By Ellalyn de Vera-Ruiz
The Philippine Institute of Volcanology and Seismology (Phivolcs) is closely monitoring Taal Volcano in Batangas after the active volcano recorded 87 quakes within the 24-hour observation period.
Taal Volcano (WIKIPEDIA/ MANILA BULLETIN)
From 8 a.m. Sunday to 8 a.m. Monday, Taal Volcano’s seismic monitoring network registered 87 volcanic earthquakes, higher than the previous 24-hour monitoring of 45 volcanic quakes.
One of the earthquakes, which occurred at 7:54 a.m. last Sunday, was felt at Intensity 1 at Tibag and Alas-as, situated in the northern and southwestern sector of the volcano island, respectively.
Science and Technology Undersecretary and Phivolcs Director Renato Solidum said Taal Volcano started to act up more in the last couple of weeks.
“We are closely monitoring Taal Volcano,” he said. “We have noticed an increase in earthquake activity in the past several weeks and we are monitoring other parameters if there will be significant changes.”
According to Phivolcs, the main indicators of imminent eruption in Taal Volcano are: increase in frequency of quakes with occasional felt events accompanied by rumbling sounds, increase in temperature and level of main crater lake, development of new thermal areas and/or reactivation of old ones, ground swells or inflation and ground fissuring, increase in temperature of ground probe holes at Mt. Tabaro, sulfuric odor and acrid fumes, and fish kills and drying up of vegetation.
Last October 3, Phivolcs’ field measurements at the western sector of the main crater lake yielded an increase in water temperature from 32.6 degrees Celsius (°C) to 33.0 °C, no change in water level of 0.49 meter, and a decrease in acidity from a pH of 2.82 to 2.83.
Meanwhile, ground deformation measurements through precise leveling surveys from September 19 to 26 indicated inflation of the edifice consistent with recent results from continuous GPS data.
While “hazardous eruption is not imminent” Phivolcs still reminded the public that the main crater should be strictly off-limits because sudden steam explosions can occur and high concentrations of toxic volcanic gases can be released.
The northern portion of the main crater rim, in the vicinity of Daang Kastila Trail, can also become hazardous when steam emission along existing fissures suddenly increases.
Furthermore, the public is reminded that the entire volcano island is a permanent danger zone and permanent settlement is strictly prohibited.
Taal Volcano had a total of 33 historical eruptions with the last major eruption happening on October 3, 1977.