Mayon Volcano, also known as
Mount Mayon, is an
active volcano in the
province of
Albay, on the island of
Luzon in the
Philippines. Renowned as the "perfect cone" because of its almost
symmetric conical shape, Mayon forms the northern boundary of
Legazpi City, the largest city in terms of population in the
Bicol Region. The mountain is a
national park and a
protected landscape in the country proclaimed as as
Mayon Volcano Natural Park in the year 2000.
[3]
Local
folklore refers to the volcano as Bulkang Magayon (
Bikol: 'Beautiful Volcano'), after the legendary heroine
Daragang
Mayon Volcano is the main landmark of
Albay Province, Philippines, rising 2,462 metres (8,077 ft) from the shores of the
Gulf of Albay about 10 kilometres (6.2 mi) away.
[5][6] The volcano is geographically shared by the cities and municipalities of
Legazpi City,
Daraga,
Camalig,
Guinobatan,
Ligao City,
Tabaco City,
Malilipot, and
Santo Domingo (clockwise from Legazpi) which divide the cone like slices of a pie when viewed from above.
[] Geomorphology
Mayon is a classic
stratovolcano type of
volcano capped by a small central summit
crater. The cone is considered to be the world's most perfectly-formed volcano for its symmetry,
[6] which was formed through layers of
pyroclastic and
lava flows from past eruptions and
erosion. The upper slopes of the
basaltic-
andesitic volcano are steep averaging 35–40 degrees.
Like other volcanoes located around the Pacific Ocean, Mayon is part of the
Pacific Ring of Fire. It is located on the eastern side of
Luzon, near the
Philippine Trench which is the
convergent boundary where the
Philippine Sea Plate is driven under the
Philippine Mobile Belt. When a
continental plate or belt of continental fragments meets an
oceanic plate, the lighter continental material overrides the oceanic plate, forcing it down into the Earth's mantle.
Magma may be forced through weaknesses in the continental crust caused by the collision of the
tectonic plates. One such exit point is Mayon.
[] Recorded eruptions
Mayon is the most active
volcano in the Philippines having erupted over 48 times in the past 400 years.
[7] The first record of a major eruption was witnessed in February 1616 by Dutch explorer
Joris van Spilbergen who recorded it on his log in his
circumnavigation trip around the world.
[8]
An old photograph of the
Cagsawa ruins with the facade still standing. The church was largely destroyed during the 1814 eruption of Mayon.
The most destructive eruption of Mayon occurred on February 1, 1814.
Lava flowed but not as much compared to the 1766 eruption. Instead, the
volcano was belching dark ash and eventually bombarding the town with
tephra that buried the town of
Cagsawa.
Trees were burned; rivers were certainly damaged. Proximate areas were
also devastated by the eruption with ash accumulating to 9 m (30 ft) in
depth. 2,200 Albay locals perished in what is considered to be the most
lethal eruption in Mayon's history.
[6]
Estimates by PHIVOLCS and list the casualties at about 1200. The
eruption is believed to have contributed to the accumulation of
atmospheric ash,
[citation needed] capped off by the catastrophic eruption of
Mount Tambora in 1815, that led to the
Year Without a Summer in 1816.
Mount Mayon in eruption on July 21, 1928.
Mayon Volcano's longest uninterrupted eruption occurred on June 23,
1897 which lasted for seven days of raining fire. Lava once again
flowed down to civilization. Seven miles eastward, the village of
Bacacay was buried 15 m (49 ft) beneath the lava. In
Libon
100 people were declared dead—incinerated by steam and falling debris
or hot rocks. Other villages like San Roque, Misericordia and Santo
Niño became deathtraps. Ash was carried in black clouds as far as
160 km (100 mi) from the catastrophic event, which killed more than 400
people.
[6]
Samuel Kneeland, a professor and a geologist had observed the volcanic activity five months before the eruption:
At night the scene was truly magnificent and unique. At the date
of my visit the volcano had poured out...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 scintillions of a dying conflagration. More than half of the
mountain height was thus illuminated.[9]
Mayon Volcano on September 23, 1984
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.
[10] But in 1993,
pyroclastic flows killed 77 people, mainly farmers, during the eruption.
Its 48th eruption was a quiet effusion of lava on July 14, 2006,
[11] which was aggravated when a
lahar caused by the rains of
Typhoon Durian
followed on November 30, 2006. The small activities from 2003 and 2004
are considered as precursors to the 2006 eruption. The small summit
explosion which occurred on August 10, 2008 is considered as part of
the ongoing activity since 2006.
[7] Starting in January 2011, the volcano is weakly erupting and may be building up to a larger hazardous eruption.
[edit] 2006 eruption
Mayon erupted again from July to October 2006, with no apparent loss of life during the actual eruption period.
- August 7, 2006: The Philippine government ordered the evacuation of
about 20,000 people living near the volcano, stating that an eruption
was feared soon.[12] Volcanologists have detected 21 low-frequency volcanic earthquakes since early Sunday morning.[13]
- August 8, 2006: The government expected to move some 34,276 people
to 31 state-run shelters and warned that the mountain could explode at
any time.[14][15]
Mayon Volcano in satellite image.
- August 9, 2006: Volcanologists warned that Mount Mayon could explode at any time but that the gravitational pull of a full moon
could provide the final push. A full moon coincided with at least three
of Mayon’s nearly 50 explosions over the last four centuries, including
the two most recent in 2000 and 2001. Nearly 40,000 people have been
moved from an 8 km (5 mi) danger zone on the southeast flank of the
volcano, which has been quaking and spitting plumes of ash since July.[16]
- August 10, 2006: Scientists in the Philippines renewed warnings of
a major explosion at the Mount Mayon volcano, describing a sudden
period of quiet as "ominous". A drop in gas emissions and earthquakes sparked fears that the crater had plugged itself, increasing the likelihood of an explosive eruption.[17]
- August 11, 2006: Scientists said ground surveys showed Mayon was
still "swollen" and registered a high number of volcanic earthquakes,
emitted large amounts of sulfur dioxide gas and continued to eject lava down its slope nearly four weeks after it came to life in a "quiet" eruption on July 14.[18]
Phivolcs maintained threat level at Alert Level 4 for the next month
because of the continued extrusion of lava, ash explosions, steam and
smoke plumes, seismic activity, and threat of further eruption.
- September 11, 2006 Phivolcs downgraded threat level to Alert Level
3. "After the ash explosion of September 1, a general decline in the
overall activity of Mayon has been established. The decrease in key
parameters such as seismicity, gas (Sulfur Dioxide) emission rates and
ground inflation all indicate a waning condition. The slowdown in the
eruptive activity is also evident from the decrease in intensity of
crater glow and the diminishing volume of lava being extruded from the
summit".[19]
- October 3, 2006 Phivolcs downgraded threat level to Alert Level 2.
"All monitored key parameters such as earthquake levels, ground
deformation and gas outputs further declined. In addition, lava
extrusion apparently ceased on October 1, 2006 as reported by Ligñon
Hill Observatory. The above observations indicate the absence of an
intruding new mass of magma."[20]
- October 25, 2006 Phivolcs downgraded threat level to Alert Level 1 (no hazardous eruption imminent).[21]
[] 2008 eruption
On August 10, 2008, a small summit explosion ejected ash 200 metres
(660 ft) above the summit, with the ash drifting east northeast. In the
weeks prior to the eruption,
[22] there was a visible glow within the crater and increased seismicity.
[23]
[] 2009–2010 eruption
On July 10, 2009,
PHIVOLCS
raised the status from Alert Level 1 (low level unrest) to Alert Level
2 (moderate unrest) because the number of recorded low frequency
volcanic earthquakes rose to the same level when a
phreatic explosion occurred last August 2008.
[24][25]
At 5:32 am Wednesday October 28, 2009, a minor ash explosion lasting
for about one minute occurred in the summit crater. A brown ash column
rose about 600 metres (2,000 ft) above the crater and drifted toward
the 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 will greatly increase and all specified precautions
should be taken.
[26]
At 1:58 am Wednesday November 11, 2009, a minor ash explosion
occurred at the summit crater lasting for about three minutes. This was
recorded by the seismic network as an explosion type earthquake with
rumbling sounds. Incandescent rock fragments at the upper slope were
observed in nearby barangays. Ash column was not observed because of
cloud cover. 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
indicating the current state of unrest could lead to more ash explosion
or eventually to hazardous magmatic eruption.
[27]
Mayon Volcano with
ash explosion at dawn on December 18, 2009
At 8 pm on Monday December 14, 2009, as a result of 83 volcanic quakes in the preceding 24 hours
[28] and increased sulphur dioxide emissions, Phivolcs raised the Alert status to Level 3.
[29]
Early in the morning of Tuesday December 15, 2009, a moderate ash
explosion occurred at the summit crater and "quiet extrusion of lava"
resulted in flows down to about 500 metres from the summit of Mayon.
[30]
By Tuesday night Albay Province authorities were reported to have moved
about 20,000 residents out of the eight kilometre danger zone and into
local evacuation centres. About 50,000 people were said to live within
the eight kilometer zone.
[31][32]
On December 17, 2009, there were five ash ejections with one
reaching 500 meters above the summit, sulphur dioxide emission
increased to 2,758 tonnes per 24 hours, lava flows reached down to 1500
metres below the summit, and incandescent fragments from the lava pile
continuously rolling down Bonga Gully reached a distance of 3 to 4 km
below the summit. By midday December 17, 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, Albay Governor Joey Salceda was
reported to have said.
[33]
On December 20, 2009, 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 sulphur dioxide emission to 750 tonnes
per day. As well, almost 460 earthquakes in the volcano were monitored
everyday. In the border of danger zone, rumbling sounds like thunder
were also heard. Over 9,000 families (44,394 people) were evacuated by
the Philippine government from the base of the volcano.
[34]
No civilian was permitted within the 8 kilometer danger zone, which has
been cordoned off by the Philippine military, who were actively
patrolling within the danger zone to enforce the "no-go" rule and to
ensure no damage or loss of property of those evacuated.
[35]
Mayon Volcano in eruption on December 29, 2009.
Alert level 4 was maintained as the volcano remained restive through
the month of December, prompting affected residents to spend Christmas
and the New Year in evacuation centers.
[36] On December 25, sulfur dioxide emissions peaked at 8,993 tons per day.
[37][38]
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."
[35] On the next day December 29, a civil aviation warning for the airspace near the summit was included in the volcano bulletins.
[39]
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.
[40]
On January 2, 2010, PHIVOLCS lowered the alert level of the volcano
from level 4 to level 3, citing decreasing activity observed in the
past four days.
[41]
The state agency noted the following observations as a trend of
decreasing activity: absence of ash ejections and relative weakness of
steam emissions, majority of earthquakes caused by rockfalls and
rolling fragments, and gradual decrease in sulfur dioxide emissions
from a maximum of 8,993 tons per day to 2,621 tons per day.
[38]
7,218 families within the seven-kilometer to eight-kilometer danger
zones were allowed to return to their homes, while 2,728 families who
live in the four-kilometer to six-kilometer danger zones would have to
stay in the evacuation centers pending the PHIVOLCS decision to further
lower the alert level.
[42]
On January 13, 2010, PHIVOLCS reduced the alert level from 3 to 2,
saying that this indicated a further reduction in the likelihood of
hazardous eruption.
[43]
[] Government response
Map showing major volcanoes of the Philippines
Albay governor Joey Salceda declared the disaster zone an 'open
city' area to encourage aid from external groups. Potential donors of
relief goods were not required to secure clearance from the Provincial
Disaster Coordinating Council, but were able to directly coordinate
with support groups at the local government level.
[44]
The restiveness of the volcano also stimulated the tourism industry
of the province. Up to 2,400 tourists per day have arrived in the area
since the volcano started erupting on December 14, filling local
hotels, compared to about a more modest average of 200 in the days
prior. However it was reported that some tourists lured by local
"guides" might be ignoring government warnings not to venture into the
8-kilometre (5.0 mi) danger zone. "It's a big problem. I think the
first violation of the zero casualty (record) will be a dead tourist,"
said Salceda.
[45]
Speaking about thrill-seekers finding their way in to the area,
Salceda warned, "At the moment of the eruption, the local guides will
have better chance of getting out. The hapless tourist will be left
behind."
[45]
[] International response
Following the declaration of alert level 3 for the volcano, the
United States issued an advisory cautioning its nationals from
traveling to Mayon. Canada and the United Kingdom also posted
advisories discouraging their nationals from visiting the volcano.
[46]
The United States government has committed $100,000 in financial aid
for the evacuees of Mayon Volcano. In cooperation with the Philippine
government the assistance will be delivered through the
Philippine National Red Cross and other NGOs by
USAID.
[47]
The Albay provincial government has ordered the local military to
add more checkpoints, place roadblocks and arrest tourists caught
traveling inside the eight-kilometer danger zone.
[48]
Power and water supply were cut off within the danger zone to further discourage residents from returning. The
Commission on Human Rights
has allowed the use of emergency measures and has given the authorities
clearance to forcibly evacuate residents who refuse to leave.
[49]
When the alert level around the volcano was lowered from alert level
4 to alert level 3 on January 2, 2010, the Albay provincial government
ordered a decampment of some 47,000 displaced residents from the
evacuation centers.
[50] Power and water supply in the danger zones were restored.
[36]
Military vehicles were used to transport the evacuees back to their
homes, while food supplies and temporary employment through the
Department of Social Welfare and Development (DSWD) were provided to the heads of each family.
[50][51] As of January 3, 2010, the
National Disaster Coordinating Council
reported the overall cost of humanitarian aid and other assistance
provided by the government and non-government organizations (NGOs) has
reached over 61 million pesos since the start of the eruption.
[52]
The United Nations
World Food Programme (UN-WFP) has delivered 20 tons of
high energy biscuits
to the evacuees to complement supplies provided by the DSWD, with more
to be allocated from emergency food stocks intended for relief from the
effects of the 2009 Pacific typhoon season.
[53]
When the alert level was downgraded to level 3 on January 2, 2010,
UN-WFP provided three days worth of food for evacuees returning to
their homes who will continue to receive supplies already set aside for
them.
[41]
[] Devastating lahars following eruptions and typhoons
The church tower is what remains of the
Cagsawa Church, which was buried by the 1814 eruption of Mayon Volcano. It withstood the damage done by
Typhoon Durian in 2006.
Following the eruption of 2006, on November 30 of that year, strong rainfall which accompanied
Typhoon Durian produced
lahars from the
volcanic ash
and boulders of the last eruption killing at least 1,266 people. The
precise figure may never be known since many people were buried under
the
mudslides.
[4] A large portion of the village of Padang (an outer suburb of
Legazpi City) was covered in mud up to the houses' roofs.
[54][55] Students from
Aquinas University in
Barangay
Rawis, also in Legazpi, were among those killed as mudslides engulfed
their dormitory. Central Legazpi escaped the mudslide but suffered from
severe flooding and power cuts.
Parts of the town of
Daraga
were also devastated, including the Cagsawa area, where the ruins from
the eruption of 1814 were partially buried once again. Large areas of
Guinobatan, Albay were destroyed, particularly Barangay Maipon.
Similar post-eruption lahar occurred in October 1766, months after
the July eruption of that year. The heavy rainfall also accompanying a
violent typhoon carried down disintegrated fragmental ejecta, burying
plantations and whole villages. In 1825, the event was repeated in
Cagsawa killing 1,500 people.
[56]
[] Monitoring Mayon
Mayon Volcano is the most active volcano in the Philippines, and its
activity is regularly monitored by PHIVOLCS from their provincial
headquarters on Lignon Hill, about 10 kilometres (6.2 mi) SSE from the
summit.
Three telemetric units are installed on Mayon's slopes, which send information to the seven
seismometers
in different locations around the volcano. These instruments relay data
to the Lignon Hill observatory and the PHIVOLCS central headquarters on
the
University of the Philippines Diliman campus.
PHIVOLCS also deploys electronic distance meters (EDMs), precise
leveling benchmarks, and portable fly spectrometers to monitor the
volcano's daily activity.
ayon Volcano is the main landmark of
Albay Province, Philippines, rising 2,462 metres (8,077 ft) from the shores of the
Gulf of Albay
