(Eagle News) — The Philippine Institute of Volcanology and Seismology (PHIVOLCS) has raised the alert level over Taal.
In an advisory on Tuesday, March 9, PHIVOLCS said the raising of the alert level from alert level 1 to 2 was because the volcano has been exhibiting increased unrest since Feb. 13.
For instance, PHIVOLCS said the Taal Volcano Network (TVN) recorded a total of twenty-eight volcanic tremor episodes, four low-frequency volcanic earthquakes, and one hybrid earthquake at shallow depths of less than 1.5 kilometers beneath Taal Volcano Island or TVI in the past 24 hours.
Volcanic tremors have also “increased seismic energy compared to previously recorded episodes and ranged between three to 17 minutes in duration,” PHIVOLCS said.
-Increasing tremor events –
It said the total number of volcanic tremor events rose to 866 since the onset of increased activity on February 13.
“In addition to these, a total of 141 low-frequency volcanic earthquakes (LFVQs) have occurred within one (1) kilometer depths beneath TVI and immediate vicinities. Overall, seismic activity in the past month indicates increased magmatic and hydrothermal activity at shallow depths beneath TVI,” PHIVOLCS said.
According to PHIVOLCS, there were also changes in the main crater lake.
Survey observations in mid-February recorded a temperature high of 74.6ºC and continuing increase in acidity to pH 1.59 from a pH of 2.79 in January 2020, PHIVOLCS said.
“Increasing acidity is caused by sustained volcanic gas input into the shallow hydrothermal system that feeds into the lake, signifying degassing of magma intruded at depth during the January 2020 eruption,” PHIVOLCS added.
PHIVOLCS also noted ground deformation and microgravity changes.
According to PHIVOLCS, an alert level 2 means there is increased unrest at the volcano, which also means that there is “probable magmatic activity that may or may not lead to an eruption.”
PHIVOLCS reminded the public that Taal Volcano Island is a Permanent Danger Zone (PDZ) and that entry into TVI, especially the vicinities of the Main Crater and the Daang Kastila fissure, “must remain strictly prohibited.”
“(Department of Science and Technology)-PHIVOLCS is closely monitoring Taal Volcano’s activity and any new significant development will be immediately communicated to all stakeholders,” PHIVOLCS said.
(Eagle News Service)