Intensity 3 and Intensity 1 volcanic earthquakes were felt in two villages near Taal Volcano yesterday, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported.

Phivolcs said in its April 20 bulletin that a total of 13 volcanic earthquakes were detected in Taal Volcano during the past 24 hours.

One of the quakes, which occured at 3:15 p.m. Tuesday, was felt at Intensity 3 in Barnagay Calauit and Intensity 1 in Barangay Pira-Piraso.

Phivolcs said that the tremor was accompanied by rumbling sounds.

In the Phivolcs Earthquake Intensity Scale, Intensity 3 is classified as "weak", but it is felt by many people indoors specially in upper floors of buildings.

In events of an Intensity 3 tremor, Phivolcs said, "Vibration is felt like the passing of a light truck. Dizziness and nausea are experienced by some people."

Meanwhile, Phivolcs said that field observation and measurements conducted at the eastern sector inside the main crater lake yestery showed that the temperature increased from 30.5°C to 31.5°C.

Alert Level 2 remains hoisted over the volcano, meaning "magma has been intruding towards the surface."

Phivolcs said the main crater, the Daang Kastila trail and Mt. Tabaro are strictly off-limits, because sudden steam-driven explosion may take place in these areas, adding that "high concentration of toxic gases may accumulate."

"Breathing air with high concentration of gases can be lethal to human, animals and even cause damage to vegetation," Phivolcs warned.