iba, Zambales, Iba, which is located in t ...

Tarlac Tarlac, officially the Province of Tarlac (; ; ; ; ), is a landlocked Provinces of the Philippines, province in the Philippines located in the Central Luzon Regions of the Philippines, region. It had a population of 1,503,456 people according to ...

and

Pampanga Pampanga, officially the Province of Pampanga (; ; ), is a province in Central Luzon in the Philippines. Lying on the northern shore of Manila Bay, Pampanga is bordered by Tarlac to the north, Nueva Ecija to the northeast, Bulacan to the east, ...

provinces, most people were unaware of its eruptive history before the pre-eruption volcanic activity in early 1991. Dense

forest A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...

s, which supported a population of several thousand indigenous Aetas, heavily

eroded Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust and then transports it to another location where it is deposited. Erosion is disti ...

and obscured Pinatubo. Pinatubo is known for its VEI-6 eruption on June 15, 1991, the second-largest terrestrial eruption of the 20th century after the 1912 eruption of

Novarupta Novarupta is a volcano located on the Alaska Peninsula on a slope of Trident Volcano in Katmai National Park and Preserve, about southwest of Anchorage. Novarupta was formed in 1912, during the largest volcanic eruption of the 20th century, in ...

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

. The eruption coincided with Typhoon Yunya making landfall in the Philippines, which brought a dangerous mix of ash and rain to nearby towns and cities. Early predictions led to the evacuation of tens of thousands of people, saving many lives. The eruption severely damaged surrounding areas with

pyroclastic surge A pyroclastic surge is a fluidised mass of turbulent gas and rock fragments that is ejected during some volcanic eruptions. It is similar to a pyroclastic flow but it has a lower density or contains a much higher ratio of gas to rock, which makes i ...

pyroclastic fall A pyroclastic fall deposit is a uniform deposit of material which has been ejected from a volcanic eruption or plume such as an ash fall or tuff. Pyroclastic fallout deposits are a result of: # Ballistic transport of ejecta such as volcanic bloc ...

s, and later, flooding

lahar A lahar (, from ) is a violent type of mudflow or debris flow composed of a slurry of Pyroclastic rock, pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a valley, river valley. Lahars are o ...

s caused by rainwater re-mobilizing volcanic deposits. This destruction affected infrastructure and altered river systems for years. Minor

dome A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...

-forming eruptions inside the caldera continued from 1992 to 1993. The 1991 eruption had worldwide effects. It released roughly or of magma, bringing large amounts of minerals and toxic metals to the surface. It also released of . It ejected more

particulate Particulate matter (PM) or particulates are microscopic particles of solid or liquid matter suspended in the air. An ''aerosol'' is a mixture of particulates and air, as opposed to the particulate matter alone, though it is sometimes define ...

into the

stratosphere The stratosphere () is the second-lowest layer of the atmosphere of Earth, located above the troposphere and below the mesosphere. The stratosphere is composed of stratified temperature zones, with the warmer layers of air located higher ...

than any eruption since

Krakatoa Krakatoa (), also transcribed (), is a caldera in the Sunda Strait between the islands of Java and Sumatra in the Indonesian province of Lampung. The caldera is part of a volcanic island group (Krakatoa archipelago) comprising four islands. Tw ...

in 1883. In the following months, aerosols formed a global layer of

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

haze. Global temperatures dropped by about in the years 1991–1993, and

ozone depletion Ozone depletion consists of two related events observed since the late 1970s: a lowered total amount of ozone in Earth, Earth's upper atmosphere, and a much larger springtime decrease in stratospheric ozone (the ozone layer) around Earth's polar ...

temporarily increased significantly.

Geography

The volcano is about northwest of

Manila Manila, officially the City of Manila, is the Capital of the Philippines, capital and second-most populous city of the Philippines after Quezon City, with a population of 1,846,513 people in 2020. Located on the eastern shore of Manila Bay on ...

, the capital of the Philippines. Near Mount Pinatubo are former military bases that were maintained by the United States. The U.S. Naval Base Subic Bay was south of Pinatubo, and the extent of

Clark Air Base Clark Air Base is a Philippine Air Force base in Luzon, located west of Angeles City, and about northwest of Metro Manila. It was previously operated by the U.S. Air Force and, before that, the U.S. Army, from 1903 to 1991. The base cov ...

was just east of the volcano's summit.Tactical Pilotage Chart, Sheet K-11B, Defense Mapping Agency, Department of Defense, 1982. The volcano is near to about 6 million people.

History

Even before the 1991 eruption, Mount Pinatubo had little

topographic prominence In topography, prominence or relative height (also referred to as autonomous height, and shoulder drop in US English, and drop in British English) measures the height of a mountain or hill's summit relative to the lowest contour line encircling ...

: it was above sea level, only about above nearby

plain In geography, a plain, commonly known as flatland, is a flat expanse of land that generally does not change much in elevation, and is primarily treeless. Plains occur as lowlands along valleys or at the base of mountains, as coastal plains, and ...

s, and only about higher than surrounding peaks, which largely obscured it from view. It is part of a chain of

volcanoes A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often fo ...

which lie along the western side of the island of

called the

. Pinatubo belongs to the Cabusilan sub-range of the

, which consists of Mount Cuadrado, Mount Negron, Mount Mataba and Mount Pinatubo. They are

subduction Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...

volcanoes, formed by the Eurasian plate sliding under the

Philippine Mobile Belt In the geology of the Philippines, the Philippine Mobile Belt is a complex portion of the tectonic boundary between the Eurasian plate and the Philippine Sea plate, comprising most of the country of the Philippines. It includes two subduction ...

along the

Manila Trench The Manila Trench is an oceanic trench in the Pacific Ocean, located west of the islands of Luzon and Mindoro in the Philippines. The trench reaches a depth of about , in contrast with the average depth of the South China Sea of about . It i ...

to the west. Mount Pinatubo and the other volcanoes on this

volcanic belt A volcanic belt is a large volcanically active region. Other terms are used for smaller areas of activity, such as volcanic fields or volcanic systems. Volcanic belts are found above zones of unusually high temperature () where magma is created ...

arise due to

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...

tic occlusion from this

plate boundary. Pinatubo is flanked on the west by the

Ophiolite An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle (Earth), upper mantle that has been uplifted and exposed, and often emplaced onto continental crustal rocks. The Greek word ὄφις, ''ophis'' (''snake'') is ...

Complex, which is an easterly-dipping section of

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

oceanic crust uplifted during the late

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

. The Tarlac Formation north, east and southeast of Pinatubo consists of marine, nonmarine and volcanoclastic sediments formed in the late

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

and

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58 The most recent study of Mount Pinatubo before the activities of 1991 was the overall geological study in 1983 and 1984 made by F. G. Delfin for the

Philippine National Oil Company The Philippine National Oil Company (PNOC) is an energy company created on November 9, 1973, as a government-owned and controlled corporation founded during President Ferdinand Marcos' era to supply oil to the Philippines. Since then, its cha ...

as part of the surface investigations of the area before exploratory drilling and well testing for

geothermal energy Geothermal energy is thermal energy extracted from the crust (geology), crust. It combines energy from the formation of the planet and from radioactive decay. Geothermal energy has been exploited as a source of heat and/or electric power for m ...

sources in 1988 to 1990. He recognized two life histories of the mountain, which he classified as "ancestral" and "modern" Pinatubo.

Ancestral Pinatubo

Philippine Island - Luzon Island - NARA - 68156975

Activity of Ancestral Pinatubo seems to have begun about 1.1 million years ago and probably ended tens of thousands of years or more before the birth of "modern" Pinatubo. Much of the rugged land around the present volcano consists of remnants of "ancestral" Pinatubo. It was an

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomina ...

and

dacite Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...

whose eruptive activity was much less explosive than modern Pinatubo. Its center was roughly where the current volcano is. The projected height of the mountain is up to , or 1.43 miles above

sea level Mean sea level (MSL, often shortened to sea level) is an mean, average surface level of one or more among Earth's coastal Body of water, bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical ...

if it were a lone peak, based on a profile fitting to the remaining lower slopes, or lower if it had more than one peak. The old volcano is exposed in the walls of an old wide

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...

, referred to as ''Tayawan Caldera'' by Delfin. Some of the nearby peaks are the remnants of ancestral Pinatubo, left behind when the softer parts of the old mountain slopes were eroded by

weathering Weathering is the deterioration of rocks, soils and minerals (as well as wood and artificial materials) through contact with water, atmospheric gases, sunlight, and biological organisms. It occurs '' in situ'' (on-site, with little or no move ...

. Ancestral Pinatubo is a somma volcano with modern Pinatubo as the new cone. Mount Dorst, to the east, is part of the dip slope of the ancestral Pinatubo. Several mountains near modern Pinatubo are old satellite vents of ancestral Pinatubo, forming

volcanic plug A volcanic plug, also called a volcanic neck or lava neck, is a volcano, volcanic object created when magma hardens within a Volcanic vent, vent on an active volcano. When present, a plug can cause an extreme build-up of high gas pressure if risi ...

s and lava domes. These satellite vents were probably active around the same time as the ancestral volcano and include the domes of Mount Negron, Mount Cuadrado, Mount Mataba and the Bituin and Tapungho plugs.

Modern Pinatubo

* c. 79,000 BC: After a long period of

dormancy Dormancy is a period in an organism's Biological life cycle, life cycle when growth, development, and (in animals) physical activity are temporarily stopped. This minimizes metabolism, metabolic activity and therefore helps an organism to conserv ...

, Modern Pinatubo was born in Ancestral Pinatubo's cataclysmic and most explosive eruptions, estimated to be five times larger than the June 1991 eruption. It deposited all around the volcano up to of

material up to thick. The total volume of volcanic material ejected during the eruptions is unknown. The removal of so much material from the underlying

magma chamber A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is less dense than the surrounding country rock, which produces buoyant forces on the magma that tend to drive it u ...

resulted in the Tayawan

. The violent eruptive period started by the eruption is referred to by Delfin as the ''Inararo Eruptive Period'', named after a village that was destroyed in the 1991 eruption. Later eruptions of modern Pinatubo occurred episodically and lasted for periods much shorter than the repose intervals between them. Subsequent eruptions and eruptive period occurred about: *c. 15,000 BC (Sacobia Eruptive Period) *c. 7000 BC (Pasbul Eruptive Period). Its eruptions were as energetic, if not as voluminous as the Inararo eruptions. *c. 4000–3000 BC (Crow Valley Eruptive Period). This and the Mara-unot period's eruptions were smaller than the Inararo eruptions but about two to three times as big as that of 1991 based on the pyroclastic flow runout distances and depths of valley filling. *c. 1900–300 BC (Maraunot Eruptive Period) *c. AD 1500 (Buag Eruptive Period). Its eruptions were roughly the same size as those of 1991. Each of these eruptions seems to have been very large, ejecting more than of material and covering large parts of the surrounding areas with pyroclastic flow deposits. Some eruptive periods have lasted decades and perhaps as much as several centuries and might appear to include multiple large explosive eruptions. The maximum size of eruptions in each eruptive period though has been getting smaller through the more than 35,000-year history of modern Pinatubo, but this might be an artifact of erosion and burial of older deposits. The oldest eruption of modern Pinatubo, Inararo, was also its largest. The 1991 eruption was among the smallest documented in its geologic record. The volcano has never grown very large between eruptions, because it produces mostly unwelded, easily erodible deposits and periodically destroys the viscous domes that fill its vents. After the Buag eruption (c. 1500 AD), the volcano lay dormant, its slopes becoming completely covered in dense

rainforest Rainforests are forests characterized by a closed and continuous tree Canopy (biology), canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropi ...

and eroded into gullies and ravines. The c. 500-year repose though between the Buag and present eruptive periods is among the shorter repose periods recognized in its geologic history.

1991 eruption

A small blast at 03:41 PST on June 12 marked the beginning of a new, more violent phase of the eruption. A few hours later the same day, massive blasts lasting about half an hour generated big eruption columns, which quickly reached heights of over and which generated large

s extending up to from the summit in some river

valley A valley is an elongated low area often running between hills or mountains and typically containing a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams over ...

s. Fourteen hours later, a 15-minute blast hurled volcanic matter to heights of . Friction in the up-rushing ash column generated abundant

volcanic lightning Volcanic lightning is an electrical discharge caused by a volcanic eruption rather than from an ordinary thunderstorm. Volcanic lightning arises from colliding, fragmenting particles of volcanic ash (and sometimes ice), which generate static elec ...

. In March and April 1991, magma rising toward the surface from more than beneath Pinatubo triggered small volcano tectonic earthquakes and caused powerful steam explosions that blasted three craters on the north flank of the volcano. Thousands of small earthquakes occurred beneath Pinatubo through April, May and early June and many thousand of tons of noxious

sulfur dioxide Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is r ...

gas were also emitted by the volcano. From June 7 to 12, the first magma reached the surface of Mount Pinatubo. Because it had lost most of the gas contained in it on the way to the surface, the magma oozed out to form a lava dome but did not cause an explosive eruption. However, on June 12, millions of cubic yards of gas-charged magma reached the surface and exploded in the reawakening volcano's first spectacular eruption. When even more highly gas-charged magma reached Pinatubo's surface on June 15, the volcano exploded in a cataclysmic eruption that ejected more than of material. The

ash cloud Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcano, volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used ...

from this climactic eruption rose into the atmosphere. At lower altitudes, the

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...

was blown in all directions by the intense cyclonic winds of a coincidentally occurring typhoon, and winds at higher altitudes blew the ash southwestward. A blanket of ash and larger

pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicula ...

lapilli Lapilli (: lapillus) is a size classification of tephra, which is material that falls out of the air during a volcanic eruption or during some meteorite impacts. ''Lapilli'' is Latin for "little stones". By definition lapilli range from in dia ...

blanketed the countryside. Fine ash fell as far away as the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

and satellites tracked the ash cloud several times around the globe. Huge pyroclastic flows roared down the flanks of Mount Pinatubo, filling once-deep valleys with fresh volcanic deposits as much as thick. The eruption removed so much magma and rock from below the volcano that the summit collapsed to form a wide caldera. Following the climactic eruption of June 15, 1991, activity at the volcano continued at a much lower level, with continuous ash eruptions lasting until August 1991 and episodic eruptions continuing for another month. Tephra fall from 1991 eruption of Mt Pinatubo

Tephra fall from 1991 eruption of Mt Pinatubo

Later eruptions

Activity at the volcano remained low until July 1992 when a new lava dome started growing in the

. Volcanologists suspected that further violent eruptions could be possible, and some areas were evacuated. However, the eruption was only minor. The last eruption of Mount Pinatubo took place in 1993.

Lake Pinatubo

The 1991 caldera afterwards filled with water from annual monsoon rains and a crater lake, Lake Pinatubo, was formed. In 1992, a growing lava dome formed an island, which was eventually submerged by the lake. Initially, the lake was hot and highly

acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...

ic, with a minimum pH of 2 and a temperature of about . Subsequent rainfall cooled and diluted the lake, lowering the temperature to and raising the pH to 5.5 by 2003. The lake deepened by about per month on average, eventually submerging the lava dome, until September 2001, when fears that the walls of the crater might be unstable prompted the Philippine government to order a controlled draining of the lake. An estimated 9,000 people were once again evacuated from surrounding areas in case a large

flood A flood is an overflow of water (list of non-water floods, or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are of significant con ...

was accidentally triggered. Workers cut a notch in the crater rim and drained about a quarter of the lake's volume.

Recent activity

On July 10, 2002, the west wall of the crater collapsed, slowly releasing approximately of water and sediment into the Maraunot River in Botolan, Zambales. On July 26, 2011, a 5.9 magnitude earthquake struck close to Pinatubo; however, no major damages or casualties were reported. On March 4, 2021, the PHIVOLCS raised alert level 1 over Mount Pinatubo after reporting an increase on its seismic activity. 1,722 volcanic earthquakes were also recorded within the vicinity of the volcano since January 2021. On August 11, 2021, PHIVOLCS downgraded Mt. Pinatubo's Alert Level 1 to Level 0, due to "continued decrease in earthquake activity and a return to baseline seismic parameters". PHIVOLCS said it noted a "significant decrease" in volcanic earthquakes, with a total of 104 quakes or an average 2–3 events per day recorded from July 1 – August 1, 2021. On November 30, 2021, PHIVOLCS reported a weak explosion occurred on Mt. Pinatubo between 12:09 p.m. and 12:13 p.m., which produced a plume. The agency later confirmed it was a phreatic explosion produced by

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

fluids near the surface, rather than a magmatic eruption.

Cultural history

The word ''pinatubo'' could mean "fertile place where one can make crops grow", or could mean "made to grow", in

Sambal Sambal is an Indonesian chili sauce or paste, typically made from a mixture of chillis with secondary ingredients such as shrimp paste (terasi), garlic, ginger, shallot, scallion, palm sugar, and lime juice. ''Sambal'' is an Indonesia ...

and Tagalog, which may suggest a knowledge of its previous eruption in about 1500 AD. There is a local oral tradition suggestive of a folk memory of earlier large eruptions. An ancient legend tells of Bacobaco, a terrible spirit of the sea, who could metamorphose into a huge turtle and throw fire from his mouth. In the legend, when being chased by the spirit hunters, Bacobaco flees to the mountain and digs a great hole in its summit showering the surrounding land with rock, mud, dust and fire for three days; howling so loudly that the earth shakes.

History among Aetas

Aeta Aeta (Ayta ), Agta and Dumagat, are collective terms for several indigenous peoples who live in various parts of Luzon islands in the Philippines. They are included in the wider Negrito grouping of the Philippines and the rest of Southeast A ...

elders tell many stories about the history of the mountain, the best known being that it was once a Batung Mabye (

Kapampangan language Kapampangan, Capampáñgan, or Pampangan, is an Austronesian language, and one of the eight major languages of the Philippines. It is the primary and predominant language of the entire province of Pampanga and southern Tarlac, on the southern p ...

for "living stone"). It was said to have been planted on a kingdom by a displeased sorcerer but relocated by a hero. The mountain was soon turned into the abode of Apo Namalyari ("The lord of happenings/events"), the pagan deity of the

, Aetas and Kapampangans living on the Zambales range. It was said to comprise the whole mountain range until Sinukuan of

Mount Arayat Mount Arayat is an isolated, potentially active stratovolcano in the Central Luzon plains. Located within the vast agricultural lands of Pampanga, it rises to a height of above sea level. Its southern half lies within the municipality of A ...

(the god of the Kapampangans) became a strong rival of Namalyari. Their fight, which took place over the center plains, shattered the mountain into smaller bodies and Mount Arayat lost its center peak. Other versions have it that Pinatubo's peak shattered because of Namalyari's immense fury in an attempt to teach humans the meaning of fear and show how misdeeds will be punished. According to the native elders, Apo Namalyari induced the June 1991 eruption because of displeasure toward illegal loggers and

executives who performed deep exploratory drilling and well testing on the volcano looking for geothermal heat from 1988 to 1990. Discouraging results from the wells forced the abandonment of the prospect 13 months before the April 2, 1991, explosions.

Aetas granted ownership of Pinatubo

After being driven away by the 1991 eruption of Mount Pinatubo, in May 2009 some 454 Aeta families in Pampanga were given the first clean ancestral land ownership on Mount Pinatubo with the Certificate of Ancestral Domain Title (CADT) by the National Commission on Indigenous Peoples (NCIP), the government agency that deals with issues concerning indigenous people of the Philippines. The approved and declared net land area of covers the

barangay The barangay (; abbreviated as Brgy. or Bgy.), historically referred to as ''barrio'', is the smallest Administrative divisions of the Philippines, administrative division in the Philippines. Named after the Precolonial barangay, precolonial po ...

s of Mawakat and Nabuklod in Floridablanca, Pampanga, plus a portion of

San Marcelino, Zambales San Marcelino, officially the Municipality of San Marcelino (; ), is a municipality in the province of Zambales, Philippines. According to the 2020 census, it has a population of 37,719 people. Etymology The town got its name after the first ' ...

, and a portion of Barangay Batiawan in

Subic, Zambales Subic, officially the Municipality of Subic (; , Kapampangan: ''Balen ning Subic''), is a municipality in the province of Zambales, Philippines. According to the 2020 census, it has a population of 111,912 people. Etymology The native Zamba ...

. On January 14, 2010, some 7,000 Aeta families from Zambales were officially granted the Certificate of Ancestral Domain Title (CADT) covering the Zambales side of Pinatubo which includes the summit and Lake Pinatubo, officially becoming their ''lutan tua'' (ancestral land). The ancestral domain title covers and includes the villages of Burgos, Villar, Moraza and Belbel in Botolan and portions of the towns of Cabangan, San Felipe and

San Marcelino San Marcelino, officially the Municipality of San Marcelino (; ), is a municipality in the province of Zambales, Philippines. According to the 2020 census, it has a population of 37,719 people. Etymology The town got its name after the first ' ...

. Ancestral domain titles are awarded to a certain community or indigenous group who have occupied or possessed the land continuously in accordance with their customs and traditions since time immemorial. They have the legal right to collectively possess and to enjoy the land and its natural resources to the exclusion of others. Having the land title will protect them from others – including foreigners – exploiting their land without compensation to and consent from the indigenous tribes. In the past, the Aetas had to contend with mining companies, loggers, and recently, tourist companies who earn from Mount Pinatubo but do not compensate the local tribes.Valdez, Katrina Mennen A. (January 14, 2010)
"Aetas to receive title to domain at Mt. Pinatubo"
. Preda Foundation. Retrieved on August 14, 2011.

In popular culture

Long before Mount Pinatubo became famous for its cataclysmic eruption,

Philippine president The president of the Philippines (, sometimes referred to as ) is the head of state, head of government and chief executive of the Philippines. The president leads the executive branch of the Philippine government and is the commander-in- ...

Ramon Magsaysay Ramon del Fierro Magsaysay Sr. (August 31, 1907 – March 17, 1957) was a Filipino statesman who served as the seventh President of the Philippines, from December 30, 1953, until his death in an 1957 Cebu Douglas C-47 crash, aircraft disast ...

, a native of Zambales, named his C-47 presidential plane ''Mt. Pinatubo''. The plane crashed into

Mount Manunggal Mount Manunggal is the third-highest peak in the island of Cebu after Osmena Peak and Lugsangan Peak. It is located in Barangay Magsaysay in Balamban, Cebu province, rising above sea level. It is the site of the crash of the presidential plane ...

Cebu province Cebu ( ; ), officially the Province of Cebu (; ), is a province of the Philippines located in the Central Visayas region, and consists of a main island and 167 surrounding islands and islets. The coastal zone of Cebu is identified as a ...

in 1957, killing the president and twenty-four others on board. The shape of Mount Pinatubo's caldera inspired New Clark City Athletics Stadium in

Capas Capas, officially the Municipality of Capas (; ), is a Philippine municipality, municipality in the Philippine province, province of Tarlac, Philippines, and one of the richest towns in the province. The town also consists of numerous subdivi ...

Hiking activity

The caldera formed and Lake Pinatubo has, since June 15, 1991, become a tourist attraction with the preferred route through Barangay Santa Juliana in Capas, Tarlac.

Biodiversity

Mammals

The Long-nosed forest mouse ( Apomys sacobianus) is a species of

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

endemic to Mount Pinatubo, Philippines. The Zambales forest mouse ( Apomys zambalensis) is a species of

endemic to Zambales Mountain Range, Philippines.

Notes

References

* * Decker, R. and Decker, B. (1997) ''Volcanoes'', 3rd edition, WH Freeman, New York. * * * * * * * * Dhot, S. Mt Pinatubo Safety.

External links

''Fire and Mud: Eruptions and Lahars of Mount Pinatubo, Philippines''

United States Geological Survey The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on Mar ...

site
"Weather effects of the 1991 eruption"
EOS Volcanology.
"The Cataclysmic 1991 Eruption of Mount Pinatubo, Philippines"
United States Geological Survey site

Entry for Pinatubo
in the Smithsonian Institution's Global Volcanism Program (GVP) {{DEFAULTSORT:Pinatubo, Mount * Active volcanoes of the Philippines Calderas of Southeast Asia Landforms of Pampanga Landforms of Tarlac Landforms of Zambales Mountains of the Philippines Stratovolcanoes of the Philippines Subduction volcanoes VEI-6 volcanoes Volcanic crater lakes Volcanoes of Luzon Holocene stratovolcanoes Pleistocene stratovolcanoes Zambales Mountains