Ritter Island
Ritter Island is a small crescent-shaped volcanic island 100 kilometres (62 mi) north-east of New Guinea, situated between Umboi Island and Sakar Island.
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 (2,560 ft) high.