Taal Volcano - WikiHQ

Taal Volcano (; ), also known as Taal Caldera, is a large caldera filled by Taal Lake in the Philippines. Located in the province of Batangas about south of Manila, the volcano is the second most active volcano in the country, with 39 recorded historical eruptions, all concentrated on Volcano Island, near the middle of Taal Lake. The caldera was formed by prehistoric eruptions between less than 670,000 and less than 6,000 years ago. The cones Batulao, Macolod, and Sungay are remnants of the early pre-caldera Taal system, with Batulao being the earliest known cone.

Taal Volcano has had several violent eruptions in the past, causing deaths on the island and the populated areas surrounding the lake, with an overall recorded death toll of about 6,000. Because of its proximity to populated areas and its eruptive history, the volcano was designated a Decade Volcano, worthy of close study to prevent future natural disasters. The site was declared National Geological Monument in 1998 and a national park in 2018.

Etymology

Taal Volcano was known as Pulo, Bombou or Bombon in the 1800s.

The municipality of Taal and the Taa-lan River (now known as Pansipit River) were named after the Taa-lan tree, which grows along the river. The tree also grew along the shore of Bombon Lake (now known as Taal Lake). The Taa-lan River was a narrow channel that connects the present-day Taal Lake and Balayan Bay to each other.

Taal is a Tagalog word in the Batangueño dialect that means true, genuine, and pure.

Geography

Taal Volcano is part of a chain of volcanoes lining the western edge of the island of Luzon. They were formed by the subduction of the Eurasian Plate underneath the Philippine Mobile Belt. Taal Lake lies within a caldera formed by explosive eruptions between less than 670 (Sampaga Formation) and less than 3 ka to 1000CE (Buco Formation). Each of these eruptions created extensive ignimbrite deposits reaching as far away as present-day Manila.

Taal Volcano is primarily located in the province of Batangas however, the northern caldera rim and the northern segment of its massive ignimbrite shield is located on Tagaytay which is in Cavite. The northern half of Volcano Island falls under the jurisdiction of the lake shore town of Talisay, and the southern half in San Nicolas. The other communities that encircle Taal Lake include the cities of Tanauan and Lipa, and the municipalities of Talisay, Laurel, Agoncillo, Santa Teresita, San Nicolas, Alitagtag, Cuenca, Balete, and Mataasnakahoy.

Surrounding the caldera is a large ignimbrite shield which extends in all directions. It is composed of the ignimbrites and other tephra deposits from prehistoric events. Since the formation of the caldera, subsequent eruptions have created a volcanic island within the caldera, known as Volcano Island. This island covers an area of about with the center of the island occupied by the Main Crater with a single crater lake formed from the 1911 eruption. The island is a resurgent dome consisting of overlapping cones and craters, of which forty-seven have been identified. Twenty six of these are tuff cones, five are cinder cones, and four are maars.

Permanent settlement on the island is prohibited by the Philippine Institute of Volcanology and Seismology (PHIVOLCS), declaring the whole Volcano Island as a high-risk area and a Permanent Danger Zone (PDZ). Despite the warnings, some appear to continue to reside on the island, mainly caretakers of fish cages.

Eruptive history

Prehistoric eruptions

The prehistoric eruptions of Taal were either large caldera forming events or minor eruptions similar to what is observed today. The major eruptions helped create the present Taal Lake, with a large eruption termed "The Pasong Fluidal Juvenile Bomb-Rich Ignimbrite Formation" ejecting of material, shaping the immediate landscape with pyroclastic flows and thick ash deposits across southern Luzon. Prehistoric eruptions left significant deposits of pumice and pyroclastic material across southern Luzon, with thicknesses up to in some areas, impacting vast regions. All major eruption deposits show evidence of plagioclase, pyroxene and magnetite fractionation, although magma evolution for the youngest three of the several eruption units was dominated by magma mixing. Over time, major eruption-units have been becoming more mafic from 63 wt.% SiO2 for the Alitagtag Formation to 58 wt.% SiO2 for the Buco Formation.

Comparing Taal's prehistoric "major" eruption volumes to better studied calderas, the DRE of the Buco eruption may compare to the 41 ka eruption of Irosin caldera which produced a caldera. The Alitagtag eruption, being of similar volume to the 1425 eruption of Kuwae caldera in Vanuatu which may have formed a caldera. The Indang eruption has a dense rock eruptive volume equivalent to that of the eruption of Mt. Mazama around 7,700 years ago, which formed a caldera. The Pasong eruption produced DRE more material than the Akahoya eruption that formed Kikai Caldera 7.3 ka. An estimated size for the Pasong caldera may have been larger than .

The Taal Group

The Taal Group denotes the pre-historic pyroclastic sequence of the Taal Caldera Volcano. It has ten named formations and three unofficial units. Each formation consists of one eruption unit, which is separated from the surrounding formations by a paleosoil or modified deposits. Informal 'units' consist of a bundle of multiple narrow layers containing many ancient soils without the distinctiveness needed for correlation into a formation. and likely represent a phase of more frequent, smaller-scale eruptions similar to the relatively small eruptions that occur historically. thumb|The now-dormant Binintiang Malaki (Giant Leg) cone was the center of the 1707 and 1715 eruptions.

Between 1707 and 1731, the center of volcanic activity shifted from the Main Crater to other parts of Volcano Island. The eruptions of 1707 and 1715 occurred in Binintiang Malaki (Giant Leg) crater, the cinder cone visible from Tagaytay Ridge, and was accompanied by thunder and lightning. Minor eruptions also occurred in Binintiang Munti crater on the westernmost tip of the island in 1709 and 1729. A more violent event happened on September 24, 1716, blowing out the entire southeastern portion of the crater of Calauit, opposite Mount Macolod. Father Manuel de Arce noted that the 1716 eruption "killed all the fishes...as if they had been cooked, since the water had been heated to a degree that it appeared to have been taken from a boiling caldron". The 1731 eruption off Pira-Piraso, the eastern tip of the island, created a new island.

In Manila, in the early hours of January 30, people were awakened by what they at first perceived as loud thunder. The illusion was heightened when lightning illuminated the southern skies. A huge, fan-shaped cloud of what looked like black smoke ascended to great heights, crisscrossed with a brilliant display of volcanic lightning. This cloud finally shot up in the air, spread, then dissipated, marking the culmination of the eruption, at about 2:30 am. which travelled several kilometers across Lake Taal, devastating villages on the lake shore and killing about a hundred people.

One American geologist, who had witnessed an atomic bomb explosion as a soldier, visited the volcano shortly after the 1965 eruption and recognised "base surge" (now called pyroclastic surge) as a process in volcanic eruption.

Precursory signs were not interpreted correctly until after the eruption; the population of the island was evacuated only after the onset of the eruption.

After nine months of repose, Taal reactivated on July 5, 1966, with another phreatomagmatic eruption from Mount Tabaro, followed by another similar eruption on August 16, 1967. The Strombolian eruptions, which started five months after on January 31, 1968, produced the first historical lava fountaining witnessed from Taal. Another Strombolian eruption followed a year later on October 29, 1969. The massive flows from the two eruptions eventually covered the bay created by the 1965 eruption, reaching the shore of Lake Taal. The last major activities on the volcano during this period were the phreatic eruptions of 1976 and 1977.

2008

On August 28, the PHIVOLCS notified the public and authorities that the Taal seismic network recorded 10 volcanic earthquakes from 05:30 to 15:00.

thumb|Taal Volcano provides a picturesque view from [[Tagaytay.]]

2010

On June 8, the PHIVOLCS raised the volcano status to Alert Level 2 (scale is 0–5, 0 referring to No Alert status), which indicates the volcano is undergoing magmatic intrusion, a precursor to an eruption. PHIVOLCS reminded the general public that the Main Crater was off-limits due to the possibility of hazardous steam-driven explosions and build-up of toxic gases. Areas with hot ground and steam emissions, such as portions of the Daang Kastila Trail, are considered hazardous. From May 11–24, Main Crater Lake's temperature increased by . The composition of Main Crater Lake water has shown above normal values of MgCl, SO4Cl, and Total Dissolved Solids. There has been ground steaming, accompanied by hissing sounds, on the northern and northeast sides of the main crater. On April 26, the volcanic seismicity was reported to have had increased.

2011

From April 9 to July 5, the alert level on Taal Volcano was raised from 1 to 2 because of the increased seismicity of Volcano Island. Frequency peaked at about 115 tremors on May 30 with a maximum intensity of IV, accompanied by rumbling sounds. Magma was intruding towards the surface, as indicated by continuing high rates of CO2 emissions in the Main Crater Lake and sustained seismic activity. Field measurements on May 24 showed that lake temperatures had increased slightly, pH values were slightly more acidic, and water levels were higher. A deformation survey conducted around Volcano Island from April 26 to May 3 showed that the volcano edifice had inflated slightly relative to the April 5–11 survey.

2020 to 2026 activity and eruption

2020

thumb|The January 12, 2020, eruption

The volcano erupted on the afternoon of January 12, with the alert level of the Philippine Institute of Volcanology and Seismology (PHIVOLCS) escalating from Alert Level 2 to Alert Level 4. It was a Plinian eruption from the main crater on Volcano Island. The eruption spewed bomb to lapilli sized scoria fragments along with ash to Calabarzon, Metro Manila, some parts of Central Luzon, and Pangasinan, in the Ilocos Region, which cancelled classes, work schedules, and flights. The rain of scoria and ash along with and volcanic thunderstorms were reported, and forced evacuations were made from the island. There were also warnings of a possible volcanic tsunami. The volcano produced volcanic lightning above its crater with ash clouds. The eruption progressed into a magmatic eruption, characterized by a lava fountain with thunder and lightning. By January 26, 2020, PHIVOLCS observed an inconsistent, but decreasing volcanic activity in Taal, prompting the agency to downgrade its warning to Alert Level 3. On February 14, PHIVOLCS downgraded the volcano's warning to Alert Level 2, due to consistent decreased volcanic activity. A total of 39 people died in the eruption, mostly because they refused to leave their homes or suffered health-related problems during the evacuation.

2021

thumb|Recorded [[IP camera|IP cam of the eruption taken on July 1, 2021, by PHIVOLCS]]

In February, residents from Taal Volcano Island were preemptively evacuated due to the volcano's increasing activity. On March 9, 2021, PHIVOLCS raised the alert level from 1 to 2. In June, the volcano's emission of sulfur dioxide gas caused vog to appear over nearby provinces, and even Metro Manila. On July 1, the volcano erupted at around 3:16 p.m, and the alert level was raised from Alert Level 2 to Level 3. 19 weak phreatomagmatic bursts were recorded until July 9.

On July 23, PHIVOLCS lowered the alert level status from Alert Level 3 to Level 2.

2022

Between January 29 and 30, the volcano had nine phreatomagmatic bursts on its main crater. On March 26, PHIVOLCS raised the volcano's alert level status to Alert Level 3 due to a short lived-phreatomagmatic eruption with the evacuation of around 1,100 residents around the area and surrounding towns. Two phreatomagmatic events were recorded in which it emitted toxic plumes of and . Locals have then reported an explosion near the crater around 1:00 PM (Philippine Time) with subsequent spurs of ashes around the lake. High level toxic emissions have been recorded as well as 14 volcanic earthquakes and 10 volcanic tremors within the day. The next day on March 27, volcanic activities were relatively tranquil with almost no recorded earthquakes although sulfur dioxide emission still measured at 1,140 tons. The National Disaster Risk Reduction and Management Council (NDRRMC) estimated that some 3,850 individuals were displaced on Monday, March 28. On April 9, PHIVOLCS downgraded again the alert level status from Level 3 to Level 2. It was then downgraded further to Alert Level 1 after around three months on July 11.

On August 3, PHILVOLCS recorded a low-level unrest of the volcano with the increase of sulfur dioxide (SO2) emission. Abnormal spike of sulfur in the atmosphere was measured up to 12,125 tons that day. For comparison, daily and usual sulfur dioxide emission was measured up to 4,952 tons since July 15. Volcanic smog, or vog, and toxic gases were largely observed in Batangas and surrounding towns since August 2.

2023

In June, sulfur dioxide levels around the volcano massively increased, causing a vog that forced the suspension of classes in Laurel and Talisay, as well as in parts of Agoncillo. On June 29, PHIVOLCS recorded a phreatic burst that lasted for one minute and eight seconds. In mid September, the volcano again released vog that also forced the suspension of classes not only in Batangas but in neighboring cities and provinces as well. Vog was released at an average of per day.

2024

In June, five volcanic earthquakes were reported, causing a series of phreatic eruptions in a 24-hour period, releasing of sulfur dioxide into the atmosphere. Taal Volcano was under Alert Level 1 during September when several minor eruptions occurred.

On October 2, another series of minor phreatic eruptions were reported, lasting between two or six minutes. The volcano then underwent a phreatomagmatic eruption, emitting a plume that reached a height of , though the Alert Level 1 status remains unchanged. Another minor phreatomagmatic eruption occurred on October 5 and October 10.

Two more phreatic eruptions were reported on October 16.

On December 3, a minor phreatomagmatic eruption was reported at 5:58 am, producing a grayish plume reaching .

2025

A phreatic eruption occurred on May 29, followed by a minor phreatomagmatic eruption on July 17. Another phreatic eruption occurred on September 11, while two minor eruptions occurred on October 1. A phreatic eruption occurred on October 13, followed by a minor phreatomagmatic eruption on October 20. Three minor eruptions occurred on October 26, while minor phreatomagmatic eruptions occurred on November 12 and November 23. Two minor eruptions occurred on December 4. Another minor phreatomagmatic eruption occurred on December 26. It produced ash jets and plumes that soon rose up to 600 meters before drifting to the southwest.

2026

A small phreatomagmatic eruption occurred in Jan 9, 2026.

Wildfires

On May 6, 2024, Batangas governor Hermilando Mandanas declared Volcano Island a "no man's land" due to series of wildfire devastation on its southwest tip on May 2, near the Binintiang Munti observation station.

A grassfire broke out on April 2, 2025. It was eventually put out 21 hours later.

Activity monitoring

thumb|A solar-powered remote monitoring station located at Taal Volcano island

thumb|Taal Volcano Observatory’s Data Receiving Center acquires real-time digital multi-parameter volcano monitoring data streams from remote observation stations installed around the Volcano Island and Taal Caldera.

thumb|Taal Volcano Monitoring Network map

Alert levels

PHIVOLCS maintains a distinct Alert Level system for six volcanoes in the Philippines, including Taal Volcano. There are six levels in the system, numbered 0 to 5.

{| class="wikitable" style="text-align:left; font-size:95%;"

|+ Taal Volcano Alert Level Scheme However, with some eruptions, there is no reported increase in the lake's temperature.

Development of new or reactivation of old thermal areas like fumaroles, geysers or mudpots.
Ground inflation or ground fissuring.
Increase in temperature of ground probe holes on monitoring stations.
Strong sulfuric odor or irritating fumes similar to rotten eggs.
Fish dieoffs and the drying up of vegetation.

Other possible precursors

Volcanologists measuring the concentration of radon gas in the soil on Volcano Island measured an anomalous increase of radon concentration by a factor of six in October 1994. This increase was followed 22 days later by the magnitude 7.1 Mindoro earthquake on November 15, centered about south of Taal, off the coast of Luzon. A typhoon had passed through the area a few days before the radon spike was measured, but when Typhoon Angela, one of the most powerful to strike the area in ten years, crossed Luzon on almost the same track a year later, no radon spike was measured. Typhoons, therefore, were ruled out as the cause, and strong evidence suggests that the radon originated in the stress accumulation before the earthquake.

References

External links

Taal Volcano Eruptions 1572–1911 from RWTH Aachen University Web Site