Mt Giluwe is the highest volcano in Pacific Oceania and considered one of "the 7 volcanic summits" (not Mauna Kea on Hawaii, as many think: Giluwe is 162 m higher). It is an ancient extinct shield volcano with 2 prominent 400 m high cones forming its summit, called the main peak and the slightly lower eastern peak (4300 m). Occasionally, the summit receives snow fall.

Mt Giluwe's flanks are covered by many lava flows, which reach up to 30 m thickness. The flanks are cut by radial erosion valley which provide excellent outcrops of volcanic strata. There are many flank cinder cones with up to 30 meter deep craters and up to 200 m diameter. Most of the flank craters are breached to the downward side.

The large shield of Mt Giluwe has a basal diameter of 30 km. It receives an annual rainfall of 2500 mm and frost can occur above 4000 m.

Most of the mountain is covered with montane rain forest and grassland.



Subglacial eruptions of Mt Giluwe volcano:

During the Pleistocene, Mt Giluwe was covered by an ice cap which extended as low as the 3200 to 3500 m level. The volcano erupted under the ice during its last period of activity. Subglacial eruptions from volcanoes in the tropics are elsewhere only known from Kilimanjaro and Mauna Kea.

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Sources:

- D.H Blake and E Löffler (1971) "Volcanic and Glacial Landforms on Mount Giluwe, Territory of Papua and New Guinea", GSA Bulletin; v. 82; no. 6; p. 1605-1614