Taal Volcano Records 20 Earthquakes in 24 Hours, PHIVOLCS Maintains Alert Level 1

Key facts

• Taal Volcano experienced 20 volcanic earthquakes on Sunday, May 3.
• PHIVOLCS recorded weak steam plumes drifting southwest from the volcano.
• On May 1, Taal emitted 590 tonnes of sulfur dioxide.
• Alert Level 1 (Low-level unrest) remains in effect for Taal Volcano.
• Entry into Taal Volcano Island, especially Main Crater and Daang Kastila fissures, is prohibited.
• Boating on Taal Lake and aircraft flights near the volcano are not allowed.
• Resident Volcanologist Paolo Revina described majority of observations as 'weak only'.

Unrest Beneath the Surface: 20 Earthquakes Rock Taal

Taal Volcano in Batangas province recorded 20 volcanic earthquakes on Sunday, signaling renewed unrest beneath its crater, according to the Philippine Institute of Volcanology and Seismology (PHIVOLCS). The seismic swarm, detailed in the agency's Monday bulletin, marks a significant uptick from the single earthquake logged during the previous 24-hour monitoring period from May 2 to May 3. PHIVOLCS also observed weak steam plumes rising from the volcano and drifting southwest, a pattern consistent with low-level hydrothermal activity. The agency noted that on May 1, Taal released 590 tonnes of sulfur dioxide, a key indicator of magmatic degassing.

Alert Level 1 Maintained Despite Increased Activity

Despite the surge in earthquakes, PHIVOLCS has kept Taal Volcano under Alert Level 1, which denotes low-level unrest. Resident Volcanologist Paolo Revina told DAILY TRIBUNE that the majority of observations remain weak, suggesting no immediate escalation. 'Majority of the observations are weak only,' Revina said, tempering concerns of a major eruption. The agency's latest 24-hour monitoring from midnight May 2 to midnight May 3 also tracked activity at three other active volcanoes: Bulusan in Sorsogon, Kanlaon in Negros Island, and Mayon in Albay. For Taal, the monitoring recorded only one volcanic earthquake during that period, underscoring the sudden increase on Sunday.

Strict Prohibitions Enforced in Permanent Danger Zone

PHIVOLCS reiterated that entry into Taal Volcano Island, designated as the Permanent Danger Zone (PDZ), remains strictly prohibited. The ban specifically covers the Main Crater and Daang Kastila fissures, areas prone to sudden steam-driven explosions. Additionally, the agency warned against occupancy and boating on Taal Lake, as well as flying aircraft close to the volcano. The restrictions aim to mitigate risks from potential hazards, including phreatic or gas-driven explosions and lethal accumulations or expulsions of volcanic gas. The agency also noted temporary inflation of Taal Volcano Island, a sign of ground deformation that could precede further activity.

Hazards on the Horizon: What Taal Could Unleash

PHIVOLCS has identified several possible hazards from Taal Volcano under its current state of unrest. These include steam-driven or phreatic explosions, which occur when water interacts with hot volcanic material, and gas-driven explosions from accumulated volcanic gases. Lethal accumulations of gas, such as sulfur dioxide, pose a particular threat to life in enclosed or low-lying areas. The agency's monitoring network continues to track seismic, ground deformation, and gas emission data to detect any changes in activity. The 590 tonnes of sulfur dioxide emitted on May 1, while elevated, remains within levels seen during previous periods of low unrest.

Wider Context: Four Active Volcanoes Under Watch

Taal is one of four active volcanoes in the Philippines currently under PHIVOLCS observation, alongside Bulusan, Kanlaon, and Mayon. The agency's 24-hour monitoring from May 2 to May 3 recorded low to high levels of volcanic activity across these sites, reflecting the archipelago's position along the Pacific Ring of Fire. Mayon Volcano, in particular, has drawn attention due to ashfall that prompted the Department of Social Welfare and Development to pre-position over 300,000 food and non-food items. However, no flight cancellations have been directly linked to Taal's current unrest, unlike those reported amid Mayon's activity.

Outlook: Vigilance Without Panic

PHIVOLCS continues to advise the public to remain vigilant but not alarmed, as Alert Level 1 indicates no imminent eruption. The agency's resident volcanologist emphasized that the weak nature of current observations suggests a low probability of escalation in the near term. Nonetheless, the sudden increase in earthquakes serves as a reminder of Taal's volatile nature. Authorities have urged residents and tourists to strictly adhere to the prohibited zones and to stay informed through official PHIVOLCS bulletins. The agency's monitoring network remains on high alert, ready to adjust the alert level if seismic or gas emission data indicate a shift toward more dangerous activity.

The bottom line

• Taal Volcano recorded 20 volcanic earthquakes on May 3, a sharp increase from one quake the previous day.
• PHIVOLCS maintains Alert Level 1, indicating low-level unrest, with weak steam plumes and 590 tonnes of sulfur dioxide emitted.
• Entry into Taal Volcano Island, Main Crater, and Daang Kastila fissures is strictly prohibited due to explosion and gas hazards.
• Resident Volcanologist Paolo Revina described observations as 'weak only,' suggesting no immediate eruption threat.
• Temporary inflation of Taal Volcano Island has been detected, a sign of ground deformation that requires continued monitoring.
• The Philippines has four active volcanoes under observation, with Taal's activity part of a broader pattern of unrest across the archipelago.