Philippines

DSWD DROMIC Preparedness for Response Report #32 on the Mayon Volcano Seismic Activity as of 23 September 2022, 6AM

Attachments

I. Brief Background on Mayon Volcano

  • Mayon Volcano, called the world’s most perfect volcanic cone because of the symmetry of its shape, has a base 80 miles (130 km) in circumference and rises to 8,077 feet (2,462 meters) from the shores of Albay Gulf.

  • A highly active stratovolcano with recorded historical eruptions dating back to 1616. The most recent eruptive episode began in early January 2018 that consisted of phreatic explosions, steam-and-ash plumes, lava fountaining, and pyroclastic flows (BGVN 43:04). The previous report noted small but distinct thermal anomalies, gasand-steam plumes, and slight inflation (BGVN 44:05) that continued to occur from May into mid-October 2019.

  • Between May and October 2019, white gas-and-steam plumes rose to a maximum altitude of 800 m on 17 May 2019. The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported that faint summit incandescence was frequently observed at night from May-July and Sentinel-2 thermal satellite imagery showed weaker thermal anomalies in September and October; the last anomaly was identified on 12 October. Average sulfur dioxide (SO2) emissions as measured by PHIVOLCS generally varied between 469-774 tons/day; the high value of the period was on 25 July 2022 with 1,171 tons/day. Small SO2 plumes were detected by the TROPOMI satellite instrument a few times during May-September 2019.

II. Situation Overview

  • Mayon Volcano is at Alert Level 1, which means that it is at low-level volcanic unrest.

  • Alert Level 1 indicates slight increase in volcanic earthquake and steam/gas activity. Sporadic explosions from the summit crater or new vents. Notable increase in the temperature, acidity and volcanic gas concentrations of monitored springs and fumaroles. Slight inflation or swelling of the edifice.

  • This means that the volcano is exhibiting abnormal conditions and has entered a period of unrest. The public is reminded that entry into the 6-km Permanent Danger Zone or PDZ must be strictly avoided due to an increase in the chances of sudden steam-driven or phreatic eruption, as well as the perennial hazards of rockfalls, avalanches and ash bursts at the summit area, that may occur without warning. Furthermore, people living in valleys and active river channels are cautioned to remain vigilant against sediment-laden streamflows and lahars in the event of prolonged and heavy rainfall brought about by the advent of the rainy season.

  • Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ejecta from any sudden phreatic eruption can be hazardous to aircraft.

  • DOST-PHIVOLCS is closely monitoring Mayon Volcano’s activity and any new development will be relayed to all concerned.