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Ascension

Stratovolcano in United Kingdom

Last Eruption: 1508

Key Facts

Elevation

822 m (2,697 ft)

Type

Stratovolcano

Location

-7.946°, -14.367°

Region

Central Mid-Atlantic Rift Volcanic Province

Rock Type

Basalt / Picro-Basalt

Tectonic Setting

Rift zone

Location

Loading map...

Overview

Ascensión Island, just west of the Mid-Atlantic Ridge ~2,250 km E of the eastern-most point of Brazil, is the 12-km-diameter emergent summit of a stratovolcano that rises ~3,000 m above the seafloor. The isolated island has more than 100 youthful cones and lava domes, many aligned along two fissures. Basaltic rocks dominate on the island, but trachytic lava domes are also present, mostly on the eastern side.

Two of the youngest lava flows were erupted from flank vents and reached the sea on the N and S coasts. Argon-Argon dating by Preece and others (2018) identified three eruptions within the past 2,000 years. No eruptive activity has occurred since it was visited on Ascensión Day in 1501 by the Portuguese navigator Joao da Nova.

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

Rift zone
Continental rift or intraplate setting with varied eruptive styles.

Age & Formation

Epoch
Holocene
Evidence
Eruption Dated

Eruption Statistics & Analysis

MetricValueGlobal RankingSignificance
Total Recorded EruptionsUnknownLowModerately active volcano
Maximum VEIVEI UnknownMinorLocal impact potential
Recent Activity518 years agoHistoricalHistorically active

Monitoring & Alert Status

Monitoring Networks

Global Volcanism Program
International eruption database

Current Status

Normal
No recent activity. Routine monitoring continues.

Nearby Volcanoes in Atlantic Ocean Volcanic Regions

Regional Volcanic Activity
The Atlantic Ocean 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: 385050
  • Evidence: Eruption Dated
  • Epoch: Holocene

About the Photo

A view to the NW from Green Mountain shows The Sisters (left) and Perfect Crater (right-center), cinder cones on the flanks of the Ascensión Island volcano, which lies just west of the Mid-Atlantic Ridge. The isolated island contains numerous cones and lava domes. Many volcanic features on Ascensión have a very youthful appearance, and three eruptions have been dated within the past 2,000 years, the most recent being the South Sisters flow, possibly only 500 years old.

Photo by Jon Davidson (University of Durham).

Basic Information

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