Report on Pavlof (United States) — June 1976
Natural Science Event Bulletin, vol. 1, no. 9 (June 1976)
Managing Editor: David Squires
Pavlof (United States) Steam-and-ash emissions continue; ashfall on cone
Please cite this report as:
Global Volcanism Program, 1976. Report on Pavlof (United States). In: Squires, D (ed.), Natural Science Event Bulletin, 1:9. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.NSEB197606-312030.
55.417°N, 161.894°W; summit elev. 2493 m
All times are local (unless otherwise noted)
2 June, 1450: pilot reported volcano steaming, extensive ash deposits visible on top and E flank of cone. 3 June, 1200-1800: volcano quiet, cone darkened by ash, or exposed rock due to melted snow. 4 June, 0900-2100: steamed continuously; occasionally ejected a light tan ash that settled into a thin layer at the 2500-m level and moved NE up the Alaska Peninsula. 5 June, 1500-2200: no activity noted. 6 June 1810-1830: no activity noted.
10 June, 2100: black smoke and ash emitted. Flanks extensively darkened by ash. 11 June, 1500: pilot reported volcano steaming. 12 June, 0900-2100: no activity apparent. 15 June, 0600-0700, 2200: steaming constantly. 19 June, 1630: steaming and emitting grey smoke. 26 June, 1400-2100: vertical steam column reached 300-500 m above cone. 27 June, 1200-1500: intermittent steam and ash emissions formed a thin layer stretching NE at the 2500-m level. 28 June, 1300-2200: ash layer extended NE at the 2,500-m level.
Geologic Background. The most active volcano of the Aleutian arc, Pavlof is a 2519-m-high Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and its twin volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, Pavlof has been frequently active in historical time, typically producing Strombolian to Vulcanian explosive eruptions from the summit vents and occasional lava flows. The active vents lie near the summit on the north and east sides. The largest historical eruption took place in 1911, at the end of a 5-year-long eruptive episode, when a fissure opened on the N flank, ejecting large blocks and issuing lava flows.
Information Contacts: P. Sventek, USAF, Cold Bay.