Phivolcs: Mayon’s quakes surge as rockfall events, sulfur dioxide emissions drop
MANILA, Philippines — The Philippine Institute of Volcanology and Seismology (Phivolcs) on Sunday said it monitored a big increase in Mayon Volcano’s earthquakes during the past day.
In a bulletin, Phivolcs said it recorded 221 volcanic earthquakes from 5 a.m., August 12, to 5 a.m., August 13. The agency’s monitoring a day before only logged 42 volcanic earthquakes.
The 221 volcanic earthquakes included 111 tremors, which altogether lasted for 28 minutes, Phivolcs also said, describing that volcanic earthquakes are isolated events that occur separately from each other while volcanic tremors are continuous vibrations.
The agency recorded 58 tremors from 5 a.m., August 11, to 5 a.m., August 12.
Phivolcs likewise observed a decrease in Mayon’s rockfall events and pyroclastic density currents (PDC) from 201 and seven on August 11 to 152 and three on August 12, respectively.
The volcano’s sulfur dioxide emissions also dropped from 1712.765 metric tons on August 11 to 724.84 metric tons on August 12, it added.
State volcanologists further noted that Mayon’s slow effusion of lava flow has reached 2.8 kilometers (km) along Mi-isi Gully and 3.4 km along Bonga Gully, and 1.1 km along Basud Gully, while lava dome collapse on these gullies extended to 4 km from the crater.
Phivolcs warned residents that rockfalls, landslides, avalanches, ballistic fragments, lava flows, and moderate-sized explosions might occur within Mayon’s six kilometer permanent danger zone.
As of August 12, the National Disaster Risk Reduction and Management Council (NDRRMC) said Mayon’s unrest have affected 38,396 people, including 20,254 displaced individuals.