Report on Mayon (Philippines) — November 1988
Scientific Event Alert Network Bulletin, vol. 13, no. 11 (November 1988)
Managing Editor: Lindsay McClelland.
Mayon (Philippines) Crater glow and steam emissions continue; mudflow damage
Please cite this report as:
Global Volcanism Program, 1988. Report on Mayon (Philippines) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 13:11. Smithsonian Institution.
13.257°N, 123.685°E; summit elev. 2462 m
All times are local (unless otherwise noted)
Faint crater glow continued to be observed during nights with good visibility in October and November. Moderate steam emission covered 30-50% of the crater and blue volcanic fumes sometimes moved slowly downslope.
In October and November, 77 high-frequency events, 59 low-frequency events, and 119 harmonic tremor episodes were recorded. Mudflows were detected (by seismographs and by a lahar mapping team) along the SE slopes on 12 and 23 October, and along the SE and SW slopes on 4, 6, 20, and 21 November. The 12 October lahar moved at 2.5 m/s down Basud gully between 2347 and 0141 the next morning. On the 23rd, three lahars with velocities of about 3.2 m/s were triggered by a typhoon. The Basud River was incised by 4 m (near the Lidong-Basud boundary), and a jeep caught by a flow surge along the river was partially buried by debris. Continuous undercutting caused 3-4 m of a cement road to collapse and a house was carried away by a flow. No casualties were reported.
Geological Summary. Beautifully symmetrical Mayon, which rises above the Albay Gulf NW of Legazpi City, is the Philippines' most active volcano. The structurally simple edifice has steep upper slopes averaging 35-40 degrees that are capped by a small summit crater. Historical eruptions date back to 1616 and range from Strombolian to basaltic Plinian, with cyclical activity beginning with basaltic eruptions, followed by longer term andesitic lava flows. Eruptions occur predominately from the central conduit and have also produced lava flows that travel far down the flanks. Pyroclastic flows and mudflows have commonly swept down many of the approximately 40 ravines that radiate from the summit and have often devastated populated lowland areas. A violent eruption in 1814 killed more than 1,200 people and devastated several towns.
Information Contacts: PHIVOLCS.