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Mikurajima

Stratovolcano in Japan

Last Eruption: -4100

Key Facts

Elevation

851 m (2,792 ft)

Type

Stratovolcano

Location

33.874°, 139.602°

Region

Izu Volcanic Arc

Rock Type

Basalt / Picro-Basalt

Tectonic Setting

Subduction zone

Location

Loading map...

Overview

Mikurajima is a small steep-sided island located between the more well-known Miyakejima and Hachijojima volcanoes. Oyama forms the summit of the basaltic-to-andesitic island, which is surrounded by cliffs and dissected on the southern-to-eastern sides. The sparsely populated island consists of a large stratovolcano with lava domes on the SE side.

Several small sea stacks are located immediately offshore. Growth of the stratovolcano took place until about 7,000 years ago, and the latest activity occurred about 6,000 years ago, when explosive eruptions and pyroclastic surges accompanied lava dome growth.

Volcanic Hazards & Risk Assessment

Primary Hazards

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

Risk Level

Population at RiskHigh
Infrastructure RiskModerate
Aviation RiskSignificant

Geological Composition & Structure

Rock Types

Primary
Basalt / Picro-Basalt
Silica Content
Low (45-52% 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 Dated

Eruption Statistics & Analysis

MetricValueGlobal RankingSignificance
Total Recorded EruptionsUnknownLowModerately active volcano
Maximum VEIVEI UnknownMinorLocal impact potential
Recent Activity6126 years agoHistoricalHistorically 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

Normal
No recent activity. Routine monitoring continues.

Nearby Volcanoes in Northwestern Pacific Volcanic Regions

Regional Volcanic Activity
The Northwestern 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: 284041
  • Evidence: Eruption Dated
  • Epoch: Holocene

About the Photo

The southern flanks of Mikurajima volcano are seen in this aerial view from the SSW. Oyama, the summit of the island, lies in shadow on the left horizon. The small Ichinomori spire is on the center, while the flat-topped Shipunegamori lava dome is at the far right.

Copyrighted photo by Akira Takada (Japanese Quaternary Volcanoes database, RIODB, http://riodb02.ibase.aist.go.jp/strata/VOL_JP/EN/index.htm and Geol Surv Japan, AIST, http://www.gsj.jp/).

Basic Information

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