THE Bulusan Volcano had another phreatic eruption on Sunday dawn, June 12, 2022, the Philippine Institute of Volcanology and Seismology (Phivolcs) said.
Phivolcs said the event that occurred around 3:37 a.m. lasted for 18 minutes, although the eruption plume that rose to one kilometer high was not visible on camera monitors.
Phreatic eruption happens when magma heats groundwater or surface water. The steam that causes boiling water produces explosions.
Phivolcs reminded the public that Bulusan Volcano is still at Alert Level 1, which means that it is currently in an abnormal condition.
Due to the increased possibilities of sudden and hazardous phreatic eruptions, Phivolcs reminded local government units and the public that entry into the four-kilometer radius Permanent Danger Zone (PDZ) must be strictly prohibited and that vigilance in the two-kilometer Extended Danger Zone (EDZ) on the southeast sector must be exercised.
In a television interview, Phivolcs Director Renato Solidum said the eruption caused another ashfall, particularly in the town of Juban which was also affected by a similar event last week, June 5.
Sorsogon Governor Francis Escudero said there were also reported ashfall in some barangays in Casiguran and Magallanes.
The agency also reminded civil aviation authorities to advise pilots to avoid flying close to the volcano's summit as ash from any sudden phreatic eruption can be hazardous to aircraft.
“Furthermore, people living within valleys and along river/stream channels especially on the southeast, southwest and northwest sector of the edifice should be vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall should phreatic eruption occur,” Phivolcs said.
However, Solidum said the Bulusan Volcano has not yet met the parameters needed to escalate the Alert Level 2, but when the eruption became more intense, pyroclastic flow which involves ashes and stones is possible.
"Wala tayong nakikitang parametro na may magma na umaakyat ng bulkan... Ang magmatic eruption ay mas delikado,” he said.
(We don't see any parameters with magma rising from the volcano... magmatic eruption is more dangerous.)
“Base sa mga deposito, may mga mas delikadong eruption ang Bulusan... Sa ngayon, mga phreatic eruption ang ating nakikita... Dahil maliliit pa ang lindol, 'yung pressure kung mayroon man ay sa ibabaw lang," he added.
(Based on the deposits, Bulusan has more dangerous eruptions... Right now, we are seeing phreatic eruptions... Because the earthquakes are still small, the pressure if there is any is just above.)
(SunStar Philippines)