🌋VolcanoAtlas

Izu-Oshima

Tokyo's Volcanic Island Neighbor

Elevation

746 m

Last Eruption

1990

Type

Stratovolcano

Country

Japan

Location

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Volcanic Hazards & Risk Assessment

Primary Hazards

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

Risk Level

Population at RiskHigh
Infrastructure RiskHigh
Aviation RiskSignificant

Geological Composition & Structure

Rock Types

Primary
Unknown
Silica Content
Varied composition

Tectonic Setting

Unknown
Intraplate setting with hotspot or regional volcanic activity.

Age & Formation

Epoch
Unknown
Evidence
Unknown

Eruption Statistics & Analysis

MetricValueGlobal RankingSignificance
Total Recorded EruptionsUnknownLowModerately active volcano
Maximum VEIVEI UnknownMinorLocal impact potential
Recent Activity36 years agoRecentRecently 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

Watch
Dormant but monitored. Capable of renewed activity.

Authority Sources

Smithsonian GVP
Official volcano database
JMA Volcano Info
Japan Meteorological Agency

Related Volcanoes

All Japan Volcanoes
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Izu Islands, Northwestern Pacific
Regional volcanoes

Other Volcanoes in Japan

Interesting Facts

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The 1986 eruption produced lava fountains reaching 1,600 m (5,250 ft) high — among the tallest ever recorded at a Japanese volcano.

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Izu-Oshima has 108 recorded eruptions, making it one of the most frequently erupting volcanoes in the northwestern Pacific region.

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The entire population of the island — more than 12,000 people — was evacuated during the 1986 eruption, one of the largest volcanic evacuations in Japanese history.

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Despite being primarily basaltic (typically associated with gentle eruptions), Izu-Oshima has produced six VEI 4 explosions in the past 2,000 years.

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The volcano lies just 120 km south of central Tokyo, making it one of the closest active volcanoes to a megacity of over 14 million people.

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More than 40 parasitic cones and craters are distributed across the island along two parallel rift zones.

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Izu-Oshima is known as 'Camellia Island' (Tsubaki no Shima) for its three million camellia trees that bloom in the volcanic soil each winter.

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The 4-km-wide summit caldera was formed by repeated collapse events and is one of the most well-defined calderas in the Izu island chain.

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Over 600 years have passed since the last VEI 4 eruption in 1421 — significantly longer than the historical average interval of 100–300 years between major events.

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In October 2013, Typhoon Wipha triggered landslides on Izu-Oshima's volcanic slopes that killed 39 people, demonstrating that volcanic terrain is hazardous even between eruptions.

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Izu-Oshima's black volcanic sand landscape, the Ura-Sabaku, is one of the few desert-like environments in humid, subtropical Japan.

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The volcano was built over the remnants of three older, dissected stratovolcanoes whose eroded forms still influence the island's topography.

Frequently Asked Questions

Is Izu-Oshima an active volcano?
Yes, Izu-Oshima is classified as an active volcano by the Japan Meteorological Agency (JMA). It last erupted on October 4, 1990, producing a VEI 2 explosive event from the Miharayama summit crater. The volcano has 108 recorded eruptions spanning more than 10,000 years, with major VEI 3–4 events recurring at intervals of roughly 100–300 years. The JMA maintains continuous seismic, deformation, and gas monitoring on the island, and periodic deep earthquakes indicate that the magmatic system beneath the volcano remains active. Volcanologists consider a future eruption to be certain; the only uncertainties are its timing and magnitude.
When did Izu-Oshima last erupt?
Izu-Oshima's most recent eruption occurred on October 4, 1990, when a brief VEI 2 explosive event took place at the 1987 summit crater of Miharayama. This was a relatively minor event compared to the much larger November 1986 eruption (VEI 3), which produced lava fountains up to 1,600 m high and triggered the evacuation of more than 12,000 residents. The current repose period of more than 35 years is notable but not unprecedented — the volcano has experienced similar quiet intervals between active phases throughout its history.
How do you get to Izu-Oshima from Tokyo?
Izu-Oshima is one of Japan's most accessible volcanic islands. The fastest route is by high-speed jet ferry from Takeshiba Pier in Tokyo, which takes approximately 1 hour 45 minutes. A slower overnight ferry service is also available. Alternatively, short flights operate from Chofu Airport (about 25 minutes) and there are seasonal connections from other airports. Once on the island, rental cars, bicycles, and a local bus network provide transportation. The volcano's Miharayama crater is reached by a well-maintained hiking trail of about 45 minutes from the caldera rim car park.
What happened during the 1986 Izu-Oshima eruption?
The November 1986 eruption was one of the most dramatic volcanic events in modern Japanese history. On November 15, fissures opened on the Miharayama cone, producing lava fountains reaching 1,600 m high and a 16-km eruption column. On November 21, new fissure vents opened on the caldera floor and northwestern flank, bringing lava dangerously close to residential areas. Authorities ordered the complete evacuation of all 12,000+ island residents by ferry and helicopter. The evacuation was completed successfully with no casualties. Residents returned approximately one month later. The event was rated VEI 3 and fundamentally reshaped volcanic hazard planning for the island.
How tall is Izu-Oshima volcano?
Izu-Oshima's summit reaches 746 m (2,448 ft) above sea level at the caldera rim. However, the Miharayama central cone, which is the active volcanic vent, rises to approximately 700 m. The total height of the volcanic edifice from the seafloor of Sagami Bay is considerably greater, as the surrounding ocean reaches depths exceeding 1,000 m. The island extends roughly 11 × 13 km and covers an area of about 91 km², making it the largest of the Izu Islands.
Is Izu-Oshima dangerous?
Izu-Oshima presents a moderate to high volcanic hazard. Approximately 7,000 people live permanently on the island, and more than 120,000 tourists visit annually. The volcano has produced six VEI 4 eruptions in the past 2,000 years, and over 600 years have passed since the last such event — longer than the typical recurrence interval. Lava flows, tephra fall, and volcanic gas are the primary direct hazards. Additionally, the island's volcanic terrain is susceptible to catastrophic landslides during heavy rainfall, as demonstrated by the 2013 Typhoon Wipha disaster that killed 39 people. However, Japan's sophisticated monitoring and evacuation systems significantly mitigate the risk.
What type of volcano is Izu-Oshima?
Izu-Oshima is classified as a basaltic stratovolcano. Unlike most Japanese stratovolcanoes, which erupt andesitic to dacitic magma and tend toward explosive behavior, Izu-Oshima's dominant rock types are basalt and picro-basalt — relatively fluid magmas that typically produce lava flows and fire fountaining. However, the volcano has nonetheless generated powerful explosive eruptions (up to VEI 4) when gas accumulation in the magma chamber exceeded critical thresholds. The volcano features a 4-km-wide summit caldera containing the Miharayama central cone, plus more than 40 parasitic cones along two parallel rift zones.
Can you see Mount Fuji from Izu-Oshima?
Yes, on clear days Mount Fuji is visible from Izu-Oshima, particularly from the caldera rim and the summit area of Miharayama. The two volcanoes are separated by approximately 100 km of ocean and the Izu Peninsula. The best views are typically in winter, when cold, dry air provides maximum visibility. Seeing Japan's most iconic volcano from the caldera rim of an active volcano is one of the highlights of visiting Izu-Oshima. The Izu island chain and the mountainous coastline of the Izu Peninsula are also visible from the summit.