Volcano landscape altered
MANILA, Philippines — Taal Volcano is swelling, a portion has sunk and the entire volcano island has tilted slightly, indicating a “resupply” of magma or molten rock rising to the surface that presages a powerful eruption amid the ongoing lull.
This was according to the Philippine Institute of Volcanology and Seismology, whose official said Taal appeared to be “recharging.” Phivolcs has maintained Alert Level 4 meaning a destructive eruption is imminent within days or even hours.
“There is resupply of magma from below based on earthquakes and ground deformation,” Science Undersecretary and Phivolcs officer-in-charge Renato Solidum Jr. said.
Solidum also said the silent activity beneath Taal has significantly altered the landscape of the volcano island.
He said some parts of the northeastern portion of the volcano have sunk while the entire volcano has swelled.
“The island has slightly tilted while being pushed. Some portions in the northeastern side are sinking. Maybe the houses there are already under water,” Solidum said.
Phivolcs volcano monitoring and eruption prediction division chief Mariton Bornas said the ground around the volcano has swollen except in the northeastern part. Swelling of a volcano signals an accumulation of magma near the surface.
Even before its eruption on Jan. 12, Solidum said they had warned the public regarding the volcano island’s being a permanent danger zone.
“We have been warning for years that permanent settlement is prohibited on the island,” he said.
He again appealed to the public to stay away from the volcano’s 14-kilometer radius danger zone.
“If it reaches the crater, it could cause a strong explosion,” Solidum said, referring to the magma buildup. Alert Level 4 is the second highest of the five-step alert on Taal.
He said more than 600 volcanic tremors have been recorded since Sunday, signifying a continued rise of magma.
The Phivolcs chief also noted the high concentration of sulfur dioxide (SO2), which means that magma is actively degassing beneath Taal.
The SO2 was measured at 4,353 tons yesterday. SO2 is a major gas component of magma.
More earthquakes
On Sunday, some Taal evacuees spent the night outside an evacuation center in Batangas after a magnitude 4.6 earthquake shook the province.
The quake occurred at 8:59 p.m., with its epicenter traced some four kilometers southwest of Mabini, Batangas, Phivolcs said.
In Batangas, it was felt at Intensity 5 – classified as strong – in Mabini and Bauan; Intensity 4 in Batangas City and Santo Tomas; Intensity 3 in Malvar, Cuenca, Tanauan, San Pascual and Calatagan.
It was also felt at Intensity 3 in Puerto Galera, Oriental Mindoro; and in San Pablo, Laguna. In Alfonso, Cavite and San Teodoro in Oriental, Mindoro, the tremor was felt at Intensity 2.
Later on the same day at 10:02 p.m., another tremor, with a magnitude of 4, struck three kilometers southwest of Mabini.
According to reports, Taal evacuees who sought shelter at the Bauan Technical High School spent the night outdoors for fear the structure might collapse.
No damage or aftershocks, however, were reported, Phivolcs said.
Solidum said a local fault caused the temblor. He said the magnitude 4.6 quake was tectonic in origin.
“In April 2017, there was a series of quakes in that place (Batangas), and a movement along that fault triggered the quake last (Sunday) night,” Solidum said.
However, he said Phivolcs is studying whether the tectonic quake could be linked to Taal Volcano’s unrest, which already generated over 700 volcanic quakes since its initial eruption on Jan. 12.
As threats of a destructive eruption persist, even the Philippine Coast Guard (PCG) in Batangas has been ordered to take precaution – specifically by moving its forces back by one kilometer from the 14-kilometer danger zone.
The National Disaster Risk Reduction and Management Council (NDRRMC) issued the order.
PCG Task Force Taal commander Commodore Artemio Abu yesterday said he was informed of the order last Sunday.
“I told my men that we would observe that order but if there are still people or local government personnel within the 14-kilometer area, I told the Coast Guardsmen to calibrate their actions. We have to sacrifice and be with them,” Abu said.
“The Philippine Coast Guard would not be the first to jump ship. This was the example I gave my men and they were inspired, they were motivated.”
The Coast Guard official said it was possible that they were being told to move backward for their own safety.
“Everything that happens here is preemptive. Sometimes there would be succeeding earthquakes at night,” he said.
Despite the order and the likelihood of a deadly eruption, Abu said some members of the uniformed service, including PCG personnel, would continue to patrol in and around Taal “because we saw that the reason why we were there was to serve the Filipino people.”
Told of possible reprimand from the NDRRMC, Abu said PCG chief Adm. Joel Garcia has expressed his trust in the Batangas coast guard officer.
“Since I am on the ground, Admiral Garcia has given me liberty to decide. Of course, his instruction was to decide based on the maximum care for our people,” Abu pointed out. – Evelyn Macairan
Source: https://www.philstar.com/headlines/2020/01/21/1986499/phivolcs-taal-recharging-powerful-eruption