Report on Ritter Island (Papua New Guinea) — 16 May-22 May 2007
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
16 May-22 May 2007
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2007. Report on Ritter Island (Papua New Guinea). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 16 May-22 May 2007. Smithsonian Institution and US Geological Survey.
Papua New Guinea
5.519°S, 148.115°E; summit elev. 75 m
All times are local (unless otherwise noted)
According to a news article, "sea surges" destroyed four homes and a boat following an eruption of Ritter Island on 19 May. About 1,500-2,000 people on Siassi Island moved to higher ground. Villagers reported seeing plumes from the island, hearing rumbling noises, and feeling earthquakes. The article also mentioned that RVO and the Geophysical Observatory in Port Moresby did not record any seismic activity from the eruption.
Geological Summary. Prior to 1888, Ritter Island was a steep-sided, nearly circular island about 780 m high between Umboi and Sakar Islands. Several historical explosive eruptions had been recorded prior to 1888, when large-scale slope failure destroyed the summit of the conical basaltic-andesitic volcano, leaving the arcuate 140-m-high island with a steep west-facing scarp. Devastating tsunamis were produced by the collapse and swept the coast of Papua New Guinea and offshore islands. Two minor post-collapse explosive eruptions, during 1972 and 1974, occurred offshore within the largely submarine 3.5 x 4.5 km breached depression formed by the collapse.
Source: Australian Associated Press