Mount Pinatubo

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Mount Pinatubo
Mt Pinatubo trekking - panoramio (5).jpg
Mount Pinatubo crater lake in 2012
Highest point
Elevation
  • 1,486 m (4,875 ft) (current)
  • 1,745 m (5,725 ft) (before 1991 eruption)
Listing Active volcanoes in the Philippines
Coordinates 15°08′30″N120°21′00″E / 15.14167°N 120.35000°E / 15.14167; 120.35000
Naming
Language of nameTagalog
Pronunciation /ˌpiːnəˈtuːboʊ/
Geography
Philippines relief location map (square).svg
Red triangle with thick white border.svg
Mount Pinatubo
Location within the Philippines
Mount Pinatubo
Location Luzon
Country Philippines
Region Central Luzon
Provinces
Parent range Zambales Mountains
Geology
Rock age(s) Between 635,000 ± 80,000
and 1.1 ± 0.09 million years [1]
Mountain type Stratovolcano [2]
Volcanic arc/belt Luzon Volcanic Arc
Last eruption November 30, 2021 [3]

Mount Pinatubo [4] is an active stratovolcano in the Zambales Mountains in Luzon in the Philippines. Located on the tripoint of Zambales, Tarlac and Pampanga provinces, [5] [6] most people were unaware of its eruptive history before the pre-eruption volcanic activity in early 1991. Dense forests, which supported a population of several thousand indigenous Aetas, heavily eroded and obscured Pinatubo.

Contents

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 in Alaska. [7] 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 surges, pyroclastic falls, and later, flooding lahars caused by rainwater re-mobilizing volcanic deposits. This destruction affected infrastructure and altered river systems for years. [7] [8] Minor dome-forming eruptions inside the caldera continued from 1992 to 1993.

The 1991 eruption had worldwide effects. It released roughly 10  billion tonnes (1.1×1010 short tons ) or 10 km3 (2.4 cu mi) of magma, bringing large amounts of minerals and toxic metals to the surface. It also released 20 million tonnes (22 million short tons) of SO
2 . It ejected more particulate into the stratosphere than any eruption since Krakatoa in 1883. In the following months, aerosols formed a global layer of sulfuric acid haze. Global temperatures dropped by about 0.5 °C (0.9 °F) in the years 1991–1993, [9] and ozone depletion temporarily increased significantly. [10]

Geography

Mount Pinatubo relief map Mount Pinatubo Relief Map, SRTM-1.jpg
Mount Pinatubo relief map

The volcano is about 87 kilometers (54 mi) northwest of Manila, 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 37 kilometers (23 mi) south of Pinatubo, and the extent of Clark Air Base was just 14 kilometers (8.7 mi) east of the volcano's summit. [11] The volcano is near to about 6 million people. [12]

History

Even before the 1991 eruption, Mount Pinatubo had little topographic prominence: it was 1,745 m (5,725 ft) above sea level, only about 600 m (2,000 ft) above nearby plains, and only about 200 m (660 ft) higher than surrounding peaks, which largely obscured it from view. [13] It is part of a chain of volcanoes which lie along the western side of the island of Luzon called the Zambales Mountains. [14]

Pinatubo belongs to the Cabusilan sub-range of the Zambales Mountains, which consists of Mount Cuadrado, Mount Negron, Mount Mataba and Mount Pinatubo. [15] They are subduction volcanoes, formed by the Eurasian plate sliding under the Philippine Mobile Belt along the Manila Trench to the west. Mount Pinatubo and the other volcanoes on this volcanic belt arise due to magmatic occlusion from this subduction plate boundary. [16]

Pinatubo is flanked on the west by the Zambales Ophiolite Complex, which is an easterly-dipping section of Eocene oceanic crust uplifted during the late Oligocene. The Tarlac Formation north, east and southeast of Pinatubo consists of marine, nonmarine and volcanoclastic sediments formed in the late Miocene and Pliocene. [17]

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 as part of the surface investigations of the area before exploratory drilling and well testing for geothermal energy sources in 1988 to 1990. He recognized two life histories of the mountain, which he classified as "ancestral" and "modern" Pinatubo. [17] [18]

Ancestral Pinatubo

Aerial view of Mount Pinatubo before the 1991 eruption, March 1933 Philippine Island - Luzon Island - NARA - 68156975.jpg
Aerial view of Mount Pinatubo before the 1991 eruption, March 1933
Pinatubo in April 1991, approximately two months before the eruption. Pre-eruption Pinatubo.jpg
Pinatubo in April 1991, approximately two months before the eruption.

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 and dacite stratovolcano 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 2,300 m (7,500 ft), or 1.43 miles above sea level 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. [17]

The old volcano is exposed in the walls of an old 3.5 km × 4.5 km (2.2 mi × 2.8 mi) wide caldera, 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. 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 plugs 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. [17]

Modern Pinatubo

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:

Each of these eruptions seems to have been very large, ejecting more than 10 km3 (2.4 cu mi) 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. [17]

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. [17]

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 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. [17]

1991 eruption

The eruption column of Mount Pinatubo on June 12, 1991, three days before the climactic eruption Pinatubo91eruption plume.jpg
The eruption column of Mount Pinatubo on June 12, 1991, three days before the climactic eruption
View to the west from Clark Air Base of the major eruption of Pinatubo on June 15, 1991. The June 15-16 climatic phase lasted more than fifteen hours, sent tephra about 35 km (22 mi) into the atmosphere, generated voluminous pyroclastic flows, and left a caldera in the former summit region. Later dubbed Black Saturday, the day of darkness stretched for 36 hours. Eruption of Mount Pinatubo, June 15, 1991.jpg
View to the west from Clark Air Base of the major eruption of Pinatubo on June 15, 1991. The June 15–16 climatic phase lasted more than fifteen hours, sent tephra about 35 km (22 mi) into the atmosphere, generated voluminous pyroclastic flows, and left a caldera in the former summit region. Later dubbed Black Saturday, the day of darkness stretched for 36 hours.

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 19 kilometres (62,000 ft) and which generated large pyroclastic surges extending up to four kilometres (2.5 mi) from the summit in some river valleys. Fourteen hours later, a 15-minute blast hurled volcanic matter to heights of 24 km (15 mi). Friction in the up-rushing ash column generated abundant volcanic lightning.

In March and April 1991, magma rising toward the surface from more than 32 km (20 mi) 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 gas were also emitted by the volcano. [7]

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. [7]

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 5 km3 (1.2 cu mi) of material. The ash cloud from this climactic eruption rose 35 km (22 mi) into the atmosphere. At lower altitudes, the volcanic ash 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 lapilli blanketed the countryside. Fine ash fell as far away as the Indian Ocean and satellites tracked the ash cloud several times around the globe. [7]

Huge pyroclastic flows roared down the flanks of Mount Pinatubo, filling once-deep valleys with fresh volcanic deposits as much as 200 m (660 ft) thick. The eruption removed so much magma and rock from below the volcano that the summit collapsed to form a 2.5 km (1.6 mi) wide caldera. [7]

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.

The location of Mount Pinatubo and the regional ash fallout from the 1991 eruption Tephra fall from 1991 eruption of Mt Pinatubo.gif
The location of Mount Pinatubo and the regional ash fallout from the 1991 eruption

Later eruptions

Lake Pinatubo, the crater lake resulting from the 1991 eruption, pictured here in 2008 Mount Pinatubo 20081229 01.jpg
Lake Pinatubo, the crater lake resulting from the 1991 eruption, pictured here in 2008

Activity at the volcano remained low until July 1992 when a new lava dome started growing in the caldera. 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. [2]

Lake Pinatubo

An aerial view of Mt. Pinatubo and Lake Pinatubo in 2006 Mount Pinatubo 6.jpg
An aerial view of Mt. Pinatubo and Lake Pinatubo in 2006

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 acidic, with a minimum pH of 2 and a temperature of about 40 °C (104 °F). Subsequent rainfall cooled and diluted the lake, lowering the temperature to 26 °C (79 °F) and raising the pH to 5.5 by 2003.

The lake deepened by about 1 meter (3.3 ft) 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 was accidentally triggered. Workers cut a 5-meter (16 ft) notch in the crater rim and drained about a quarter of the lake's volume. [22]

Recent activity

The Mount Pinatubo (Drone footage)

On July 10, 2002, the west wall of the crater collapsed, slowly releasing approximately 160 million cubic meters (5.7×10^9 cu ft) of water and sediment into the Maraunot River in Botolan, Zambales. [23]

On July 26, 2011, a 5.9 magnitude earthquake struck close to Pinatubo; however, no major damages or casualties were reported. [24]

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. [25]

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. [26]

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. [27] The agency later confirmed it was a phreatic explosion produced by hydrothermal fluids near the surface, rather than a magmatic eruption. [28]

Cultural history

The word pinatubo could mean "fertile place where one can make crops grow", or could mean "made to grow", in Sambal 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. [29]

History among Aetas

Aeta elders tell many stories about the history of the mountain, the best known being that it was once a Batung Mabye (Kapampangan language 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 Sambal, Aetas and Kapampangans living on the Zambales range. [30]

It was said to comprise the whole mountain range until Sinukuan of Mount Arayat (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. [30]

According to the native elders, Apo Namalyari induced the June 1991 eruption because of displeasure toward illegal loggers and Philippine National Oil Company executives who performed deep exploratory drilling and well testing on the volcano looking for geothermal heat from 1988 to 1990. [31] Discouraging results from the wells forced the abandonment of the prospect 13 months before the April 2, 1991, explosions. [32]

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 7,440.1 ha (18,385 acres) covers the barangays of Mawakat and Nabuklod in Floridablanca, Pampanga, plus a portion of San Marcelino, Zambales, and a portion of Barangay Batiawan in Subic, Zambales. [33]

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 15,984 ha (39,500 acres) and includes the villages of Burgos, Villar, Moraza and Belbel in Botolan and portions of the towns of Cabangan, San Felipe and San Marcelino. [34] [35]

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. [35] 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. [35]

Hiking to Mount Pinatubo's Crater Hiking To Mount Pinatubo.jpg
Hiking to Mount Pinatubo's Crater

Long before Mount Pinatubo became famous for its cataclysmic eruption, Philippine president Ramon Magsaysay, a native of Zambales, named his C-47 presidential plane Mt. Pinatubo. The plane crashed into Mount Manunggal in Cebu province in 1957, killing the president and twenty-four others on board. [36]

The shape of Mount Pinatubo's caldera inspired New Clark City Athletics Stadium in Capas, Tarlac. [37]

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. [38]

See also

Notes

  1. ↑ "Pinatubo Volcano". The Philippine Institute of Volcanology and Seismology (PHIVOLCS). Archived from the original on January 29, 2009. Retrieved August 12, 2008.
  2. 1 2 "Pinatubo". Global Volcanism Program. Smithsonian Institution. Archived from the original on January 23, 2020. Retrieved January 23, 2020.
  3. ↑ "Pinatubo: Eruptive History". Global Volcanism Program . Smithsonian Institution . Retrieved August 31, 2021.
  4. ↑ Sambal : Bakil nin Pinatobo; Kapampangan : Bunduk/Bulkan ning Pinatubu, Bunduk ning Apu Malyari; Pangasinan : Palandey/Bulkan na Pinatubu; Ilocano : Bantay Pinatubo; Tagalog : Bundok/Bulkang PinatuboIPA: [pɪ.nɐˈtuː.boʔ]
  5. ↑ "Tarlac map". University of Texas in Austin Library. Archived from the original on July 31, 2019. Retrieved August 2, 2011.
  6. ↑ "Report of the Philippine Commission to the President, 1901 Vol. III" Archived November 30, 2016, at the Wayback Machine , pg. 141. Government Printing Office, Washington, 1901.
  7. 1 2 3 4 5 6 "The Cataclysmic 1991 Eruption of Mount Pinatubo, Philippines". Archived from the original on August 25, 2013. Retrieved April 9, 2007.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  8. ↑ Rodolfo; Umbal; Alonso. "Two Years of Lahars on the Western Flank of Mount Pinatubo: Initiation, Flow Processes, Deposits, and Attendant Geomorphic and Hydraulic Changes". USGS Publications. Archived from the original on March 16, 2012. Retrieved March 7, 2012.
  9. ↑ Stephen Self; Jing-Xia Zhao; Rick E. Holasek; Ronnie C. Torres & Joey McTaggart (1999). "The Atmospheric Impact of the 1991 Mount Pinatubo Eruption". Archived from the original on August 2, 2014. Retrieved July 25, 2014.
  10. ↑ "Mt. Pinatubo's cloud shades global climate". Science News. Archived from the original on January 7, 2012. Retrieved March 7, 2010.
  11. ↑ Tactical Pilotage Chart, Sheet K-11B, Defense Mapping Agency, Department of Defense, 1982.
  12. ↑ Philippine Census Archived September 28, 2013, at the Wayback Machine
  13. ↑ Pinatubo, Philippines Archived December 4, 2008, at the Wayback Machine
  14. ↑ "Hiking guide: Central Luzon mountains". Pinoy Mountaineer. May 19, 2008. Archived from the original on August 4, 2020. Retrieved August 21, 2020.
  15. ↑ U.S. War Department. "Report of the Philippine Commission, 1901 Vol. III"), pg. 141. Government Printing Office, Washington. Archived June 6, 2014, at the Wayback Machine
  16. ↑ Topinka, Lyn (July 13, 2009). "Description: Mount Pinatubo, Philippines". United States Geological Survey. Archived from the original on June 3, 2010. Retrieved April 18, 2010.
  17. 1 2 3 4 5 6 7 8 Newhall, Christopher G.; Punongbayan, Raymundo S., eds. (1996). "Eruptive history of Mount Pinatubo". FIRE and MUD: Eruptions and Lahars of Mount Pinatubo, Philippines. Philippine Institute of Volcanology and Seismology; University of Washington Press. ISBN   978-0-295-97585-6. Archived from the original on January 10, 2009. Retrieved October 5, 2008.
  18. ↑ Delfin, F.G.; Villarosa, H.G.; Layugan, D.B. "Geothermal Exploration of the pre-1001 Mount Pinatubo Hydrothermal System". United States Geological Survey Publications. Archived from the original on March 16, 2012. Retrieved March 7, 2012.
  19. ↑ "Photographic Record, Mount Pinatubo". United States Geological Survey. Archived from the original on August 17, 2020. Retrieved August 21, 2020.
  20. ↑ "Photo of Mount Pinatubo". Archived from the original on March 30, 2017. Retrieved December 13, 2015.
  21. ↑ Ku, Yueh-Ping; Chen, Chang-Hwa; Newhall, Christopher G.; Song, Sheng-Rong; Yang, Tsanyao Frank; Iizuka, Yoshiyuki; McGeehin, John (February 1, 2008). "Determining an age for the Inararo Tuff eruption of Mt. Pinatubo, based on correlation with a distal ash layer in core MD97-2142, South China Sea" (PDF). Quaternary International. Global Tephra Studies: John Westgate and Andrei Sarna-Wojcicki Commemorative Volume. 178 (1): 138–145. doi:10.1016/j.quaint.2007.02.025. ISSN   1040-6182.
  22. ↑ "Filipinos return as volcano lake drains". BBC News. September 7, 2001. Archived from the original on April 21, 2021. Retrieved May 25, 2010.
  23. ↑ "Timelines Page @ glassiris.info". glassiris.info. Archived from the original on December 18, 2014. Retrieved August 21, 2020.
  24. ↑ Gonzaga, Robert and Orejas, Tonette (July 26, 2011). "5.9-magnitude quake jolts households in Luzon, Metro areas" Archived August 13, 2011, at the Wayback Machine . Inquirer News.
  25. ↑ "Alert Level 1 raised in Mt. Pinatubo —PHIVOLCS". GMA News Online. Archived from the original on March 4, 2021. Retrieved March 4, 2021.
  26. ↑ Ramos, Christia Marie (August 12, 2021). "Phivolcs lifts Mt. Pinatubo alert level". INQUIRER.net. Archived from the original on August 15, 2021. Retrieved August 15, 2021.
  27. ↑ "'Weak explosion' recorded on Mt. Pinatubo but no magma activity – Phivolcs". ABS-CBN News. November 30, 2021. Archived from the original on November 30, 2021. Retrieved November 30, 2021.
  28. ↑ "PHIVOLCS confirms Mount Pinatubo phreatic eruption". GMA News. November 30, 2021. Archived from the original on November 30, 2021. Retrieved November 30, 2021.
  29. ↑ Rodolfo, K.S. & Umbal, J.V. (2008) "A prehistoric lahar-dammed lake and eruption of Mount Pinatubo described in a Philippine aborigine legend", J. Volcanol. Geotherm. Res., 176, 432–437
  30. 1 2 "Kampangan Folk : The Power and the Glory" (PDF). Singsing. 3 (2). ISSN   1655-6305. Archived (PDF) from the original on November 10, 2013. Retrieved July 4, 2013.
  31. ↑ Loeb, Vernon (July 21, 1991). "Natives Who Worship Pinatubo Feel Its Wrath". The Seattle Times . Archived from the original on November 18, 2011. Retrieved November 22, 2008.
  32. ↑ Delfin Jr., F.G., Villarosa, H.G.. "Geothermal Exploration of the pre-1991 Mount Pinatubo Hydrothermal System" Archived November 18, 2011, at the Wayback Machine . USGS. Retrieved on August 14, 2011.
  33. ↑ (2009-05-27). "Aetas in Pampanga awarded first clean title of ancestral domain" Archived March 6, 2016, at the Wayback Machine . Scribd. Retrieved on August 14, 2011.
  34. ↑ Orejas, Tonette (November 27, 2009). "It’s official: Pinatubo is now owned by Aetas" Archived November 18, 2011, at the Wayback Machine . PIPLinks (originally from Philippine Daily Inquirer ). Retrieved on August 14, 2011.
  35. 1 2 3 Valdez, Katrina Mennen A. (January 14, 2010). "Aetas to receive title to domain at Mt. Pinatubo" Archived April 15, 2013, at archive.today . Preda Foundation. Retrieved on August 14, 2011.
  36. ↑ Dominico C. Moneva (March 18, 2006). "Speak out: Magsaysay's death". SunStar Cebu. Archived from the original on May 17, 2008. Retrieved March 21, 2008.
  37. ↑ Enriquez, Marge (January 3, 2018). "Design duo tapped to build 'city of the future'". Philippine Daily Inquirer. Archived from the original on December 1, 2020. Retrieved March 9, 2018.
  38. ↑ "Trekking-Mt-Pinatubo". Philippine Daily Inquirer. May 29, 2010. Archived from the original on November 14, 2012. Retrieved June 13, 2012.

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Plinian eruptions or Vesuvian eruptions are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in 79 AD, which destroyed the ancient Roman cities of Herculaneum and Pompeii. The eruption was described in a letter written by Pliny the Younger, after the death of his uncle Pliny the Elder.

<span class="mw-page-title-main">Eruption column</span> A cloud of hot ash and volcanic gases emitted during an explosive volcanic eruption

An eruption column or eruption plume is a cloud of super-heated ash and tephra suspended in gases emitted during an explosive volcanic eruption. The volcanic materials form a vertical column or plume that may rise many kilometers into the air above the vent of the volcano. In the most explosive eruptions, the eruption column may rise over 40 km (25 mi), penetrating the stratosphere. Stratospheric injection of aerosols by volcanoes is a major cause of short-term climate change.

<span class="mw-page-title-main">Taal Volcano</span> Volcano in the Philippines

Taal Volcano is a large caldera filled by Taal Lake in the Philippines. Located in the province of Batangas about 50 kilometers (31 mi) south of Manila, the volcano is the second most active volcano in the country with 38 recorded historical eruptions, all of which were concentrated on Volcano Island, near the middle of Taal Lake. The caldera was formed by prehistoric eruptions between 140,000 and 5,380 BP.

<span class="mw-page-title-main">Mount Bulusan</span> Volcano in the Philippines

Mount Bulusan, also known as Bulusan Volcano, is a stratovolcano on the island of Luzon in the Philippines. Located in the province of Sorsogon in the Bicol Region, it is 70 kilometres (43 mi) southeast of Mayon Volcano and approximately 390 kilometres (240 mi) southeast of Manila. Bulusan is one of the active volcanoes in the Philippines.

<span class="mw-page-title-main">Kanlaon</span> Active volcano in the Philippines

Kanlaon, also known as Mount Kanlaon and Kanlaon Volcano, is an active andesitic stratovolcano and the highest mountain on the island of Negros in the Philippines, as well as the highest peak in the Visayas, with an elevation of 2,465 m (8,087 ft) above sea level. Mount Kanlaon ranks as the 42nd-highest peak of an island in the world.

<span class="mw-page-title-main">Cascade Volcanoes</span> Chain of stratovolcanoes in western North America

The Cascade Volcanoes are a number of volcanoes in a volcanic arc in western North America, extending from southwestern British Columbia through Washington and Oregon to Northern California, a distance of well over 700 miles (1,100 km). The arc formed due to subduction along the Cascadia subduction zone. Although taking its name from the Cascade Range, this term is a geologic grouping rather than a geographic one, and the Cascade Volcanoes extend north into the Coast Mountains, past the Fraser River which is the northward limit of the Cascade Range proper.

<span class="mw-page-title-main">Operation Fiery Vigil</span> Military operation

Operation Fiery Vigil was the emergency evacuation of all non-essential military and U.S. Department of Defense civilian personnel and their dependents from Clark Air Base and U.S. Naval Base Subic Bay during the June 1991 eruption of Mount Pinatubo in the Republic of the Philippines.

<span class="mw-page-title-main">Phreatomagmatic eruption</span> Volcanic eruption involving both steam and magma

Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions contain juvenile (magmatic) clasts. It is common for a large explosive eruption to have magmatic and phreatomagmatic components.

<span class="mw-page-title-main">Mount Natib</span> Dormant startovolcano in Bataan, Philippines

Mount Natib is a dormant stratovolcano and caldera complex in the Zambales Mountains on western Luzon Island of the Philippines. Occupying the northern portion of the Bataan Peninsula, the mountain and adjacent surrounding is a protected area first declared as the Bataan National Park in 1945.

<span class="mw-page-title-main">Mount Mariveles</span> Stratovolcano in Bataan, Philippines

Mount Mariveles is a dormant stratovolcano and the highest point in the province of Bataan in the Philippines. Mariveles and the adjacent Mount Natib comprise 80.9 percent of the total land area of the province. The mountain and adjacent cones lie opposite the city of Manila across Manila Bay, providing a beautiful setting for the sunsets seen from the city.

<span class="mw-page-title-main">Lake Pinatubo</span> Volcanic lake in Zambales, Philippines

Lake Pinatubo is the summit crater lake of Mount Pinatubo formed after its climactic eruption on June 15, 1991. The lake is located in the Zambales Mountains, in Botolan, Zambales, near the boundaries of Pampanga and Tarlac provinces in the Philippines. It is about 90 km (56 mi) northwest of the capital city of Manila. While one paper by researchers from Japan suggested a depth of 600 m (2,000 ft), more detailed research suggests that 95–115 m (312–377 ft) is more accurate.

<span class="mw-page-title-main">1991 eruption of Mount Pinatubo</span> Volcanic eruption in the Philippines

The 1991 eruption of Mount Pinatubo in the Philippines' Luzon Volcanic Arc was the second-largest volcanic eruption of the 20th century, behind only the 1912 eruption of Novarupta in Alaska. Eruptive activity began on April 2 as a series of phreatic explosions from a fissure that opened on the north side of Mount Pinatubo. Seismographs were set up and began monitoring the volcano for earthquakes. In late May, the number of seismic events under the volcano fluctuated from day-to-day. Beginning June 6, a swarm of progressively shallower earthquakes accompanied by inflationary tilt on the upper east flank of the mountain, culminated in the extrusion of a small lava dome.

References

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