Report on Pinatubo (Philippines) — February 1992
Bulletin of the Global Volcanism Network, vol. 17, no. 2 (February 1992)
Managing Editor: Lindsay McClelland.
Pinatubo (Philippines) Vapor emission and low-level seismicity; small lahars
Please cite this report as:
Global Volcanism Program, 1992. Report on Pinatubo (Philippines) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 17:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199202-273083
15.13°N, 120.35°E; summit elev. 1486 m
All times are local (unless otherwise noted)
Two small lahars took place as a result of light rain showers in the Sacobia River drainage in late February, and steam emission continued through early March from a linear trend of fumaroles along the S edge of the 1991 caldera floor. Discrete larger emission episodes were occasionally observed, but there have been no confirmed ash emissions. Weak seismicity has continued at the volcano, including low-amplitude, low-frequency events, at least one of which corresponded with an observed steam emission.
Geological Summary. Prior to 1991 Pinatubo volcano was a relatively unknown, heavily forested lava dome complex located 100 km NW of Manila with no records of historical eruptions. The 1991 eruption, one of the world's largest of the 20th century, ejected massive amounts of tephra and produced voluminous pyroclastic flows, forming a small, 2.5-km-wide summit caldera whose floor is now covered by a lake. Caldera formation lowered the height of the summit by more than 300 m. Although the eruption caused hundreds of fatalities and major damage with severe social and economic impact, successful monitoring efforts greatly reduced the number of fatalities. Widespread lahars that redistributed products of the 1991 eruption have continued to cause severe disruption. Previous major eruptive periods, interrupted by lengthy quiescent periods, have produced pyroclastic flows and lahars that were even more extensive than in 1991.
Information Contacts: R. Punongbayan, PHIVOLCS.