Batangas, Philippines – The Philippine Institute of Volcanology and Seismology (Phivolcs) has raised the alert level at Taal volcano from 1 to 2 due to the increasing frequency of volcanic earthquakes in the area.
Taal, located 65 kilometers south of Manila, is one of the most unstable of the country’s 22 known active volcanoes with 33 recorded eruptions, the last one in 1977.
Experts raised the second of a five-level alert on Taal yesterday. The Phivolcs said volcanic quakes in the area have been occurring since April and the crater lake was heating up.
Allan Loza, officer-in-charge of Phivolcs Talisay said based on their monitoring, the volcanic earthquakes detected per day since April 26 have raised to 32 high frequency volcanic earthquakes and continuously increasing as of presstime.
Subsequently, the Phivolcs immediately released an advisory preventing the public to visit the crater area of Taal, specifically the Daang Kastila trail.
In addition, a low frequency type volcanic earthquake was also detected since June 2.
Meanwhile, the Regional Disaster Coordinating Council (RDCC) in Calabarzon (Cavite, Laguna, Batangas, Rizal, Quezon) said it had alerted nine Batangas towns after the alert level status of Taal volcano was raised to level 2 on Tuesday.
“We have advised our Batangas Provincial Disaster Coordinating Council (PDCC) to issue a memorandum to all concerned municipalities regarding the alert level 2,” said RDCC director Vicente Tomazar.
The nine towns in Batangas province include Agoncillo, San Nicolas, Santa Teresita, Laurel, Lemery, Talisay, Tanauan City, Balete, and Mataas na Kahoy.
Officials of the tourist city of Tagaytay in Cavite, from which Taal volcano is also viewed, were also alerted to prohibit its tourists from trekking to the crater which is considered to be a danger zone.
Tomazar said if the alert level status hits level 3 under continuous monitoring, that is the time the authorities would activate its contingency plan and enforce evacuation of residents.
Phivolcs said the temperature measurement of the main crater of the lake had increased to 34°C as of May 24, higher by 2°C from the previous measurement on May 11.
“Steaming activities at the northern and northeast sides of the main crater occasionally intensified, sometimes accompanied by audible hissing sounds,” Loza said.
Phivolcs said the recorded high frequency volcanic earthquakes could be the result of active rock fracturing associated with magma intrusion beneath the volcano.
The fractures served as passageways through which hot gases from the intruding magma could escape into the main crater of the lake, the Phivolcs official said
Loza said the seismic activity of Taal volcano have manifested since year 1992, 1994, 2000, 2004 and now 2010. Its last eruption was on Oct. 3, 1977; but the most violent happened on Sept. 28-30, 1965.
Phivolcs reiterates that the whole Taal Volcano Island is a permanent danger zone and permanent settlement within this area is strictly prohibited.