Roundtop
Stratovolcano in United States
Key Facts
Elevation
1,871 m (6,138 ft)
Type
Stratovolcano
Location
54.800°, -163.589°
Region
Aleutian Ridge Volcanic Arc
Rock Type
Rhyolite
Tectonic Setting
Subduction zone
Location
Loading map...
Overview
The flat-topped, glacier-covered Roundtop is the easternmost and lowest of an E-W-trending line of volcanoes on eastern Unimak Island, 13 km SW of the village of False Pass. The snow and ice-covered edifice fills much of a 3-km-wide caldera that formed during the early Holocene. The caldera-forming eruption produced pyroclastic flows and a rhyolitic tephra layer that is widespread throughout the southwestern end of the Alaska Peninsula.
A group of lava domes was constructed south of the volcano. No historical eruptions are known, but in the 1930's warm springs were found on its slopes.
Volcanic Hazards & Risk Assessment
Primary Hazards
- Pyroclastic flows
- Lava flows
- Volcanic bombs and ballistics
- Lahars and mudflows
Risk Level
Geological Composition & Structure
Rock Types
Tectonic Setting
Age & Formation
Eruption Statistics & Analysis
| Metric | Value | Global Ranking | Significance |
|---|---|---|---|
| Total Recorded Eruptions | Unknown | Low | Moderately active volcano |
| Maximum VEI | VEI Unknown | Minor | Local impact potential |
| Recent Activity | 9626 years ago | Historical | Historically active |
Monitoring & Alert Status
Monitoring Networks
Current Status
Nearby Volcanoes in North America Volcanic Regions
Quick Info
- •Smithsonian ID: 311380
- •Evidence: Eruption Dated
- •Epoch: Holocene
About the Photo
Glacier-covered Roundtop volcano is seen here to the west of False Pass village, is the easternmost and lowest of an E-W-trending line of volcanoes on Unimak Island. Roundtop has produced Holocene pyroclastic flows, and a group of lava domes to the south.
Photo by Game McGimsey, 1998 (Alaska Volcano Observatory, U.S. Geological Survey).
Authority Sources
Related Volcanoes
Basic Information
This page shows basic data from the Smithsonian Global Volcanism Program. For more detailed information, visit the official Smithsonian page.