Elevation 140 m (460 ft) Location Papua New Guinea Last eruption May 2007 | Prominence 140 m (460 ft) Mountain type Stratovolcano Island group Bismarck Archipelago | |
Similar Blup Blup, Long Island, Ambitle, Tanga Islands, Umboi Island | ||
Ritter Island is a small crescent-shaped volcanic island 100 kilometres north-east of New Guinea, situated between Umboi Island and Sakar Island.
Map of Ritter Island, Papua New Guinea
There are several recorded eruptions of this basaltic-andesitic stratovolcano prior to a spectacular lateral collapse which took place in 1888. Before that event, it was a circular conical island about 780 metres high. At about 5:30 am local time on 13 March 1888 a large portion of the island, containing perhaps 5 km3 of material slid into the sea during a relatively minor, possibly VEI 2, phreatic eruption. Eyewitnesses at Finschhafen, 100 km to the South, heard explosions and observed an almost imperceptible ash fall. Tsunamis 12–15 metres high were generated by the collapse and devastated nearby islands and the adjacent New Guinea coast killing around 3000 people.
The collapse left a 140 metre high 1900 metre long crescent-shaped island with a steep west-facing enscarpment. 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.