Ritter Island

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  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 5.52°S
  • 148.121°E

  • 140 m
    459 ft

  • 251070
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

23 May-29 May 2007

On 30 May, RVO reported observations of Ritter Island following reports of a possible eruption and "sea surges" that destroyed homes on 19 May. On the S part of the island, scorched vegetation was observed and dead marine life (mainly reef fish) was seen around the coast line at heights of 4-6 m a.s.l. There was no evidence of fresh volcanic material, but a new landslide scar extended from the upper most part of the island down to sea level. Several more landslide scars were seen on the W wall. The estimated wave surge height resulting from the 19 May event reached 4-10 m, particularly around the S part of the island. Rockfalls continued to produce plumes that could be seen from a distance.

Source: Rabaul Volcano Observatory (RVO)



 Available Weekly Reports


2007: May
2006: November
2002: July


23 May-29 May 2007

On 30 May, RVO reported observations of Ritter Island following reports of a possible eruption and "sea surges" that destroyed homes on 19 May. On the S part of the island, scorched vegetation was observed and dead marine life (mainly reef fish) was seen around the coast line at heights of 4-6 m a.s.l. There was no evidence of fresh volcanic material, but a new landslide scar extended from the upper most part of the island down to sea level. Several more landslide scars were seen on the W wall. The estimated wave surge height resulting from the 19 May event reached 4-10 m, particularly around the S part of the island. Rockfalls continued to produce plumes that could be seen from a distance.

Source: Rabaul Volcano Observatory (RVO)


16 May-22 May 2007

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.

Source: Australian Associated Press


1 November-7 November 2006

On 17 October, a villager from Kampalap (on the E coast of Siassi Island) reported unusual activity from Ritter Island to the RVO. The activity consisted of small felt earthquakes followed by emissions of white vapor and diffuse ash clouds. Rocks slid down the inner crater wall. Ashfall, which the observer indicated was not from Langila, was reported in Kampalap.

Source: Rabaul Volcano Observatory (RVO)


31 July-6 August 2002

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.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


Summary of eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2007 May 19 2007 May 21 (?) Confirmed 1 Historical Observations
2006 Oct 17 2006 Oct 17 (?) Confirmed 1 Historical Observations
[ 2002 Aug 2 ] [ 2002 Aug 2 ] Uncertain 2  
1974 Oct 17 1974 Oct 17 Confirmed 1 Historical Observations 600-900 m W of Ritter Island
1972 Oct 9 1972 Oct 9 Confirmed 1 Historical Observations West of Ritter Island
1888 Mar 13 1888 Mar 13 Confirmed 2 Historical Observations
1887 Feb 2 1887 Feb 5 Confirmed 2 Unknown
[ 1885 Jan 13 (?) ] [ Unknown ] Uncertain    
[ 1878 Dec 31 ± 30 days ] [ Unknown ] Uncertain    
[ 1848 Apr 13 ] [ 1848 Jul 10 (?) ] Uncertain    
1793 Jun 29 Unknown Confirmed 2 Historical Observations
1700 Mar 24 Unknown Confirmed 3 Historical Observations

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

Cooke R J S, 1981a. Eruptive history of the volcano at Ritter Island. Geol Surv Papua New Guinea Mem, 10: 115-124.

Fisher N H, 1957. Melanesia. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 5: 1-105.

Johnson R W, 1987. Large-scale volcanic cone collapse: the 1888 slope failure of Ritter volcano, and other examples from Papua New Guinea. Bull Volc, 49: 669-679.

Johnson R W, Taylor G A M, Davies R A, 1972. Geology and petrology of Quaternary volcanic islands off the north coast of New Guinea. Aust Bur Min Resour Geol Geophys Rec, 1972/21: 1-127.

Lowenstein P L, 1982. Problems of volcanic hazards in Papua New Guinea. Geol Surv Papua New Guinea Rpt, 82/7: 1-62.

Silver E, Day S, Ward S, Hoffmann G, Llanes P, Driscoll N, Appelgate B, Saunders S, 2009. Volcano collapse and tsunami generation in the Bismarck Volcanic Arc, Papua New Guinea. J Volc Geotherm Res, 186: 210-222.

Prior to 1888, Ritter Island was a steep-sided, nearly circular island about 780 m high. The current small, 140-m-high island is a topographically insignificant, 1900-m-long arcuate feature 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 remnant with a steep west-facing scarp that descends below sea level. 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.