The Philippine Institute of Volcanology and Seismology has recorded four volcanic earthquakes in Taal Volcano in Batangas as it continued to show signs of unrest.

In a Saturday advisory, Phivolcs said the volcanic tremors lasted from one to two minutes with low-level background tremors in the past 24 hours.

However, Taal's volcanic sulfur dioxide (SO2) gas emission declined to  7015 tonnes Wednesday compared to 10,718 tonnes recorded on Saturday — pronounced upwelling of hot volcanic fluids in the main crater lake.

While its voluminous emission decreased to 1,200 meters tall on Saturday from 2,500 meters tall on Friday, drifting northwest.

Phivolcs reiterated that entering into the permanent danger zone, especially in the main crater and Daang Kastila fissures remain prohibited.

Occupancy and boating on Taal Lake are likewise not allowed and warnings to flying aircraft close to the volcano were raised.

The temperature in the main crater lake is 66.5.

Taal's unrest may induce steam-driven or phreatic or gas-driven explosions, volcanic earthquakes, minor ashfalls and lethal accumulations, or expulsions of volcanic gas.