Monowai Seamount | John Seach


Kermadec Islands, New Zealand

25.88 S, 177.18 E
summit elevation -135 m
submarine volcano

Monowai seamount is located halfway between Tonga and the Kermadec Islands. The submarine volcano is one of the most active in the Kermadec arc. Acoustic T-wave earthquake swarms are recorded every few years at the volcano.

2012 Eruption
Eruptions began at Monowai volcano on 3rd August 2012. This eruption was not responsible for the large pumice raft which was detected 85 nautical miles SW of Raoul Island on 1st August 2012.

2009 Activity
Activity was recorded at Monowai volcano in early and mid-May, early July, mid-September, late October, mid-November, late November to early December and mid-December. On 28th October discoloured water was observed at the volcano during a flyover.

2007 Earthquake
A major earthquake (mag 7.8) hit 33 km west of the seamount on 9th December 2007 at 07:28 pm. The earthquake focus was 149 km depth. No tsunami was generated.

2002 Activity
A long duration (6-8 minute) swarm was recorded on 24 May 2002. Volcanic eruptions have created landslides which increased the summit depth from -65 m in 1998 to the present depth of -135 m.

Further Reading
Watts, A.B et al. 2012. Rapid rates of growth and collapse of Monowai submarine volcano in the Kermadec Arc. Nature Geoscience, 5(7), pp.510-515.

Wright, I.C. et al. 2008. Collapse and reconstruction of Monowai submarine volcano, Kermadec arc, 19982004. Journal of Geophysical Research: Solid Earth, 113(B8).

Davey, F.J., 1980. The Monowai seamount: An active submarine volcanic centre on the Tonga-Kermadec ridge (Note). New Zealand journal of geology and geophysics, 23(4), pp.533-536.

Monowai Seamount Eruptions

2012, 2009, 2005, 2003, 2002, 1997-98, 1997, 1996, 1995, 1990-91, 1988, 1986, 1982, 1980, 1977, 1977-79, 1944?