Mayon
Mayon, also known as Mount Mayon and Mayon Volcano, is an active stratovolcano in the province of Albay in Bicol, Philippines. A popular tourist destination, it is renowned for its "perfect cone" owing to its symmetric conical shape, and is regarded as sacred in Philippine mythology.
The volcano with its surrounding landscape was declared a national park on July 20, 1938, the first in the nation. It was reclassified as a natural park and renamed the Mayon Volcano Natural Park in 2000. It is the centerpiece of the Albay Biosphere Reserve as declared by UNESCO in 2016, and is currently being nominated as a World Heritage Site.
Mayon is the most active volcano in the Philippines, and its activity is regularly monitored by the Philippine Institute of Volcanology and Seismology from their provincial headquarters on Ligñon Hill, about from the summit.
Geography
Mayon is the main landmark and highest point of the province of Albay and the whole Bicol Region in the Philippines, rising from the shores of Albay Gulf about away. The volcano is geographically shared by the eight cities and municipalities of Legazpi, Daraga, Camalig, Guinobatan, Ligao, Tabaco, Malilipot, and Santo Domingo, which divide the cone like slices of a pie when viewing a map of their political boundaries.Geology
Mayon is a classic stratovolcano with a small central summit crater. It is one of the world's most symmetrical volcanic cones.The concave profile, a hyperbolic sine curve of the volcano is due to the balance between erosion and eruption, defined by the angle of repose of ash. The steepest upper slopes of the volcano reach an average slope gradient of 75%, while the lower foot slope is only an average of 3%. The volcanic crater is about 250 m in diameter. At least 85 lava flows have been identified, and consist mainly of lava augite-hypersthene-andesite, generally fed from the crater. Pyroclastic flows, characterized as a St. Vincent nuee' ardente, leave behind block and ash deposits, and breadcrust bombs in an ash and lapilli matrix. The farthest flow reached 8.5 km along Fidel Surtida, Santo Domingo. Mayon lahars were formed by rainstorms during eruptions, or by torrential rain afterwards. Averaging 230 m in height and 710 m in diameter, 7 cinder cones are found on the southern and southwestern lower slopes. Composed of olivine-augite basalt, these cones have an angle of repose of 34%, with Ligñon Hill as an example.
Like other volcanoes around the Pacific Ocean, Mayon is a part of the Pacific Ring of Fire. It is on the southeast side of Luzon. The Bicol Arc is one of 7 oceanic trench subduction zones defining the Philippine Mobile Belt. Volcanism in the Bicol Arc is related to the westward subduction of the Philippine Plate along the Philippine Trench. The 12 active and inactive volcanoes within the arc include the Mayon Volcano, Mount Bulusan, Mount Isarog, Mount Iriga, Malinao Volcano, and Mount Masaraga. In general, these are calc-alkali basalts, basaltic andesites, and andesites.
In August 2021, soils from Mayon have been found containing bacterial species with potential antibiotic and anti-cancer properties.
Recorded eruptions
Mayon is the most active volcano in the Philippines, erupting over 52 times in the past 500 years. Historical observations accounted its first eruption in 1616. The first eruption for which an extended account exists was the six-day event of July 20, 1766.1814 eruption
Its most destructive recorded eruption occurred on February 1. Lava flowed but less than the 1766 eruption. The volcano belched dark ash and eventually bombarded the town of Cagsawa with tephra that buried it. Trees burned, and rivers were certainly damaged. Proximate areas were also devastated by the eruption, with ash accumulating to in depth. In Cagsawa town, about 1,200 locals perished in what is considered to be the most lethal eruption in Mayon's history according to PHIVOLCS. The 1814 eruption is believed to have contributed to the accumulation of atmospheric ash together with the catastrophic 1815 eruption of other volcanoes like Indonesia's Mount Tambora, leading to the Year Without a Summer in 1816.1881–1882 eruption
From July 6, 1881, until approximately August 1882, Mayon underwent a strong eruption. Samuel Kneeland, a naturalist, professor and geologist, personally observed the volcanic activity on Christmas Day, 1881, about five months after the start of the activity:
At the date of my visit, the volcano had poured out, for five months continuously, a stream of lava on the Legaspi side from the very summit. The viscid mass bubbled quietly but grandly, and overran the border of the crater, descending several hundred feet in a glowing wave, like red-hot iron. Gradually, fading as the upper surface cooled, it changed to a thousand sparkling rills among the crevices, and, as it passed beyond the line of complete vision behind the woods near the base, the fires twinkled like stars or the scintillations of a dying conflagration. More than half of the mountain height was thus illuminated.
1897 eruption
Mayon's longest uninterrupted eruption occurred on June 23, and lasted for seven days. Lava once again flowed down to towns eastward, the village of Bacacay was buried beneath the lava. In Santo Domingo 100 people were killed by steam and falling debris or hot rocks. Other villages like San Roque, Santa Misericordia and Santo Niño became deathtraps. Ash was carried in black clouds as far as from the catastrophic event, which killed more than 400 people.1984 and 1993 eruptions
No casualties were recorded from the 1984 eruption after more than 73,000 people were evacuated from the danger zones as recommended by PHIVOLCS scientists. But in 1993, pyroclastic flows killed 79 people, mainly farmers, during the eruption that also forced 50,000 residents evacuated, according to the Albay provincial government.1999 eruption
Mayon began its increasing activity in May, with hazard status associated raised to Alert Level 1. On June 22, Mayon emitted an ash column that rose to approximately 10 km above the vent; the status was later raised to Alert Level 2. The emission was recorded by the seismic network of the Philippine Institute of Volcanology and Seismology as an explosion that lasted for 10 minutes. No volcanic earthquakes nor other visible signs of abnormal activity were observed before the explosion.2000 eruptions
Mayon had experienced continuous emissions since 1999 and followed by a series of eruptions in the next two consecutive years.On January 5, a 5-km-high ash column was produced by an explosion. Growth of summit-crater dome and intensifying eruptions later signaled evacuations.
Past emissions had led to the growth of the lava dome beginning on February 12. On February 23, series of eruptions began. PHIVOLCS then recommended evacuation even beyond the permanent danger zone. On February 24, PHIVOLCS raised its status to the highest, Alert Level 5, with at least eight towns and one city warned of possible explosions with ash and lava flows, and several thousands forced to evacuate even outside identified danger zones. The most violent eruptions were occurred from February 28 to March 1, and since then, declining activity was observed until April.
The National Disaster Risk Reduction and Management Council reported that the 2000 eruption displaced 14,114 families and damaged at least ₱89-million worth of property and crops.
2001 eruption
The NDCC reported that another eruption in July affected 11,529 families and damaged at least ₱48-million worth of property and crops.2006 eruptions
Mayon's 48th modern-era eruption occurred on July 13, followed by quiet effusion of lava that started on July 14. Nearly 40,000 people were evacuated from the danger zone on the southeast flank of the volcano.After an ash explosion on September 1, a general decline in the overall activity of Mayon was established. The decrease in key parameters such as seismicity, sulfur dioxide emission rates and ground inflation all indicated a waning condition. The slowdown in the eruptive activity was also evident from the decrease in intensity of crater glow and the diminishing volume of lava extruded from the summit. PHILVOLCS Alert Level 4 was lowered to Level 3 on September 11; to Level 2 on October 3; and to Level 1 on October 25.
2008 eruption
On August 10, a small summit explosion ejected ash above the summit, which drifted east-northeast. In the weeks prior to the eruption, a visible glow increased within the crater and increased seismicity.2009–2010 eruptions
On July 10, 2009, PHIVOLCS raised the status from Alert Level 1 to Alert Level 2 because the number of recorded low frequency volcanic earthquakes rose to the same level as those prior to the 2008 phreatic explosion.At 5:32 a.m. on October 28, a minor ash explosion lasting for about one minute occurred in the summit crater. A brown ash column rose about above the crater and drifted northeast. In the prior 24 hours, 13 volcanic earthquakes were recorded. Steam emission was at moderate level, creeping downslope toward the southwest. PHIVOLCS maintained the Alert Status at Level 2, but later warned that with the approach of tropical cyclone international codename Mirinae, the danger of lahars and possible crater wall collapse would greatly increase and all specified precautions should be taken.
After dawn, field investigation showed ashfall had drifted southwest of the volcano. In the 24-hour period, the seismic network recorded 20 volcanic earthquakes. Alert Status was kept at Level 2.
At 8 pm on December 14, after 83 volcanic quakes in the preceding 24 hours and increased sulfur dioxide emissions, PHIVOLCS raised the Alert status to Level 3.
Early in the morning of December 15, a moderate ash explosion occurred at the summit crater and "quiet extrusion of lava" resulted in flows down to about from the summit. By evening, Albay Province authorities evacuated about 20,000 residents out of the danger zone and into local evacuation centres. About 50,000 people live within the zone.
On December 17, five ash ejections occurred, with one reaching above the summit. Sulfur dioxide emission increased to 2,758 tonnes per 24 hours, lava flows reached down to below the summit, and incandescent fragments from the lava pile continuously rolling down Bonga Gully reached a distance of 3–4 km below the summit. By midday, a total of 33,833 people from 7,103 families had been evacuated, 72 percent of the total number of people that needed to be evacuated, according to Albay Governor Joey Salceda.
On December 20, PHIVOLCS raised Mayon's status level to alert level 4 because of an increasing lava flow in the southern portion of the volcano and an increase in sulfur dioxide emission to 750 tonnes per day. Almost 460 earthquakes in the volcano were monitored. In the border of the danger zone, rumbling sounds like thunder were heard. Over 9,000 families were evacuated by the Philippine government from the base of the volcano. No civilian was permitted within the 8 km danger zone, which was cordoned off by the Philippine military who actively patrolled to enforce the "no-go" rule and to ensure no damage or loss of property of those evacuated.
Alert level 4 was maintained as the volcano remained restive through December, prompting affected residents to spend Christmas and the New Year in evacuation centers. On December 25, sulfur dioxide emissions peaked at 8,993 tons per day. On December 28, PHIVOLCS director Renato Solidum commented on the status of the volcano, "You might think it is taking a break but the volcano is still swelling." On the next day December 29, a civil aviation warning for the airspace near the summit was included in the volcano bulletins. The ejected volcanic material since the start of the eruption was estimated to have been between 20 million to 23 million cubic meters of rocks and volcanic debris, compared to 50 million to 60 million cubic meters in past eruptions.
On January 2, 2010, PHIVOLCS lowered the alert level of the volcano from level 4 to level 3, citing decreasing activity observed over the prior four days. The state agency noted the absence of ash ejections and relative weakness of steam emissions and the gradual decrease in sulfur dioxide emissions from a maximum of 8,993 tonnes per day to 2,621 tonnes per day. 7,218 families within the 7–8 km danger zones returned to their homes, while 2,728 families residing in the 4–6 km danger zone remained in the evacuation centers pending a decision to further lower the alert level.
On January 13, PHIVOLCS reduced the Alert Level from 3 to 2 due to a further reduction in the likelihood of hazardous eruption.