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Pavlof Sister

Stratovolcano in United States

Key Facts

Elevation

2,142 m (7,028 ft)

Type

Stratovolcano

Location

55.457°, -161.854°

Region

Aleutian Ridge Volcanic Arc

Rock Type

Basalt / Picro-Basalt

Tectonic Setting

Subduction zone

Location

Loading map...

Overview

Located near the western end of the Alaska Peninsula at the end of a chain of volcanoes trending NE from Emmons Lake caldera, the symmetrical Pavlof Sister stratovolcano is somewhat more eroded than Pavlof volcano to the SW. Pavlof Sister, along with Pavlof and Little Pavlof, 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. Pavlof Sister 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.

Volcanic Hazards & Risk Assessment

Primary Hazards

  • Pyroclastic flows
  • Lava flows
  • Volcanic bombs and ballistics
  • Lahars and mudflows

Risk Level

Population at RiskModerate
Infrastructure RiskModerate
Aviation RiskSignificant

Geological Composition & Structure

Rock Types

Primary
Basalt / Picro-Basalt
Silica Content
Low (45-52% SiO₂)

Tectonic Setting

Subduction zone
Formed by oceanic plate subduction, typically producing explosive eruptions due to water-rich magmas.

Age & Formation

Epoch
Holocene
Evidence
Evidence Credible

Eruption Statistics & Analysis

MetricValueGlobal RankingSignificance
Total Recorded EruptionsUnknownLowModerately active volcano
Maximum VEIVEI UnknownMinorLocal impact potential
Recent ActivityUnknownHistoricalHistorically active

Monitoring & Alert Status

Monitoring Networks

Global Volcanism Program
International eruption database

Current Status

Normal
No recent activity. Routine monitoring continues.

Nearby Volcanoes in North America Volcanic Regions

Regional Volcanic Activity
The North America Volcanic Regions contains multiple active volcanic systems. Cross-regional magma interactions and tectonic stresses can influence eruption patterns across the entire arc. Monitor regional seismic activity and volcanic alerts.

Quick Info

  • Smithsonian ID: 312040
  • Evidence: Evidence Credible
  • Epoch: Holocene

About the Photo

The summits of Pavlof Sister (left) and Pavlof (right) rise above a roughly 1,100-m-elevation saddle. They are viewed here in 1975 from lowlands to the NW. Pavlof is darkened by recent ash deposition and has been the source of frequent eruptions in historical time. Little Pavlof, a cone 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 (Alaska Volcano Observatory, U.S. Geological Survey).

Basic Information

This page shows basic data from the Smithsonian Global Volcanism Program. For more detailed information, visit the official Smithsonian page.