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Seamount X

Stratovolcano in United States

Key Facts

Elevation

-1,230 m (-4,035 ft)

Type

Stratovolcano

Location

13.250°, 144.020°

Region

Mariana Volcanic Arc

Rock Type

Basalt / Picro-Basalt

Tectonic Setting

Subduction zone

Location

Loading map...

Overview

Hydrothermal activity was detected during a 2003 NOAA expedition at a submarine volcano about 70 km WSW of Guam. The summit of the volcano, referred to as Seamount X, lies 1,230 m below the ocean surface. Diffuse sites of thermal venting colonized by shrimps, crabs, and scaleworms were detected near the summit during a 2006 NOAA expedition, and thick deposits of sulfur flows originating from the hydrothermal vent were observed that were covered with thousands of squat lobsters.

Basaltic rocks were recovered along with sulfur samples. The summit of the volcano is cut by an elongated caldera.

Volcanic Hazards & Risk Assessment

Primary Hazards

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

Risk Level

Population at RiskModerate
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
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

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: 284230
  • Evidence: Unrest / Holocene
  • Epoch: Holocene

About the Photo

A bathymetric map showing Seamount X was produced using data from 2004 and 2006 NOAA submarine vents expeditions. The seamount lies about 70 km WSW of Guam and displays areas of hydrothermal venting. The contour interval is 200 m.

Image courtesy of Susan Merle (Oregon State University/NOAA Vents Program).

Basic Information

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