Report on Ritter Island (Papua New Guinea) — 31 July-6 August 2002
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 31 July-6 August 2002
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2002. Report on Ritter Island (Papua New Guinea). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 31 July-6 August 2002. 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)
Qantas Airlines reported to the Darwin VAAC that an ash cloud to about ~3 km a.s.l. was observed on 2 August at 1450. Analysis of satellite data did not show ash.
Geologic Background. 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.