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Ibu

Stratovolcano in Indonesia

Last Eruption: 2025

Key Facts

Elevation

1,357 m (4,452 ft)

Type

Stratovolcano

Location

1.494°, 127.632°

Region

Halmahera Volcanic Arc

Total Eruptions

5

Max VEI

VEI 2

Rock Type

Andesite / Basaltic Andesite

Tectonic Setting

Subduction zone

Location

Loading map...

Eruption Timeline

2025 CENotable

Most recent confirmed eruption

2010 CEVEI 3

Historical eruption (estimated)

1990 CEVEI 3

Historical eruption (estimated)

1970 CEVEI 1

Historical eruption (estimated)

1950 CEVEI 1

Historical eruption (estimated)

Overview

The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, has contained several small crater lakes. The 1.

2-km-wide outer crater is breached on the N, creating a steep-walled valley. A large cone grew ENE of the summit, and a smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks.

The first observed and recorded eruption was a small explosion from the summit crater in 1911. Eruptive activity began again in December 1998, producing a lava dome that eventually covered much of the floor of the inner summit crater along with ongoing explosive ash emissions.

Volcanic Hazards & Risk Assessment

Primary Hazards

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

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 Eruptions5LowModerately active volcano
Maximum VEIVEI 2MinorLocal impact potential
Recent Activity1 years 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 Western Pacific Volcanic Regions

Regional Volcanic Activity
The Western Pacific 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: 268030
  • Evidence: Eruption Observed
  • Epoch: Holocene

About the Photo

Gunung Ibu volcano on the NW coast of Halmahera Island rises beyond a small village on its WNW flank. The summit of the stratovolcano is truncated by nested craters; the inner crater, 1 km wide and 400 m deep, contains several small crater lakes. The outer crater is breached on the north side, forming the deep valley seen here on the left side of the summit ridge. Few eruptions are known in historical time from Ibu, although it was erupting at the time of this February 1999 photo.

Photo by Agus Karim, 1999 (Volcanological Survey of Indonesia).

Basic Information

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