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Dawson Strait Group

Volcanic field in Papua New Guinea

Last Eruption: 1350

Key Facts

Elevation

500 m (1,640 ft)

Type

Volcanic field

Location

-9.620°, 150.880°

Region

Trobriand Volcanic Province

Rock Type

Rhyolite

Tectonic Setting

Subduction zone

Location

Loading map...

Overview

The Dawson Straits, located between eastern Fergusson and western Normanby Islands in the D'Entrecasteaux island group, contains a volcanic field with several centers that define a possible partly submerged caldera. There have been no historical eruptions, but morphology suggests an extremely young age for some lava flows, and the area displays vigorous thermal activity. The most prominent volcanic centers are Mounts Lamonai and Oiau, located about 10 km apart on the SW tip of Fergusson Island.

The summit of Lamonai is capped by a steep-walled crater, and rhyolitic lava flows are exposed on the NE side of the cone. The dominantly volcaniclastic Oiau cone has also produced obsidian lava flows. Dobu Island to the south is formed of coalescing volcanic centers and likewise has produced youthful rhyolitic obsidian flows.

Volcanic Hazards & Risk Assessment

Primary Hazards

    Risk Level

    Population at RiskModerate
    Infrastructure RiskModerate
    Aviation RiskSignificant

    Geological Composition & Structure

    Rock Types

    Primary
    Rhyolite
    Silica Content
    High (>68% 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 Activity676 years agoHistoricalHistorically active

    Monitoring & Alert Status

    Monitoring Networks

    Global Volcanism Program
    International eruption database

    Current Status

    Normal
    No recent activity. Routine monitoring continues.

    Nearby Volcanoes in Southwestern Pacific Volcanic Regions

    Regional Volcanic Activity
    The Southwestern 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: 253060
    • Evidence: Eruption Dated
    • Epoch: Holocene

    About the Photo

    The Dawson Straits, seen in this NASA Landsat image, is located between eastern Fergusson Island (upper left) and northwestern Normanby Island (lower left) in the D'Entrecasteaux island group. The area contains a volcanic field with several young volcanic centers that erupted rhyolitic obsidian flows. Mount Oiau is located on the narrow peninsula (left center) forming the southernmost point on Fergusson Island. A large crater is visible on Dobu Island, southeast of Oiau. Young volcanic rocks are also found on Sanaroa Island (upper right).

    NASA Landsat 7 image (worldwind.arc.nasa.gov)

    Basic Information

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