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Pavlof

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  • Country
  • Subregion Name
  • Volcano Type
  • Last Known Eruption
  • 2519 m
    8262 ft
  • 55.420°
  • -161.887°
  • Elevation
  •  
  • Latitude
  • Longitude

12 June-18 June 2013

AVO reported that ash emissions from Pavlof were intermittent and minor during 12-14 June; ash plumes below an altitude of 6.1 km (20,000 ft) a.s.l. mostly drifted SE. Elevated surface temperatures consistent with lava effusion persisted until 1620 on 14 June. Seismicity decreased during 14-15 June. Minor emissions likely stopped, but web-camera views were cloudy. On 17 June no plumes were visible in satellite images, and web camera views showed mostly cloudy conditions. During 17-18 June seismic tremor amplitude increased slightly, and elevated surface temperatures consistent with lava effusion were detected in satellite images. A small ash plume rose from the crater. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Sources: Alaska Volcano Observatory (AVO)



 Available Weekly Reports




2013: May | June |
2007: August | September |

12 June 2013              Back to Top

AVO reported that ash emissions from Pavlof were intermittent and minor during 12-14 June; ash plumes below an altitude of 6.1 km (20,000 ft) a.s.l. mostly drifted SE. Elevated surface temperatures consistent with lava effusion persisted until 1620 on 14 June. Seismicity decreased during 14-15 June. Minor emissions likely stopped, but web-camera views were cloudy. On 17 June no plumes were visible in satellite images, and web camera views showed mostly cloudy conditions. During 17-18 June seismic tremor amplitude increased slightly, and elevated surface temperatures consistent with lava effusion were detected in satellite images. A small ash plume rose from the crater. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Sources: Alaska Volcano Observatory (AVO)

5 June 2013              Back to Top

AVO reported that ash emissions from Pavlof that began on 4 June continued during 5-11 June, and were accompanied by seismic tremor and explosion signals. Overnight during 4-8 June satellite images detected elevated surface temperatures near the vent consistent with lava effusion and fountaining. On 5 and 6 June an ash plume observed in images drifted 40-45 km W and SW, at altitudes of 4.3-5.5 km (14,000-18,000 ft) a.s.l., based on pilot estimates. During 8-10 June images showed an ash plume drifting 20-53 km SE. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Sources: Alaska Volcano Observatory (AVO)

29 May 2013              Back to Top

AVO reported that ash emissions at Pavlof began at approximately 1100 on 4 June as observed in satellite images and by pilots. Satellite images showed an ash cloud drifting SE, and pilots estimated that the cloud was at an altitude of 5.8 km (19,000 ft) a.s.l. Weak seismicity that began at 1057 accompanied the emissions, and then continued. The Volcanic Alert Level was increased to Watch and the Aviation Color Code was increased Orange.

Sources: Alaska Volcano Observatory (AVO)

22 May 2013              Back to Top

AVO reported that seismic tremor at Pavlof markedly declined around 1100 on 21 May, and was followed through 23 May by the detection of small discrete events, likely indicative of small explosions, by pressure sensors. Although cloud cover prevented satellite observations, elevated surface temperatures at the vent were detected. On 22 May both a pilot report and photographs indicated weak steam-and-gas emissions containing little to no ash.

The eruption continued but at a lower level during 24-26 May. Neither evidence of elevated surface temperatures nor a plume were observed in partly clear satellite images during 24-25 and 27 May. Clouds obscured views on 26 May. The Volcanic Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow on 28 May.

Sources: Alaska Volcano Observatory (AVO)

15 May 2013              Back to Top

AVO reported that on 14 May a diffuse ash plume from Pavlof drifted about 160 km NE at an altitude of 4.6 km (15,000 ft) a.s.l. before dissipating. Pilot reports and photographs indicated that the lava flow extending down the NW flank was still active and generated debris-laden flow deposits, presumably from the interaction of hot lava with the snow and ice on the flank. Light ashfall was reported the evening of 14 May in a mining camp 80 km NE of the volcano. No other nearby communities had reported ash fall. During 14-15 May elevated seismicity persisted and steam-and-ash clouds observed with a web camera occasionally rose up to 6.1 km (20,000 ft) a.s.l. Residents in Cold Bay (37 km SW) observed incandescence from the summit during the night. On 15 May a pilot reported a dark ash cloud drifting ENE at an altitude of 6.1 km (20,000 ft) a.s.l.

On 16 May lava fountaining at the summit was observed and photographed, and a continuous ash, steam, and gas cloud extended downwind 50-100 km at an altitude of about 6.1 km (20,000 ft) a.s.l. Satellite images showed persistent elevated surface temperatures at the summit and on the NW flank, commensurate with the summit lava fountaining and resulting lava flow.

During 18-19 May a narrow plume of steam, ash, and gas, occasionally rising up to 6.7 km (22,000 ft) a.s.l., and drifting southeast, was visible in satellite images. Pilot reports indicated that lava fountaining and ash emission continued. Overnight, trace amounts of ash fell on the community of Sand Point. During the afternoon on 19 May pilots reported that ash plumes rose to altitudes of 4.6-6.7 km (15,000-22,000 ft) a.s.l. Trace amounts of ash fell in Nelson Lagoon, 78 km NNE, during 19-20 May. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

A news article stated that on 20 May a regional airline canceled about a dozen flights to several remote communities, including Sand Point. Another regional airline canceled a few flights, but mostly re-routed flights. On 21 May AVO reported that a low-level plume of steam, gas, and ash occasionally rose to an altitude of 6.1 km (20,000 ft) a.s.l. and drifted NNE. Trace amounts of ash again fell in Nelson Lagoon.

Sources: Alaska Volcano Observatory (AVO) , Associated Press

8 May 2013              Back to Top

AVO reported that on 13 May seismicity at Pavlof increased at 0800 commensurate with the presence of an intense thermal anomaly at the summit observed in satellite imagery. Several spikes in seismicity occurred between 0900 and 1000. AVO noted that similar patterns of seismicity and elevated surface temperatures have previously signaled the onset of eruptive activity at Pavlof. Although not yet visually confirmed at the time of the report, a low-level eruption of lava had likely begun from a summit vent. No ash clouds were detected. The Volcanic Alert Level was increased Watch and the Aviation Color Code was increased Orange. On 14 May pilot reports and satellite images confirmed activity; a spatter-fed lava flow advanced about 0.5 km down the N flank. Minor steam-and-ash emissions from the summit were visible from Cold Bay (60 km SW).

Sources: Alaska Volcano Observatory (AVO)

19 September 2007              Back to Top

On 19 September, a field crew confirmed that all eruptive activity from Pavlof ceased. AVO decreased the Volcanic Alert Level to Advisory and the Aviation Color Code to Yellow on 20 September due to a significant decrease of seismic activity during the previous week.

Sources: Alaska Volcano Observatory (AVO)

12 September 2007              Back to Top

AVO reported that seismic activity at Pavlof declined markedly during 8-18 September, compared to levels recorded during the first week of September. Seismicity was characterized by volcanic tremor, and signals interpreted as small explosions. Based on observations of satellite imagery, a steam plume rose to an altitude of 6.1 km (20,000 ft) a.s.l. on 12 September and multiple thermal anomalies were present during 12-14 September. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Sources: Alaska Volcano Observatory (AVO)

5 September 2007              Back to Top

Seismic activity at Pavlof fluctuated, but generally remained elevated during 5-11 September. Seismicity was characterized by volcanic tremor, and signals interpreted as frequent explosions and debris flows. During the reporting period, satellite imagery revealed strong thermal anomalies at the summit. On 8 September, a possible steam plume was visible on satellite imagery and a pilot reported that a steam-and-ash plume drifted from the summit. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Sources: Alaska Volcano Observatory (AVO)

29 August 2007              Back to Top

Seismic activity at Pavlof fluctuated, but generally remained elevated during 29 August-4 September. A strong thermal anomaly was present at the summit on satellite imagery during 29 August-2 September; clouds inhibited observations on 3 and 4 September. Based on pilot reports and observations of satellite imagery, ash plumes rose to altitudes of 2.4-4.9 km (8,000-16,000 ft) a.s.l. during 28-30 August and drifted SSE and SE. On 30 August, National Weather Service observers in Cold Bay (about 60 km SW) reported that a plume rose to an altitude of 6.1 km (20,000 ft) a.s.l. and produced lightning. Based on satellite imagery, AVO reported that steam-and-ash plumes rose to altitudes of 6.1 km (20,000 ft) a.s.l. on 31 August. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Sources: Alaska Volcano Observatory (AVO)

22 August 2007              Back to Top

Seismic activity at Pavlof remained elevated during 22-28 August. A strong thermal anomaly was present at the summit on satellite imagery on 22, 24, 25, and 28 August; clouds inhibited observations on other days. Based on pilot reports and calculations using satellite imagery, a steam-and-ash plume rose to an altitude between 3-5.5 km (10,000-18,000 ft) a.s.l. On 25 August, seismic events and explosions were more energetic and a signal suggesting a large lahar was noted. Plume altitudes from previous days and seismic interpretation indicated that an ash plume rose to an altitude of 6.1 km (20,000 ft) a.s.l. on 26 and 28 August. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Sources: Alaska Volcano Observatory (AVO)

15 August 2007              Back to Top

AVO raised the Volcanic Alert Level to Advisory and the Aviation Color Code to Yellow for Pavlof on 14 August due to an abrupt increase in seismicity. During 14-15 August, a strong thermal anomaly was detected in the crater and prompted AVO to again raise the Volcanic Alert Level/ Aviation Color Code, to Watch/Orange. According to eye witnesses aboard a ship on 15 August, incandescent blocks rolled down the ESE flank and lava-fountaining occurred on the SE flank. The presence of lava was confirmed using satellite imagery. Pilots reported that the flanks were covered with ash and that an ash plume rose to an altitude of 2.6 km (8,400 ft) a.s.l. and drifted SW.

On 16 August, residents of Cold Bay, about 60 km SW, and of Sand Point, about 97 km ESE, saw incandescence at the summit. A strong thermal anomaly was present at the summit on satellite imagery. Seismicity increased in intensity and possibly indicated a lahar on the SE flank.

During 17-20 August, seismicity continued at high levels. Explosions were recorded and seismic signals possibly indicated flow events such as lahars. A strong thermal anomaly continued to be present at the summit. Aerial and ground observations revealed a vigorous eruption of lava during 18-20 August. Members of an AVO field party saw a lahar on the SE flank on 20 August.

Sources: Alaska Volcano Observatory (AVO)



Summary of eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2007 Aug 15 2007 Sep 13 Confirmed 2 Historical
[ 2001 Jun 5 ± 4 days ] [ Unknown ] Uncertain 1  
1996 Sep 11 1997 Jan 3 (?) Confirmed 1 Historical
1990 Mar 5 1990 Mar 5 Confirmed 2 Historical
1986 Apr 16 1988 Aug 13 Confirmed 2 Historical NNE & SE summit vents, NE & SE flanks
1983 Nov 11 1983 Dec 18 Confirmed 2 Historical Upper NNE flank
1983 Jul 11 1983 Jul 18 Confirmed 2 Historical
[ 1982 Jul 15 ± 45 days ] [ Unknown ] Uncertain 1  
1981 Sep 25 1981 Sep 27 Confirmed 3 Historical Upper NNE flank (100 m below summit)
1981 Mar 30 (in or before) 1981 May 28 Confirmed 1 Historical
1980 Nov 8 1980 Nov 13 Confirmed 1 Historical Upper NNE flank
1980 Jul 6 ± 1 days Unknown Confirmed 1 Historical
1975 Sep 13 1977 Mar (in or after) Confirmed 2 Historical
1974 Sep 1 (in or before) 1975 Jan 13 Confirmed 2 Historical
1974 Mar 12 1974 Mar 24 (?) Confirmed 1 Historical
1973 Nov 12 1973 Nov 13 Confirmed 2 Historical Upper NE flank
1966 Mar 15 Unknown Confirmed 2 Historical Upper NE or NNE flank
1960 (?) 1963 Jun (?) Confirmed 2 Historical Upper NE or NNE flank
1958 May 17 1958 Aug 28 Confirmed 2 Historical Upper NNE flank
1953 Nov 25 1954 Aug Confirmed 1 Historical Upper NE or NNE flank
1951 Oct 1952 Feb (?) Confirmed 2 Historical Upper NE or NNE flank
1950 Jul 31 1951 May Confirmed 2 Historical Upper NE or NNE flank
1936 1948 May (?) Confirmed 2 Historical
1929 Mar 1931 Aug Confirmed 2 Historical
1924 Jan 17 Unknown Confirmed 2 Historical
1922 Dec 24 1923 Feb 28 ± 60 days Confirmed 2 Historical
1917 Oct Unknown Confirmed 2 Historical
1914 Jul 6 Unknown Confirmed 2 Historical
1906 1911 Dec 7 (?) Confirmed 2 Historical Summit and north flank fissure
1901 Unknown Confirmed 2 Historical
1894 Unknown Confirmed 2 Historical
1892 Unknown Confirmed 2 Historical
1886 Unknown Confirmed 2 Historical
1880 Unknown Confirmed 1 Historical
1866 Mar 14 Unknown Confirmed 2 Historical
[ 1852 ] [ Unknown ] Uncertain 1   Upper north flank
1846 Aug 1846 Aug Confirmed 2 Historical
1845 Aug 12 Unknown Confirmed 2 Historical
1838 Unknown Confirmed 1 Historical
1825 Unknown Confirmed 2 Historical
1817 Unknown Confirmed 2 Historical
1790 Unknown Confirmed 2 Historical
1762 1786 Confirmed 1 Unknown

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 of Pavlof took place in 1911, at the end of a 5-year-long eruptive episode. During this eruption a fissure opened on the northern flank of the volcano, ejecting large blocks and issuing lava flows.