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Dawson Strait Group

Volcanic field · Papua New Guinea · 500m

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).
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). · Photo: NASA Landsat 7 image (worldwind.arc.nasa.gov)
Type
Volcanic field
Country
Papua New Guinea
Region
Southwestern Pacific Volcanic Regions / Trobriand Volcanic Province
Elevation
500m
Coordinates
-9.620, 150.880
Last eruption
1350
Tectonic setting
Subduction zone / Continental crust (> 25 km)
Landform
Cluster
Major rock type
Rhyolite
Geological summary

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.

Eruption history

Summary (VEI over time)
Click a bar to see individual eruptions
1350~1350 · 1 eruptions · max VEI ?13501350135113511351

Detailed timeline

  1. 1350VEI ?Geological estimate
    1350 – Ongoing
    Oiau

External links

⚠ For reference only. Not for emergency response.