Pavlof Sister

Photo of this volcano
Google Earth icon
  Google Earth Placemark
  • United States
  • Alaska
  • Stratovolcano
  • Unknown - Evidence Credible
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 55.457°N
  • 161.854°W

  • 2142 m
    7026 ft

  • 312040
  • Latitude
  • Longitude

  • Summit

  • Volcano

The Global Volcanism Program has no activity reports for Pavlof Sister.

The Global Volcanism Program has no Weekly Reports available for Pavlof Sister.

The Global Volcanism Program has no Bulletin Reports available for Pavlof Sister.

Basic Data

Volcano Number

Last Known Eruption



Unknown - Evidence Credible

2142 m / 7026 ft


Volcano Types


Rock Types

Basalt / Picro-Basalt

Tectonic Setting

Subduction zone
Continental crust (> 25 km)


Within 5 km
Within 10 km
Within 30 km
Within 100 km

Geological Summary

Located at the end of a chain of volcanoes trending NE from Emmons Lake caldera, the symmetrical Pavlof Sister stratovolcano is somewhat more eroded than its twin volcano to the SW, Pavlof. Pavlof Sister, along with Pavlof and Little Pavlof is a stratovolcano that formed outside of the Emmons Lake caldera; these and other volcanoes inside Emmons Lake caldera are not glaciated and thus would have formed since the area was last glaciated about 15-20,000 years ago. The 2142-m-high volcano is almost 400 m lower than Pavlof and has a sharper-peaked summit. Some sources attributed a period of intermittent eruptive activity from 1762 to 1786 CE to Pavlof Sister, but other sources consider this event to have been from Pavlof volcano. The two symmetrical volcanoes form a dramatic backdrop to Pavlof Bay and Volcano Bay near the western end of the Alaska Peninsula.


The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

Coats R R, 1950. Volcanic activity in the Aleutian Arc. U S Geol Surv Bull, 974-B: 35-47.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

Kennedy G C, Waldron H H, 1955. Geology of Pavlof volcano and vicinity Alaska. U S Geol Surv Bull, 1028-A: 1-18.

Motyka R J, Liss S A, Nye C J, Moorman M A, 1993. Geothermal resources of the Aleutian arc. Alaska Div Geol Geophys Surv, Prof Rpt, no 114, 17 p and 4 map sheets.

Smith R L, Shaw H R, Luedke R G, Russell S L, 1978. Comprehensive tables giving physical data and thermal energy estimates for young igneous systems of the United States. U S Geol Surv Open-File Rpt, 78-925: 1-25.

Waythomas C F, Miller T P, Mangan M T, 2006. Preliminary volcano hazard assessment for the Emmons Lake volcanic center, Alaska. U S Geol Surv, Sci Invest Rpt, 2006-5248: 1-33.

The Global Volcanism Program is not aware of any Holocene eruptions from Pavlof Sister. If this volcano has had large eruptions (VEI >= 4) prior to 10,000 years ago, information might be found on the Pavlof Sister page in the LaMEVE (Large Magnitude Explosive Volcanic Eruptions) database, a part of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).

The Global Volcanism Program has no synonyms or subfeatures listed for Pavlof Sister.

Photo Gallery

An ash plume trails to the south in mid-July 1986, 3 months after the start of an eruption of Pavlof that lasted nearly 2 1/2 years. This photo was taken from the west on a fishing boat in Pavlof Bay, with Pavlof Sister to the right. The 1986-88 eruption produced intermittent ashfalls and lava flows from two vents near the summit, one halfway down the SE flank, and another 600 m below the summit on the NE flank. Lava flows traveled to the north, NE, SE, ESE, and SSE, the latter to within 600 m of the Pavlof Bay shoreline.

Photo by Richard Mack, 1986.
The twin volcanoes of Pavlof (left) and Pavlof Sister (right) rise to 2519 m and 2142 m, respectively. This January 20, 1987, view from the SW shows steam clouds rising along the length of a lava flow descending a prominent gully on the SE (right-hand) flank of Pavlof volcano. Recent snowfall covers ashfall that frequently dusted its slopes. This eruption began with explosive activity on April 16, 1986, and continued until August 13, 1988. Lava flows traveled down the north, NE, SE, ESE, and SSE flanks, the latter reaching to within 600 m of Pavlof Bay.

Photo by Jerry Chisum (Mark Air), 1987 (courtesy of John Reeder, Alaska Div. Geology Geophysical Surveys).
The summits of the twin volcanoes of Pavlof Sister (left) and Pavlof (right) rise to 2142 m and 2519 m, respectively, above a low, roughly 1100-m-high saddle. They are viewed here in 1975 from lowlands to the NW. The somewhat less eroded Pavlof volcano, its slopes darkened by recent ashfalls, has been the source of frequent eruptions in historical time. Little Pavlof, a small satellitic volcano on the right flank of Pavlof, was also constructed along a line of vents trending NE from Emmons Lake caldera.

Photo by Tom Miller, 1975 (U.S. Geological Survey, Alaska Volcano Observatory).
Pavlof volcano, rising above low plains to its NW, is one of Alaska's most active volcanoes. It is part of a NNE-SSW-trending line of volcanoes near the tip of the Alaskan Peninsula. The knob on the middle right horizon is Little Pavlof, a subsidiary peak of Pavlof. The low saddle at the left separates Pavlof from Pavlof Sister, whose lower flanks are seen at the extreme left.

Photo by Steve McNutt, 1979 (University of Alaska, Alaska Volcano Observatory).
A small puff of dark ash rises from the summit crater of Pavlof volcano on May 28, 1960, as the detached plume from an earlier explosion drifts away to the east. Ash blankets the slopes of Pavlof in this view from the north. Mild ash eruptions took place from Pavlof from about 1960 to 1963, especially during July 1962 to June 1963. The sharp-topped peak at the left is snow-covered Pavlof Sister volcano, and Little Pavlof forms the smaller peak to the right of Pavlof.

Photo by Ken Morin, 1960 (courtesy of Bill Rose, Michigan Technological University).

Smithsonian Sample Collections Database

There are no samples for Pavlof Sister in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

Affiliated Sites

Large Eruptions of Pavlof Sister Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
WOVOdat WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
EarthChem EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).
MODVOLC - HIGP MODIS Thermal Alert System Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales.
MIROVA Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity.