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Herbert

Stratovolcano in United States

Key Facts

Elevation

1,280 m (4,199 ft)

Type

Stratovolcano

Location

52.742°, -170.111°

Region

Aleutian Ridge Volcanic Arc

Rock Type

Andesite / Basaltic Andesite

Tectonic Setting

Subduction zone

Location

Loading map...

Overview

The 10-km-wide Herbert Island, the SW-most of the Islands of the Four Mountains group, lies across a strait SW of Mount Cleveland. This symmetrical stratovolcano has a summit truncated by a 2-km-wide caldera breached to NW. No historical eruptions have been recorded, and no geological studies have been published.

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
Andesite / Basaltic Andesite
Silica Content
Intermediate (57-63% 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: 311220
  • Evidence: Evidence Credible
  • Epoch: Holocene

About the Photo

Herbert is a cone containing a 2-km-wide summit caldera that opens to NW. This 23 June 1987 view from the WSW shows a small plume originating from Cleveland in background, with darkened slopes from ashfall produced during an eruption that began on 19 June.

Photo by Harold Wilson (Peninsula Airways), 1987 (courtesy of John Reeder, Alaska Div. Geology Geophysical Surveys).

Basic Information

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