Upwelling or rising of “hot volcanic fluids” in Main Crater Lake reported
(Eagle News) — Taal Volcano spewed its “highest level of volcanic sulfur dioxide” on Saturday, July 3, with emissions that averaged 14,699 tons, contributing to more extensive volcanic smog or vog that is hazardous to health.
“This is a notice of high volcanic SO2 gas emission from Taal Volcano,” said the Philippine Institute of Volcanology and Seismology (PHIVOLCS) on Saturday night, 8 p.m.
“The highest levels of volcanic sulfur dioxide or SO2 gas emission and tall, steam-rich plumes from the Taal Main Crater have been recorded today. SO2 emission averaged 14,699 tonnes/day, the highest ever recorded in Taal, while upwelling in the Main Crater Lake generated steam plumes that rose 2,500 meters above Volcano Island,” Phivolcs said in its bulletin.
PHIVOLCS warned that this level of sulfur dioxide emission was similar to what had preceded the July 1 phreatomagmatic eruption.
“Elevated SO2 emission may be succeeded by eruptive activity at the Main Crater similar to increases in SO2 flux of 14,326 tonnes/day and 13,287 tonnes/day on 28 June and the morning of 1 July 2021, respectively, that preceded the short-lived phreatomagmatic eruption at 3:16 PM of 1 July,” it said.
-Warning on vog over lakeshore communities of Batangas-
In addition, the increased SO2, coupled with high relative humidities of 79-91% and wind velocities of 0 meters/second over Taal Lake based on All-Weather Stations data from the Taal Volcano Observatory and Volcano Island, is also likely to promote the formation of volcanic smog or vog over the lakeshore communities of Batangas Province,” Phivolcs explained.
Increasing volcanic earthquakes were also recorded in Taal Volcano since its first phreatomagmatic eruption on Thursday afternoon as volcanologists noted the “active upwelling of hot volcanic fluids” in the main crater lake.
-PHIVOLCS: Ongoing magmatic extrusion at Main Crater may drive explosions-
PHIVOLCS warned that the current sulfur dioxide parameters exhibited by Taal Volcano indicated magma was already at the main crater, and that this could lead to “succeeding explosions.”
“Current SO2 parameters indicate ongoing magmatic extrusion at the Main Crater that may further drive succeeding explosions..”
-Evacuation-
The agency strongly recommended that “Taal Volcano Island and high-risk barangays of Bilibinwang and Banyaga, Agoncillo and Buso-buso, Gulod and eastern Bugaan, Laurel, Batangas Province remain evacuated due to the possible hazards of pyroclastic density currents and volcanic tsunami should stronger eruptions subsequently occur.”
“The public is reminded that the entire Taal Volcano Island is a Permanent Danger Zone (PDZ), and entry into the island as well as high-risk barangays of Agoncillo and Laurel must be prohibited. All activities on Taal Lake should not be allowed at this time,” it said.
It said “communities around the Taal Lake shores are advised to remain vigilant, take precautionary measures against possible airborne ash and vog and calmly prepare for possible evacuation should unrest intensify.”
-Health checks advised due to increasing vog-
PHIVOLCS also said that “because of unprecedented high SO2 degassing from Taal Main Crater, local government units are additionally advised to conducts health checks on communities affected by vog to assess the severity of SO2 impacts on their constituents and to consider temporary evacuation of severely exposed residents to safer areas.”
“Civil aviation authorities must advise pilots to avoid flying over Taal Volcano Island as airborne ash and ballistic fragments from sudden explosions and pyroclastic density currents such as base surges may pose hazards to aircraft,” it added.
-Increasing volcanic quakes recorded-
PHIVOLCS recorded 48 volcanic earthquakes on Friday, up from the previous day’s 29 volcanic quakes. There were also a series of three short phreatomagmatic bursts that occurred at 10:25 AM, 10:47 AM, 11:01 AM and produced short jetted plumes that rose 100 meters above the Main Crater Lake on Friday, a PHIVOLCS bulletin said.
This was followed by “active upwelling of hot volcanic fluids of the Taal Main Crater Lake” in the afternoon, Phivolcs said.
On Friday, it continued to note “high levels of volcanic sulfur dioxide or SO2 gas emissions and steam-rich plumes” in Taal which even rose as as 3,000 meters from the main crater. These drifted southwest and north-northwest.
On Friday, July 2, the 48 volcanic earthquakes included two (2) volcano-tectonic earthquakes, forty (40) low frequency volcanic earthquakes, and six (6) volcanic tremor events which lasted up to four minutes. There was also low-level background tremor that has persisted since April 8 this year, Phivolcs said.
On Thursday, July 1, on the day the volcano first had its phreatomagmatic eruption, the Taal Volcano Network recorded twenty-nine (29) volcanic earthquakes, including one (1) explosion-type earthquake, twenty-two (22) low frequency volcanic earthquakes and two (2) volcanic tremor events having durations of three (3) minutes, and the low-level background tremor that has persisted since April 8.
Taal Volcano remains at alert level 3. PHIVOLCS is closely monitoring developments in the volcano, and could raise the alert level further if increasing volcanic unrest is observed.
(Eagle News Service)