Alert Level 4 remains as sulfur dioxide emission spikes in Taal Volcano

The amount of sulfur dioxide that has been emitted by Taal Volcano — indicating the upward movement of magma to the surface — has increased again, according to latest PHIVOLCS bulletin on Thursday morning.

As of the latest measurement on January 15, the sulfur dioxide emission was at an average of 4,186 tonnes per day — higher than the average of 1,686 tonnes per day that was recorded on January 14.

According to PHIVOLCS Volcano Monitoring and Eruption Prediction Division chief Mariton Bornas, the presence of this chemical compound in the atmosphere is an indicator of the magma's movement.

"Humihiwalay kasi 'yung sulfur dioxide kapag nasa malapit na sa bunganga ng bulkan 'yung umaakyat na magma. Kapag nasa malalim, naka-dissolve pa 'yan sa magma, hindi pa 'yan makahiwalay," she had said previously.

Short-lived dark gray ash plumes, 500 meters and 800 meters high, were generated by Taal Volcano at 6:17 a.m. and 6:21 a.m. on Thursday, respectively.

Ashes were dispersed in areas southwest to west of the main crater.

The PHIVOLCS, nevertheless, said the volcano's activity in the past 24 hours has "generally waned" to weak emission of steam-laden plumes 700 meters high which dispersed ash to the southwest.

"Mayroon din po tayong konsiderasyon na baka nga po kailangan nating tingnan kung ang activity ay medyo bumaba na, na puwede nating tingnan kung maibababa 'yung alert level," Bornas said at a press conference on Thursday morning.

"Sa stage na pong ito ngayon, hindi pa po natin tinatanggal ang panganib na maaaring pumutok nang malakas pero tintingnan na rin po natin ngayon 'yung possibility na mag-lull nang may considerable na tagal," she added.

Bornas said that if the lull period would be long, the alert level might also be downgraded, considering the situation of the evacuees in temporary shelters.

"Ito po 'yung isang medyong masalimuot na bahagi ng evacuation kapag medyo prolonged ang activity ng bulkan at may mga periods o panahon ng lull," she added.

From 5 a.m. on Wednesday to 5 a.m. on Thursday, 103 volcanic earthquakes were recorded —14 of which registered magnitudes one to four and were felt at Intensities I to III, according to PHIVOLCS.

This brings to 566 the total number of plotted volcanic earthquakes since Taal's initial activity on Sunday afternoon.

"Such intense seismic activity likely signifies continuous magmatic intrusion beneath the Taal edifice, which may lead to further eruptive activity," PHIVOLCS said.

Alert Level 4 remains in place as hazardous explosive eruption is possible within hours to days.

The Taal Volcano Island, the areas within the 14-kilometer radius from the main crater, and areas along the Pansipit River Valley must be evacuated due to hazards such as base surge and volcanic tsunami.

Other communities around the volcano must also prepare against the effects of heavy and prolonged ashfall.

The airspace around Taal Volcano remains unsafe to aircraft due to risks that may be posed by airborne ash and ballistic fragments from the eruption column. —KBK/RSJ, GMA News