MANILA – Seven volcanic earthquakes were observed around Taal Volcano over the weekend, the Philippine Institute of Volcanology and Seismology (Phivolcs) said.
In a bulletin issued on Sunday morning, Phivolcs said Alert Level 1 remains in effect over Taal Volcano.
Under Alert Level 1, hazardous eruption from Taal Volcano is not imminent, but the public is reminded that ''the Main Crater should be strictly off-limits because sudden steam explosions may occur and high concentrations of toxic gases may accumulate."
''The northern portion of the Main Crater rim, in the vicinity of Daang Kastila Trail, may also become hazardous when steam emission along existing fissures suddenly increases,'' Phivolcs added.
Phivolcs noted that the entire Taal Volcano island is considered a permanent danger zone.
Phivolsa said field measurements done last August 21 showed that the eastern sector of the main crater lake recorded an increase in water temperature from 32.3°C to 32.9°C; an increase in water level from 0.71 meter to 0.77 meter; and slight decrease in acidity from pH 3.05 to 3.08.
Carbon dioxide (CO2) emission at the main crater lake increased from 698 tons/day in June 2014 to 1,800 tonnes/day in the July 23-25, 2014 survey.