Monowai Seamount

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  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 25.887°S
  • 177.188°W

  • -132 m
    -433 ft

  • 242050
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

8 August-14 August 2012

According to Institute of Geological & Nuclear Sciences Limited (GNS) in a media release on 11 August, the Laboratoire de Géophysique (Papeete, Tahiti) reported that seismographs in Rarotonga recorded eruptive activity at Monowai seamount on 3 August. The activity then stopped overnight.

Source: New Zealand GeoNet Project



 Available Weekly Reports


2012: August


8 August-14 August 2012

According to Institute of Geological & Nuclear Sciences Limited (GNS) in a media release on 11 August, the Laboratoire de Géophysique (Papeete, Tahiti) reported that seismographs in Rarotonga recorded eruptive activity at Monowai seamount on 3 August. The activity then stopped overnight.

Source: New Zealand GeoNet Project


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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2012 Aug 3 2012 Aug 4 Confirmed 0 Hydrophonic
2008 Feb 8 (?) Unknown Confirmed 0 Hydrophonic
2006 Dec 12 2006 Dec 31 (?) Confirmed 0 Hydrophonic
2005 Mar 2 2006 Jun 27 Confirmed 0 Hydrophonic
2003 Apr 10 2004 Sep Confirmed 0 Hydrophonic
2002 Nov 1 2002 Nov 24 Confirmed 0 Hydrophonic
2002 May 24 2002 May 24 Confirmed 0 Hydrophonic
1999 Jun 6 1999 Jun 11 Confirmed 0 Hydrophonic
1997 Dec 15 1998 Feb 4 (?) Confirmed 0 Hydrophonic
1997 Apr 18 1997 Apr 21 Confirmed 0 Hydrophonic
1996 Sep 20 1996 Sep 22 Confirmed 0 Hydrophonic
1995 Nov 27 1995 Nov 30 Confirmed 0 Hydrophonic
1990 May 30 1991 Mar 25 Confirmed 0 Hydrophonic
1988 Sep 8 1988 Sep 8 Confirmed 0 Hydrophonic
1986 Jun 1986 Jun Confirmed 0 Hydrophonic
1982 May 1982 May Confirmed 0 Hydrophonic
1980 Jan 1980 Jan Confirmed 0 Hydrophonic
1979 Feb (?) 1979 Apr 19 (?) Confirmed 1 Hydrophonic
1978 Feb 1978 Jul Confirmed 0 Hydrophonic
1977 Oct 17 1977 Oct 27 (?) Confirmed 0 Historical Observations
1977 Apr 1977 Apr Confirmed 0 Hydrophonic
[ 1944 ] [ Unknown ] Uncertain 0  

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.

Brothers R N, Heming R F, Hawke M M, Davey F J, 1980. Tholeiitic basalt from the Monowai seamount, Tonga-Kermadec ridge (Note). New Zeal J Geol Geophys, 23: 537-539.

Davey F J, 1980. The Monowai Seamount: an active submarine volcanic centre on the Tonga-Kermadec Ridge (note). New Zeal J Geol Geophys, 23: 533-536.

Latter J H, 1978. Submarine eruption south of Tonga. New Zeal Volc Rec, 7: 61.

Latter J H, Lloyd E F, Smith I E M, Nathan S, 1992. Volcanic hazards in the Kermadec Islands, and at submarine volcanoes between southern Tonga and New Zealand. New Zeal Ministry Civil Defense, Volc Hazards Inf Ser, 4: 1-45.

Smithsonian Institution-SEAN, 1975-89. [Monthly event reports]. Bull Scientific Event Alert Network (SEAN), v 1-14.

Wright I C, Chadwick W W Jr, de Ronde C E J, Reymond D, Hyvernaud O, Gennerich H-H, Stoffers, P, Mackay K, Dunkin M A, Bannister S C, 2008. Collapse and reconstruction of Monowai submarine volcano, Kermadec arc, 1990-2004. J Geophys Res, doi:10.1029/2007JB005138 .

Monowai seamount, also known as Orion seamount, rises to within 100 m of the sea surface about halfway between the Kermadec and Tonga island groups. The volcano lies at the southern end of the Tonga Ridge and is slightly offset from the Kermadec volcanoes. Small parasitic cones occur on the north and west flanks of the basaltic submarine volcano, which rises from a depth of about 1500 m and was named for one of the New Zealand Navy bathymetric survey ships that documented its morphology. A large 8.5 x 11 km wide submarine caldera with a depth of more than 1500 m lies to the NNE. Numerous eruptions from Monowai have been detected from submarine acoustic signals since it was first recognized as a volcano in 1977. A shoal that had been reported in 1944 may have been a pumice raft or water disturbance due to degassing. Surface observations have included water discoloration, vigorous gas bubbling, and areas of upwelling water, sometimes accompanied by rumbling noises.