🌋VolcanoAtlas

Miyakejima

Tokyo's Volatile Volcanic Island

Elevation

775 m

Last Eruption

2010

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

Basalt, Picro-Basalt

Tectonic Setting

Subduction zone — Pacific Plate beneath Philippine Sea Plate (oceanic crust < 15 km)
Formed by oceanic plate subduction, typically producing explosive eruptions due to water-rich magmas.

Age & Formation

Geological age and formation data
View detailed geological information →

Eruption Statistics & Analysis

MetricValueGlobal RankingSignificance
Total Recorded Eruptions40HighHighly active volcano
Maximum VEI4 (6450 BCE, 2900 BCE, 950 BCE, 260 CE, 850 CE, 1763 CE)MajorRegional impact potential
Recent Activity16 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

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Interesting Facts

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The 2000 eruption forced the complete evacuation of all 3,800 residents for nearly 5 years — one of the longest volcanic evacuations in modern Japanese history.

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At its peak, the 2000 caldera emitted approximately 50,000 tonnes of sulfur dioxide per day, making it one of the strongest volcanic gas sources on Earth.

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Miyakejima residents still carry portable gas masks at all times as a precaution against toxic sulfur dioxide emissions from the 2000 caldera.

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Despite being 200 km from downtown Tokyo, Miyakejima is administratively part of Tokyo Prefecture and governed by the Tokyo Metropolitan Government.

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The 1983 eruption destroyed approximately 400 buildings in Ako village when lava flows from a 4.5 km fissure reached the southwest coast.

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The 1.6 km wide summit caldera created in 2000 was formed not by explosion but by gradual subsidence as magma drained laterally through underground conduits.

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Miyakejima has erupted roughly every 20–60 years since 1469, creating a predictable but dangerous cycle for island residents.

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The island's volcanic gas crisis generated one of the world's most sophisticated real-time gas monitoring and public alert systems.

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A growing turquoise-colored acidic lake in the 2000 caldera raises new concerns about future phreatic explosions.

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Miyakejima is home to the endangered Izu thrush (Turdus celaenops), one of Japan's rarest songbirds, which has adapted to the volcanic landscape.

Frequently Asked Questions

Is Miyakejima safe to visit?
Miyakejima is open to visitors, though volcanic hazards require awareness. Residents and tourists must carry portable gas masks, as sulfur dioxide concentrations can spike in certain areas. Some parts of the island near the summit remain in high-gas restriction zones. JMA monitors the volcano continuously, and the island has an extensive gas alert system. Ferry and air services from Tokyo operate regularly. Guided volcano tours, hiking, diving, and birdwatching are popular activities.
What happened during the 2000 Miyakejima eruption?
The 2000 eruption began in late June with seismic unrest and evolved into a complex event. Submarine eruptions occurred off the western flank, followed by summit explosions and gradual caldera subsidence. A 1.6 km wide caldera formed as magma drained laterally, and explosive eruptions sent ash columns above 15 km altitude. All 3,800 residents were evacuated by September 2000. Massive sulfur dioxide emissions then prevented return until February 2005. It was one of Japan's most significant volcanic crises of the modern era.
Why do residents need gas masks on Miyakejima?
Following the 2000 eruption, the newly formed summit caldera began emitting enormous quantities of sulfur dioxide, peaking at 50,000 tonnes per day. Although emissions have declined significantly, SO2 concentrations still occasionally reach dangerous levels, particularly in low-lying areas during calm atmospheric conditions. An island-wide monitoring system tracks gas levels in real time, and alarms sound when concentrations exceed safety thresholds. Residents carry masks as a precaution against sudden gas concentration spikes.
How do you get to Miyakejima from Tokyo?
Miyakejima is accessible from Tokyo by overnight ferry (approximately 6 hours from Takeshiba Pier in central Tokyo) or by small aircraft from Chofu Airport in western Tokyo (approximately 50 minutes). The island has a small airport and a port facility. Ferry services run regularly but can be canceled in rough weather. The island is administratively part of Tokyo Prefecture despite being approximately 200 km to the south-southwest.
When will Miyakejima erupt again?
The exact timing cannot be predicted, but Miyakejima's historical eruption pattern — roughly every 20–60 years since 1469 — suggests another eruption is possible within the coming decades. The most recent eruption was in 2010 (minor, VEI 1), and major eruptions occurred in 1983 and 2000. JMA monitors the volcano continuously for precursory signs including increased seismicity, ground deformation, and changes in gas emissions.
How big is Miyakejima island?
Miyakejima is a nearly circular island approximately 8 km in diameter, covering about 55 km² (roughly 21 square miles). The summit of the volcano, Oyama, reaches 775 m (2,543 ft) above sea level, though the total edifice rises approximately 1,100 m from the seafloor. Approximately 2,500 people live in communities around the island's coast, primarily engaged in fishing, agriculture, and tourism.