Kavachi Volcano | John Seach


Rejo te Kvachi

Western Province, Solomon Islands

9.02 S, 157.95 E,
summit elevation -20 m,
submarine volcano

Kavachi is a shallow submarine volcano which has formed islands on 9 occasions. Kavachi volcano is located at a tectonic location called a triple junction. It is located on the Pacific plate only 30 km northeast of its convergent boundary with the downgoing Indo-Australian plate.

Island formation is temporary and a lack of stabilising lava flows means that wave action washes it away after a few months. Islands occur at different locations, indicating multiple active vents.

2014 Eruption
A NASA satellite image on 29th January 2014 showed water discolouration at Kavachi undersea volcano, Solomon Islands. This indicated possible renewed eruptive activity.

2010 Earthquakes
A magnitude 7.2 earthquake hit 88 km NW of Kavachi volcano at 9:36 am on 4th January 2010. A tsunami possibly hit uninhabited Tetepare Island. Landslides occurred on Tetepare and Rendova islands. A large aftershock (magnitude 6.3) hit 40 km SW of Kavachi volcano on 9th January 2010.

2008 Earthquake
A large earthquake (Mag 6.1) hit Kavachi volcano in the Solomon Islands, on 9th September 2008 at 11:22 pm local time. The earthquake had a focus at a depth of 10 km. 

2007 Earthquake and Eruption
An eruption of Kavachi volcano was triggered by a magnitude 8.1 earthquake on 2nd April 2007. Observations from Biche Village on the South coast of Gatokae Island reported an eruption column. On 6th April 2007 there was upwelling over the vent and water discolouration.

2004 Eruption
Eruptions of Kavachi volcano occurred on 15th March 2004. The eruption end date is unknown.

2002 Eruptions
In January 2002 Kavachi's summit was measured at a depth of 60 m. Yellow-brown upwelling was observed, and a yellow sulphur on the ocean surface. Bubbles rose to the surface and a discoloured water was visible several kilometres from the volcano. Occasional eruptions were visible from Gatokae Island (Nggatokae) ~35 km NE of Kavachi. During 2002 measurements were made of shifting summit depths. On 16th March 2002 summit depth was 34 m. In October and November 2002 eruptions of Kavachi formed an island 10-15 m above sea level. By 16th November 2003 the volcano summit had eroded to 32 m below sea level.

2001 Eruptions
During August to mid September 2001 Kavachi volcano erupted daily. Ash emissions reached a height of 400 m above sea level.

2000 Eruptions
Eruptions of Kavachi volcano were observed by a scientific team on board an Australian research ship R/V Franklin on 14th May 2000. The volcano summit was 2-5 m below sea level. Surtseyan "rooster-tail" eruptions were observed with incandescent blocks of lava ejected 70 m high and ash reaching 500 m altitude. The eruptions were described as being similar to Myojin-sho in 1952–1953, although on a smaller scale.

1997 Eruption
A pilot reported eruptions of Kavachi volcano on 16-17 January 1887. Ash emissions reached an altitude of 2100 m.

1991 Eruptions
Eruptions of Kavachi volcano in 1991 formed a new island which was observed on 4th May during a helicopter overflight. The island was 300x150 m wide, 30 m high, and contained a lava pond 50 m in diameter. The location of the island was initially uncertain, but later placed at 9.00°S, 157.97°E, 3 km NE of Kavachi's summit.

1985-86 Eruptions
Eruptions of Kavachi volcano began on 9th December 1985. On 31st December observations from a plane showed ejection of rock, mud and steam to a height of 30 m. Eruptions ended by 3rd March 1986. Eruptions resumed in July 1986 with material ejected 90 m high.

1980-81 Eruptions
Small submarine eruptions began at Kavachi volcano in October 1980 and periodic observations were made of activity until 25th February 1981. An overflight in mid September 1981 showed no eruptions.

Further reading
Baker, E.T., Massoth, G.J., de Ronde, C.E., Lupton, J.E. and McInnes, B.I., 2002. Observations and sampling of an ongoing subsurface eruption of Kavachi volcano, Solomon Islands, May 2000. Geology30(11), pp.975-978.

Kavachi Volcano Eruptions

2014, 2007, 2004, 2003, 2001, 2000, 1997, 1991, 1985-86, 1982, 1980-81, 1978, 1977, 1977, 1976, 1975, 1974, 1972, 1969-70, 1966, 1965, 1963-64, 1962, 1961, 1958, 1957, 1952-53, 1951, 1950, 1942?, 1939.