MANILA, Philippines (UPDATED) – The threat of a hazardous Taal Volcano eruption remains on Thursday, January 16, as "intense seismic activity" persists despite "weak emission" of ash plumes.
In an update at 5 pm on Thursday, the Philippine Institute of Volcanology and Seismology (Phivolcs) said it observed "weak emission of steam-laden plumes 800 meters high" coming from the main crater in the last 8 hours.
"A total of 9 discrete weak explosions were recorded by the Taal Volcano Network," Phivolcs added.
The agency earlier said it spotted "short-lived dark gray ash plumes" at 6:17 am and 6:21 am on Thursday, 500 meters and 800 meters high, respectively. These plumes "dispersed ash southwest to west of the main crater." (READ: Taal Volcano's 2020 eruption: What we know so far)
Though there is weakening emission, residents near Taal Volcano must stay on guard "against the effects of heavy and prolonged ashfall," said Phivolcs. The airspace around Taal remains off-limits, too.
There have also been 595 volcanic earthquakes since 1 pm last Sunday, January 12, the day Taal started erupting. Of these, 176 were felt with intensities ranging from Intensity I to V.
Just from 5 am to 3 pm on Thursday, "there were 30 volcanic earthquakes plotted, including one earthquake which was felt at Intensity I."
"This signifies continuous magmatic intrusion beneath the Taal edifice, which may lead to further eruptive activity," Phivolcs said.
The agency added that no additional fissures or cracks have been mapped and reported.
"Existing ones are in the identified barangays of Lemery, Agoncillo, Talisay, and San Nicolas in Batangas province as indicated in the January 15, 2020 5 pm update," Phivolcs said.
Since volcanic unrest continues, Alert Level 4 remains in place. This means a hazardous eruption is "imminent" or may happen "within hours to days." But at the same time, Phivolcs said it is taking into account the easing of the emission.
"Sa stage na po ngayon, hindi pa po natin tinatanggal 'yung panganib na maaaring may malakas, pero tinitignan na rin po natin 'yung possibility ngayon na mag-lull ng considerable na tagal.... Medyo tricky 'yung kalagayan ngayon," said Maria Antonia Bornas, chief of the Phivolcs Volcano Monitoring and Eruption Prediction Division, in a press briefing on Thursday morning.
(At this stage, we're not ruling out the possibility of a hazardous eruption yet, but we're also now looking at the possibility that there may be a lull for a considerable period of time.... The situation is a bit tricky right now.)
Bornas later said in another press briefing on Thursday afternoon: "We have to step back and look at other scenarios.... Nagkaroon ng lull, so we need to evaluate kung ito ay magiging long-term trend or magkakaroon tayo ng explosive buildup soon (There's been a lull, so we need to evaluate if this would become a long-term trend or whether we would have an explosive buildup soon)."
The highest possible alert level is 5, which means a hazardous eruption is already in progress. (READ: TIMELINE: Taal Volcano eruptions since 1572)
Phivolcs reiterated that there must be "total evacuation" of Taal Volcano Island as well as high-risk areas within a 14-kilometer radius from the main crater and "along the Pansipit River Valley where fissuring has been observed." (WATCH: Fishermen risk lives for catch around restive Taal Volcano)
Thousands of people are staying in evacuation centers. At least 3 evacuees have died, but it is unclear if their deaths were related to the ashfall or were solely because of preexisting medical conditions. (READ: Officials face challenges with relief, sick evacuees due to lockdown in Batangas)