Филиппин Тау Жанұртының Сипаттамасы

Volcano in the Philippines

Taal Volcano (; ) is a large caldera filled by Taal Lake in the Philippines. The caldera was formed by prehistoric eruptions between 140,000 and 5,380 BP. 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 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.

Taal Volcano was known as 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.

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 140,000 and 5,380 BP. Taal Volcano and Lake are entirely located in the province of Batangas. 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. 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 families remain settled on the island, earning a living by fishing and farming crops in the rich volcanic soil. 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 consists of different 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.

On May 6, 2024, Hermilando Mandanas declared TVI which is under Alert Level 1 Low level unrest a "no man's land," due to series of wildfire devastation on the southwest tip of TVI on May 2, near the Binintiang Munti observation station.

There were 54 recorded eruptions at Taal between 1572 and 1977. The first recorded eruption occurred in 1572, the year Augustinian friars founded the town of Taal on the shores of the lake (on what is now San Nicolas, Batangas). In 1591, another mild eruption took place, producing great masses of smoke from the crater. From 1605 to 1611, the volcano displayed such great activity that Father Tomas de Abreu had a huge cross of anubing wood erected on the brink of the crater. 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.

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.

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.

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.

Alert Level 1 was raised on the volcano because of frequent volcanic activities since March. Based on the 24 hour monitoring of the Taal Volcano's seismic network, 57 volcanic earthquakes were observed from the morning of November 11 to the morning of November 12.

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 an eruption from the main crater on Volcano Island. The eruption spewed ashes to Calabarzon, Metro Manila, some parts of Central Luzon, and Pangasinan, in the Ilocos Region, which cancelled classes, work schedules, and flights. Ashfalls 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.

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. Five eruptions were recorded on July 7. On July 23, PHIVOLCS lowered the alert level status from Alert Level 3 to Level 2.

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 800 meters and 400 meters. 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.

In June, sulfur dioxide levels around the volcano recorded a massive increase, 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 also released the same vog as in June 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 3,402 tons per day.

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.