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VOLCANIC ACTIVITY REPORT: MAYON VOLCANO, ALBAY PROVINCE

1-10 June 2023       

 

 1) Summary of Activity:

The alert status of Mayon Volcano was raised to Alert Level 2 (Increasing Unrest) on 5 June 2023 following a sharp increase in the incidence of rockfall from its summit lava dome from an average of 5 events/day in May 2023 to 49 events/day on 5 June 2023. Pronounced increases in rockfall signify the extrusion of new lava beneath the summit lava dome, destabilizing this and causing its spalling or collapse. Rockfall activity increased while volcanic earthquake activity was absent to sparse, SO2 emissions were at background or baseline levels and short-term ground deformation consisted mainly of swelling of the middle to upper slopes of the edifice.  Extremely slow growth of Mayon’s lava dome was first detected by visual monitoring on 20 August 2022, warranting the raise to Alert Level 2 on 7 October 2022 that was stepped down to Alert Level 1 on 16 March 2023. Between August 2022 and May 2023, the summit lava dome grew by approximately 164,000 m3.

Days of increased incidence and volume of rockfall based on seismic records were followed by the generation of short pyroclastic density currents (PDCs) or “uson” in the morning of 8 June 2023. The PDCs were emplaced on the Bonga (Legaspi City), Miisi (Daraga) and Basud (Sto. Domingo) Gullies as far as two (2) kilometers from the summit crater. This indicated that new, less degassed lava was already being spalled from the summit dome and that eruption of very slowly extruding magma had slightly increased. Alert Level 3 (Increased Tendency Towards Hazardous Eruption) was raised on 12:00 noon of 8 June 2023. In the evening thereof, incandescent rockfall generated by intermittent collapse of an apparent fluidal lava portion of the summit dome were deposited on the above gullies within a kilometer of the crater. A new summit dome impinging a remnant on the southeast crater floor was observed in the early morning of 10 June. As of 7:00PM of 10 June 2023, a total of 654 rockfall events since 1 June and seven (7) PDCs have been recorded by the Mayon Volcano Network. Average SO2 flux increased beyond baseline levels today to 1,205 tonnes/day. All other monitoring parameters remain unchanged.

 

2) Current Outlook:

 

Ongoing slow extrusive eruption of new lava at the summit is currently accompanied by moderately elevated SO2 and low-level seismic and ground deformation parameters. This state of unrest may progress into the following eruption scenarios under various changes in monitored parameters:

a) Slow lava dome and short lava flow extrusion (e.g. 2014 eruption), if current rate of extrusion and low-level parameters persist. Activity may persist for a few months. Alert Level 3 is maintained.

b) Slow and sustained lava extrusion (e.g. 2006 eruption), if apparent rates of extrusion increase, SO2 emission increases persist and seismic activity (e.g. low-level tremor) and a cycle of inflation (swelling) and deflation (unswelling) of the edifice occur. Activity may last for a few months. Alert Level 4 will be raised.

c) Lava fountaining and lava flow with occasional explosions and PDCs within the 6km-PDZ (e.g. 2018 eruption), if significant increases in SO2 emission, increased seismicity (low-frequency and tremor events) and inflation (swelling) of the entire edifice occur. Activity may last for a few months. Alert Level 4 will be raised.

d) Explosive eruption with high-intensity lava fountaining, long lava flows and PDCs on all sectors that could exceed the 6km-PDZ (e.g. 2000 eruption), if rapid escalation in SO2 (or sudden drop), volcanic earthquake activity and ground deformation occur. Activity may last for a few days to weeks. Alert Level 5 will be raised.

 

3) Recommendations:

 

Evacuation of the Six-Kilometer Radius Permanent Danger Zone (PDZ) is recommended at Alert Level 3. The following barangays of Albay Province have portions that are located within the PDZ based on 2016 administrative boundary data from the PSA:

Barangay

City/Municipality

Barangay

City/Municipality

Oson

City Of Tabaco

Sua

Camalig

Mariroc

City Of Tabaco

Tumpa

Camalig

Comon

City Of Tabaco

Anoling

Camalig

Magapo

City Of Tabaco

Quirangay

Camalig

Buang

City Of Tabaco

Mi-isi

Daraga

San Roque

Malilipot

Doña Tomasa (Magatol)

Guinobatan

Calbayog

Malilipot

Muladbucad Pequeño

Guinobatan

Santa Cruz

 Malilipot

Muladbucad Grande

Guinobatan

Canaway

Malilipot

Masarawag

Guinobatan

Baligang

City of Ligao

Mabinit

Legaspi City

Fidel Surtida

Santo Domingo

Buyuan

Legaspi City

Lidong

Santo Domingo

Matanag

Legaspi City

San Fernando

Santo Domingo

Bonga

Legaspi City

Santa Misericordia

Santo Domingo

Padang

Legaspi City

 

 

Bonga (Upper)

Bacacay

 

DOST-PHIVOLCS