The Philippine Institute of Volcanology and Seismology (Phivolcs) said Tuesday that the cracks that emerge on the roads in Batangas are signs that magma or molten rock are moving towards the Taal volcano.
“Ito nao-observe natin na tuloy tuloy na paglindol na malalaki kasama na ‘yung cracking ay naghuhudyat na meron talagang magma na umaakyat pa sa Taal,” said Mariton Bornas, head of the volcano monitoring and eruption prediction division at Phivolcs.
(What we are observing now, earthquakes and fissures, are signs that magma is still rising in Taal.)
At least 335 volcanic earthquakes were monitored between Sunday and Tuesday at 10 a.m. In the area. The strongest was a magnitude 4.1.
“For volcanic earthquakes, this is strong,” Bornas said.
The Taal volcano was first placed at Alert Level 1 in March 2019 after the Phivolcs monitored a substantial number of weak earthquakes in the area. Swarms of earthquakes are usually controlled before a volcanic eruption.
Meanwhile, floor fractures were observed in various parts of Batangas, including the cities of Agoncillo, Lemery, San Nicolás and Talisay, destroying some houses.
Bornas, who has been studying Taal closely, said that during the past eruptions fissures appeared before a major or explosive eruption.
“Fissures appear and then the ground sinks after a major eruption,” Bornas said, adding that the fall is caused by the vacuum created underground when the volcano discharges magma to the surface.
However, Bornas clarified that magma cannot flow from fissures. “These are characteristics of soil deformation,” he said.
It is not clear if the fissures will cause an explosive eruption in a few days, but Bornas said it is similar to what happened in 1911.
Bornas, who recently published a magazine article with other experts about Taal’s history, recalled how historical accounts recorded the 1911 explosion as a low-level activity in the main crater on January 27, followed by the appearance of fissures. January 28. It was on January 30 that the great eruption occurred.
It is also notable that the cracks in 1911 occurred in the same areas in Batangas: Lemery, San Nicolás, Taal, Talisay and Tanauan.
When asked if this meant that residents should leave areas that showed signs of fissures, Bornas said: “I think they should have already evacuated. We would like to reiterate the application of the evacuation. ”
The communities around the 14-kilometer area of the Taal volcano should have been evacuated, according to the advice of the Phivolcs.
Bornas also clarified that the presence of fissures cannot predict an explosive eruption; only that it is an indication that there is a large volume of magma movement.
She said the danger now is that while there is little surface activity on the volcano, the passage to the surface has already cleared after hours of groundwater explosions during the first day.
“Taal has been opened. If magma comes from below, you can ascend quickly. There are no more blockages, ”he said.
During press conferences, journalists asked for other effects of the eruption, including reports that parts of the lake have turned green.
Bornas said that while it is difficult to evaluate such reports since experts have not seen it, during the eruption of 1911 there have been reports that one of the smaller lakes inside the Taal caldera is turning green.
“They called it green lagoon. The water turned green due to the high sulfur content, ”he said, adding that sulfur oxide only appears when magma almost reaches the surface.
He assured the public that the Phivolcs are continuously monitoring the volcano. At the same time, he reiterated that at alert level 4, people should understand that an explosive eruption can occur at any time.