By Alexandria San Juan
State volcanologists said new fissures or cracks on the ground were observed in several towns in Batangas as a series of tremors rumbled the province amid threats of Taal Volcano’s hazardous explosive eruption.
These fissures, according to the Philippine Institute of Volcanology and Seismology (Phivolcs), were found in the barangays of Sinisian, Mahabang Dahilig, Dayapan, Palanas, Sangalang, and Poblacion in the town of Lemery; Pansipit in the municipality of Agoncillo; Poblacion 1, Poblacion 2, Poblacion 3, and Poblacion 5, in the town of Talisay; and Poblacion in San Nicolas.
Phivolcs said a fissure was also documented across the road connecting the municipalities of Agoncillo and Laurel.
According to Phivolcs’ Volcano Monitoring and Eruption Prediction Division chief Mariton Bornas, the new fissures were produced by the intrusion of magma into the Taal edifice.
“Kapag may magma na tumutulak paakyat ng bulkan, kapag medyo malaki ang volume na sumisirit paakyat, talagang nade-deform nito ang mas malaking area, hindi lang ‘yung volcano island,” Bornas said in a press briefing on Tuesday.
(When there is magma rising in the volcano, when there is a large volume of magma rising upwards, it deforms a much larger area, not only the volcano island.)
Bornas added that fissuring, as well as the strong and more frequent quakes near Taal, also indicates the movement of magma beneath the volcano which may lead to an explosive eruption.
“Ang hinuhudyat ng malalakas na lindol at nung fissuring na nararanasan ngayon sa Batangas ay mayroon po tayong malaking volume ng magma na ini-intrude sa edifice at maaari po itong i-putok bilang isang malakas na eruption,” she explained.
(The strong quakes and fissuring now being experienced in Batangas are signs pointing to a large volume of magma intruding into the edifice and this could be released in a huge eruption.)
Bornas cited historical records that fissures were also spotted in the same areas where the new cracks were found a day before Taal’s eruption in 1911.
“Kung susunod ito sa 1911, pwedeng ganito ang maaari nating i-expect, although hindi natin sinasasabi na ganitong-ganito ang mangyayari, pero pwede,” she said.
(If this will be like the 1911 eruption, we might expect the same thing, thought we can’t say it will be exactly the same, but maybe.)
The Phivolcs official warned that there is a possibility that the ground where the cracks were found might sink.
“Ang pwedeng mangyari d’yan, ngayon hindi pa masyadong humihiwalay yung lupa, pero nung 1911 pagkatapos ng malakas na pagputok, lumubog yung lupa d’yan,” Bornas said. “Fissuring muna and then eruption and then lumubog.”
(What could happen, now that the land is not separating yet, but in 1911, after a huge eruption, the ground sank. Fissuring first, then eruption, then ground subsidence.)
Bornas said residents of areas where the cracks were spotted should leave their homes and evacuate to safer areas.”Dapat naka-evacuate na ang mga areas na ‘yun (They should have evacuated from those areas). We would like to reiterate, yung enforcement ng evacuation (the enforcement of evacuation) is very important para sa (for the) safety ng ating mga kababayan (of our countrymen).”
Alert Level 4, a notch below the highest alert level, still remains in effect over Taal Volcano. This means a hazardous explosive eruption of Taal is still possible within hours to days. Level 5, the highest, indicates an ongoing eruption, Phivolcs said.
In the latest bulletin issued by the agency, Taal Volcano’s ongoing eruption has been characterized by “continuous magmatic and hydrovolcanic activity.” It continued to spew lava fountains which generated 800-meter tall dark gray steam-laden plumes that drifted to the southwest of Taal.
The Philippine Seismic Network also recorded another 49 volcanic quakes in the Taal region from 2 a.m. to 10 a.m. on Tuesday, seven of which were felt with intensities ranging from Intensity II to IV in Tagaytay City.
Tuesday’s recorded volcanic tremors show 335 quakes in Taal Volcano since Sunday afternoon.
Phivolcs also emphasized the total evacuation of Taal Volcano Island and areas at high risk to pyroclastic density currents and volcanic tsunami within a 14-kilometer radius from the volcano’s main crater.
Areas around Taal Volcano are also advised to guard against the effects of heavy and prolonged ash fall, while civil aviation authorities were advised to warn the aviation industry to avoid the airspace around the volcano as airborne ash and ballistic fragments from the eruption column pose hazards to aircraft.
Taal Volcano’s sudden eruption on Sunday, amid signs of its restiveness in recent months, caught thousands of unaware residents and tourists visiting the picturesque lake by surprise.
Prior to its recent eruption, Phivolcs said that Taal has not erupted since 1977, but there was volcanic unrest recorded in 2011, 2012, and 2014.
Phivolcs said Taal is second most active volcano in the country, with at least 34 eruptions recorded since 1572.
Though tagged as the world’s smallest volcano, Taal is also one of the deadliest, following its violent eruptions in 1754, 1911, and 1965 that left thousands of casualties in the wake of its various volcanic hazards.