Increased sulfur dioxide emissions, volcanic quakes observed in Taal Volcano

Taal Volcano has not slumbered yet despite being apparently calm as of Tuesday, based on parameters being used to assess its activity while Alert Level 3 remains.

According to the Philippine Institute of Volcanology and Seismology (PHIVOLCS), the volcano's sulfur dioxide emission increased again at an average of 231 tonnes per day on February 3.

It was more than double the previous measurement of 97 tonnes per day, which was recorded on February 1.

The presence of the said compound in the atmosphere indicates the upward movement of magma to the surface, according to PHIVOLCS.

#TaalVolcano https://t.co/4wMIC7XjTb pic.twitter.com/aZqms501fa

— PHIVOLCS-DOST (@phivolcs_dost) February 4, 2020

During the height of Taal Volcano's unrest three weeks ago, the sulfur dioxide emissions reached up to over 5,000 tonnes per day.

Meanwhile, the Taal Volcano Network detected 233 volcanic earthquakes, including eight low-frequency events, in the past 24 hours.

According to the United States Geological Survey, low-frequency earthquakes are "caused by cracks resonating as magma and gases move toward the surface."

"They are often seen prior to volcanic eruptions, but their occurrence is also part of the normal background seismicity at some volcanoes and their occurrence does not necessarily indicate that an eruption is imminent," the USGS said.

The PHIVOLCS maintained that the recorded seismic activities "signify magmatic activity beneath the Taal edifice that could lead to eruptive activity at the Main Crater."

In the past 24 hours, weak emission of steam-laden plumes, 50 to 500 meters tall, was observed at the volcano's main crater. The plumes drifted southwest.

PHIVOLCS warned the public that "sudden steam-driven and even weak phreatomagmatic explosions (involving both magma and water), volcanic earthquakes, ashfall, and lethal volcanic gas expulsions can still occur and threaten areas within Taal Volcano Island and nearby lakeshores."

It advised that Taal Volcano Island and communities west of the island within a seven-kilometer radius from the main crater should remain off-limits.

Areas outside the seven-kilometer radius have to be assessed by authorities for damages and road accessibilities. Returning residents must also be prepared to evacuate in case of the volcano's renewed unrest, it added.

Further, those living beside active river channels with thick deposits of volcanic ash from Taal's previous eruption must be vigilant for possible lahars when there is heavy and prolonged rainfall.

Aircraft must also avoid flying close to the volcano due to hazards that may be posed by airborne ash and ballistic fragments from sudden explosions and wind-remobilized ash, PHIVOLCS said. —Dona Magsino/KG, GMA News