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Suwanosejima

Stratovolcano(es) in Japan

Last Eruption: 2025

Key Facts

Elevation

796 m (2,612 ft)

Type

Stratovolcano(es)

Location

29.638°, 129.714°

Region

Ryukyu Volcanic Arc

Total Eruptions

24

Max VEI

VEI 4

Rock Type

Andesite / Basaltic Andesite

Tectonic Setting

Subduction zone

Location

Loading map...

Eruption Timeline

2025 CENotable

Most recent confirmed eruption

2000 CEVEI 3

Historical eruption (estimated)

1988 CEVEI 1

Historical eruption (estimated)

1986 CEVEI 3

Historical eruption (estimated)

1976 CEVEI 1

Historical eruption (estimated)

1961 CEVEI 3

Historical eruption (estimated)

1954 CEVEI 1

Historical eruption (estimated)

1947 CEVEI 3

Historical eruption (estimated)

1922 CEVEI 1

Historical eruption (estimated)

1919 CEVEI 3

Historical eruption (estimated)

1889 CEVEI 2

Historical eruption (estimated)

1884 CEVEI 3

Historical eruption (estimated)

1874 CEVEI 3

Historical eruption (estimated)

1844 CEVEI 3

Historical eruption (estimated)

1814 CEVEI 2

Historical eruption (estimated)

1812 CEVEI 2

Historical eruption (estimated)

1807 CEVEI 3

Historical eruption (estimated)

Overview

The 8-km-long island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two active summit craters. The summit is truncated by a large breached crater extending to the sea on the E flank that was formed by edifice collapse. One of Japan's most frequently active volcanoes, it was in a state of intermittent Strombolian activity from Otake, the NE summit crater, between 1949 and 1996, after which periods of inactivity lengthened.

The largest recorded eruption took place in 1813-14, when thick scoria deposits covered residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed, forming a large debris avalanche and creating an open collapse scarp extending to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption.

Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island.

Volcanic Hazards & Risk Assessment

Primary Hazards

    Risk Level

    Population at RiskHigh
    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 Eruptions24HighHighly active volcano
    Maximum VEIVEI 4MajorRegional impact potential
    Recent Activity1 years agoVery RecentCurrently active

    Monitoring & Alert Status

    Monitoring Networks

    Japan Meteorological Agency (JMA)
    Real-time seismic monitoring
    Geological Survey of Japan
    Geochemical monitoring
    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: 282030
    • Evidence: Eruption Observed
    • Epoch: Holocene

    About the Photo

    A plume rises above Ontake, the summit crater of Suwanosejima. The 8-km-long island consists of a stratovolcano with two historically active summit craters. The dipping scarp at the top of the image opens towards the sea on the E flank and formed by edifice collapse. This is one of Japan's most frequently active volcanoes and has been in a state of intermittent Strombolian activity since 1949.

    Photo by Yukio Hayakawa, 1998 (Gunma University).

    Basic Information

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