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Tofua

Caldera in Tonga

Last Eruption: 2025

Key Facts

Elevation

515 m (1,690 ft)

Type

Caldera

Location

-19.750°, -175.070°

Region

Tofua Volcanic Arc

Total Eruptions

11

Max VEI

VEI Unknown

Rock Type

Andesite / Basaltic Andesite

Tectonic Setting

Subduction zone

Location

Loading map...

Eruption Timeline

2025 CENotable

Most recent confirmed eruption

1995 CEVEI 1

Historical eruption (estimated)

1975 CEVEI 3

Historical eruption (estimated)

1945 CEVEI 3

Historical eruption (estimated)

1940 CEVEI 3

Historical eruption (estimated)

1933 CEVEI 1

Historical eruption (estimated)

1926 CEVEI 3

Historical eruption (estimated)

1911 CEVEI 3

Historical eruption (estimated)

1886 CEVEI 2

Historical eruption (estimated)

1884 CEVEI 2

Historical eruption (estimated)

1872 CEVEI 3

Historical eruption (estimated)

Overview

The low, forested Tofua Island in the central part of the Tonga Islands group is the emergent summit of a large stratovolcano that was seen in eruption by Captain Cook in 1774. The summit contains a 5-km-wide caldera whose walls drop steeply about 500 m. Three post-caldera cones were constructed at the northern end of a cold fresh-water caldera lake, whose surface lies only 30 m above sea level.

The easternmost cone has three craters and produced young basaltic andesite lava flows, some of which traveled into the caldera lake. The largest and northernmost of the cones, Lofia, has a steep-sided crater that is 70 m wide and 120 m deep and has been the source of historical eruptions, first reported in the 18th century. The fumarolically active crater of Lofia has a flat floor formed by a ponded lava flow.

Volcanic Hazards & Risk Assessment

Primary Hazards

  • Pyroclastic flows and surges
  • Large explosive eruptions (VEI 4+)
  • Ash fall and tephra deposits
  • Lahars and debris flows

Risk Level

Population at RiskModerate
Infrastructure RiskHigh
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
Eruption Observed

Eruption Statistics & Analysis

MetricValueGlobal RankingSignificance
Total Recorded Eruptions11ModerateModerately active volcano
Maximum VEIVEI UnknownMinorLocal impact potential
Recent Activity1 year agoVery RecentCurrently active

Monitoring & Alert Status

Monitoring Networks

Global Volcanism Program
International eruption database

Current Status

Active
Recent volcanic activity detected. Continuous monitoring in place.

Nearby Volcanoes in Tonga-Kermadec Volcanic Regions

Regional Volcanic Activity
The Tonga-Kermadec 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: 243060
  • Evidence: Eruption Observed
  • Epoch: Holocene

About the Photo

A small plume rises from Lofia cone on the N side of the caldera lake of Tofua volcano in this 1990 aerial photograph. Recent tephra was emplaced onto the caldera rim to the NW. The steep walls of the 5-km-wide caldera are about 500 m high. Three post-caldera cones were constructed at the N end of a cold fresh-water caldera lake, whose surface lies only 30 m above sea level.

Aerial photo by Tonga Ministry of Lands, Survey, and Natural Resources, 1990 (published in Taylor and Ewart, 1997).

Basic Information

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