Ritter Island is a small crescent-shaped volcanic island north-east of

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torres ...

, situated between

Umboi Island Umboi (also named Rooke or Siassi) is a volcanic island between the mainland of Papua New Guinea and the island of New Britain. It is separated from New Britain by the Dampier Strait and Huon Peninsula, and New Guinea by the Vitiaz Strait. It h ...

and

Sakar Island Sakar Island is a volcanic island north-west of New Britain in the Bismarck Sea, at . It is a stratovolcano with a summit crater lake. No recorded eruptions are known. See also * List of volcanoes in Papua New Guinea This is a list of active ...

. There are several recorded eruptions of this

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

ic-

andesitic Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomin ...

stratovolcano A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and peri ...

prior to a spectacular lateral collapse which took place in 1888. Before that event, it was a circular conical island about high.

1888 eruption

At about 5:30 am local time on 13 March 1888 a large portion of the island, containing perhaps of material slid into the sea during a relatively minor, possibly VEI 2, phreatic eruption. Eyewitnesses at

Finschhafen Finschhafen is a town east of Lae on the Huon Peninsula in Morobe Province of Papua New Guinea. The town is commonly misspelt as Finschafen or Finschaven. During World War II, the town was also referred to as Fitch Haven in the logs of some U.S ...

, to the south, heard explosions and observed an almost imperceptible ash fall.

Tsunami A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater exp ...

s high were generated by the collapse and devastated nearby islands and the adjacent New Guinea coast killing around 3,000 people.Ritter Island at Volcano World
/ref> The collapse left a high, long crescent-shaped island with a steep west-facing escarpment. At least two small eruptions have occurred offshore since 1888, one in 1972 and another in 1974, which have resulted in the construction of a small submarine edifice within the collapse scar.

References

Islands of Papua New Guinea Subduction volcanoes Active volcanoes Stratovolcanoes of Papua New Guinea Holocene stratovolcanoes {{PapuaNewGuinea-geo-stub