By Alexandria San Juan
Apart from the hazards expected after eruption of Taal Volcano, state volcanologists said prolonged eruption of up to seven months could be the worst case scenario for the volcano’s intense unrest activity.
Philippine Institute of Volcanology and Seismology’s (Phivolcs) Volcano Monitoring and Eruption Prediction Division chief Mariton Bornas said Monday that Taal Volcano remains at Alert Level 4 which means that a “hazardous explosive eruption is possible within hours to days.”
Citing historical records of the volcano’s past eruptions, Bornas noted that Taal’s ongoing eruption could last for at least three days similar to the 1911 eruption, or as long as seven months like what happened in 1754.
“It could be short, it could be long. Hopefully, short lang kasi malaking dagok po iyan sa mga kababayan natin sa Batangas,” Bornas said in a press conference in Quezon City.
Phivolcs chief Renato Solidum said the agency was still monitoring possible hazards and worst case scenarios that could came up once the danger level in Taal Volcano was raised to five.
Among these looming volcanic hazards would be the pyroclastic density currents particularly base surge, which was the major hazard in Taal in its 1965 eruption.
Base surge, according to Bornas, is a turbulent mass of volcanic ash, rocks, and hot gases that laterally flows away from the base of an eruption column at very high speeds.
This hazard could cause casualties mainly from gas suffocation and shock wave impact; or injuries such as burns due to hot sand and ash.
Aside from this, Taal Volcano’s hazards include ashfall and ballistic projectiles, lava flow, volcanic earthquakes, ground fissuring and subsidence, lahars, volcanic lightning, and volcanic tsunami, which is usually up to 3 meters high only.
In an earlier advisory of Phivolcs, it said that the ash brought about by the ongoing eruption of Taal has already reached areas in Calabarzon, Metro Manila, and as far as Central Luzon.
Solidum advised the public to protect their mouths and noses through using N95 grade face masks or wet cloth or towel to prevent inhalation of fine ashfall and its sulfurous smell as this can cause irritation and breathing problems, especially among the elderly and children.
Motorists were also urged to drive with extreme caution as wet ash could cause poor visibility and, when wet, could make roads slippery.
Meanwhile, larger tephra, or fragmented volcanic particles such as ashes and rocks, called “volcanic bombs” are usually too heavy to transport in eruption columns and are ejected straight out of the volcanic vent as ballistic projectiles.
These ballistic projectiles, Solidum pointed out, may cause harm to people near the volcano or at least five kilometers from where the eruption would happen.
“Dapat wala nang tao sa island at malapit sa island na baka tamaan ng malalaking bato,” he said.
Phivolcs reiterated the need for a total evacuation of Taal Volcano Island and areas at high risk.
While still in Alert Level 4, Taal remains in its “intense unrest” activity with continuing seismic swarms, including harmonic tremor and “low frequency earthquakes” which are usually felt.
According to Bornas, they recorded a total of 269 volcanic earthquakes within the vicinity of Taas following its “phreatic” or steam-blast eruption on Sunday, with intensities ranging from Intensity II to V, and with magnitude reaching up to 4.1.
Solidum emphasized that frequent earthquakes in Taal implied that there’s a rising lava or magma beneath the volcano.
“Yun nga ang implication, na kapag maraming earthquake, may magma na umaakyat. Kapag dumami pa yung umakayat na magma, mabilis ang eruption. Kung mas mabilis, mas delikado din kasi mas malakas yung mangyayari,” he added.
Though tagged as the world’s smallest volcano, Taal is also classified as one of the deadliest following its violent eruptions in 1754, 1911, and 1965, leaving thousands of casualties due to various volcanic hazards it brought.
Taal spewed steam, ash, and small rocks Sunday morning which surprised unaware residents and tourists in the area.
Lava fountain of up to 750 meters high was also observed in the main crater of Taal from 2:49 a.m. to 4:28 a.m., Monday, classified by Phivolcs as magmatic eruption.
Prior to its recent eruption, Phivolcs said that Taal has not erupted since 1977, but there were volcanic unrest recorded in 2011, 2012, and 2014.
Based on the data from Phivolcs, Taal is among the 24 active volcanoes in the country with at least 34 eruptions recorded since 1572