100 Mayon volcanic earthquakes recorded in just 10 hours

MAYON VOLCANO. Lava flows from Mayon Volcano in Albay on June 11, 2023, in this picture obtained by Reuters from social media.

Nehemiah Manzanilla Sitiar

Alert Level 3 remains in effect, but Phivolcs is closely monitoring the ‘sudden change’ in volcanic earthquakes and ground deformation

MANILA, Philippines – There has been a spike in volcanic earthquakes and ground deformation at Mayon Volcano in Albay, state volcanologists warned on Monday, June 26.

The Philippine Institute of Volcanology and Seismology (Phivolcs) first recorded “an increasing number of weak and shallow volcanic earthquakes” on Saturday, June 24.

These were followed by 102 volcanic earthquakes during a 24-hour period between Sunday, June 25, and early Monday.

Phivolcs then recorded 100 more volcanic earthquakes between 5 am and 3 pm on Monday, or in just a 10-hour period.

“Some of the analyzed earthquakes that could be located emanated from the summit lava dome, indicating origins from lava extrusion processes at the crater,” the agency said in an advisory.

A lava dome is an accumulation of “highly viscous lava above or near the vent/s where they were erupted,” while extrusion means molten rock is being pushed out onto the surface.

In the week preceding Saturday, Phivolcs only recorded at most 3 volcanic earthquakes in a 24-hour period. There were days when there were none.

Aside from the increasing number of volcanic earthquakes, there is also “a noticeable sharp jump in ground tilt on the southwest sector of the edifice” that began on Sunday.

Phivolcs noted that the Mayon unrest has so far been “dominated” by weak lava flows from the summit crater since the volcano’s status was raised to Alert Level 3 on June 8. There are still “sporadic” rockfall events and pyroclastic density currents, too.

Phivolcs stressed that while Alert Level 3 remains in effect, it is closely monitoring the “sudden change” in volcanic earthquakes and ground deformation.

The agency also reiterated that there should be no entry into the 6-kilometer-radius permanent danger zone, and communities within a 7- and 8-kilometer-radius from Mayon “must always be prepared.”

Phivolcs previously said the volcano’s condition “may change anytime”, with two out of three scenarios showing a potential declaration of Alert Level 4 and the third scenario possibly leading to Alert Level 5, the highest. – Rappler.com