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Suiyo Seamount

Stratovolcano in Japan

Key Facts

Elevation

-991 m (-3,251 ft)

Type

Stratovolcano

Location

28.575°, 140.633°

Region

Ogasawara Volcanic Arc

Rock Type

Andesite / Basaltic Andesite

Tectonic Setting

Subduction zone

Location

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Overview

Suiyo, one of the Shichiyo Seamounts, named for the seven days of the week, lies south of Sofugan volcano. Suiyo ("Wednesday") is a basaltic-to-dacitic submarine volcano and lava dome that rises about 1,400 m from the sea floor to within about 1,000 m of the surface. The summit crater is 1.

5 km wide and about 500 m deep. Major hydrothermal activity was observed in July 1991, with temperatures reaching more the 290°C, and the volcano was reclassified as active by the Japan Meteorological Agency.

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
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
Unrest / Holocene

Eruption Statistics & Analysis

MetricValueGlobal RankingSignificance
Total Recorded EruptionsUnknownLowModerately active volcano
Maximum VEIVEI UnknownMinorLocal impact potential
Recent ActivityUnknownHistoricalHistorically 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: 284093
  • Evidence: Unrest / Holocene
  • Epoch: Holocene

Basic Information

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