Sunday, Jan 10, 2010
2 large earthquakes magnitude 7.2 and 6.5 occurred 88 km NW of Kavachi volcano at 9:36 and 9:48 am local time on 4 January 2010. ... [more]
Kavachi volcano eruptions
submarine volcano -20 m / -66 ft
Solomon Islands, -9.02°S / 157.95°E
Eruption list: 2007, 2004, 1999-2003, 1999 (Feb-May), 1998 (?), 1997, 1991, 1986, 1985, 1982, 1981 (Sep) (?), 1980-81, 1978, 1977 (Jul), 1977 (Feb), 1976, 1975, 1974, 1972, 1969-70, 1966, 1965, 1963-64, 1962, 1961, 1958, 1957, 1952-53, 1951, 1950, 1942, 1939
On 2 April 2007, the Solomon Islands were struck by a major (8.1 magnitude) earthquake followed by a large tsunami.
The eruption possibly triggered the small eruption of Kavachi volcano observed at the same time.
After 8 months of slumber, an eruption on 15 March 2004 breached the water surface above Kavachi volcano, producing spectacular roster-tail ash jets caused by explosive magma-water interaction.
In January 2002 the summit of Kavachi's summit was at 60 m depth. At the surface, brown muddy bubbly upwelling water as well as sulfur were observed at the surface. A large stain of discolored water extended many kilometers from the vent. My 16 March 2002 the summit had grown to a depth of -34 m. Occasional surtseyan explosions were seen from Gatokae Island.
In October and November 2002 Kavachi formed a new island that reached 10-15 m above sea level. The island was still visible in August 2003, but had disappeared in September, when the summit of the volcano was measured at 32 m below sea level.
On 29 January the sea water near the volcano was discolored and dirty, but no eruptions.
The location of the new island was about 3 km NE of Kavachi's summit, placed at 9.00°S, 157.97°E.
On 5 June, a vigorously active lava fountain reaching about 25 m high and producing an ash plume more than 2,500 m height were observed. After a phase of powerful explosions, the eruption ended in late June and the island disappeared quickly.
A second eruption occurred in July 1986, when explosions up to 60-90 m height were observed, with incandescent lava blocks in the inner parts of the ejections. The July eruption only lasted 2 days.
The eruption continued until after 25 February 1981 and ended sometime before mid September 1981.
On 14 July 1978, the island N-S elongate island and had a central cone about 30 m high. Strombolian activity occurred from the central vent, ejecting scoria to up to 400 m height. A lava flow was observed running down the S flank. A small secondary vent formed near sea level on the E coast.
By 16 July 1978, when the island could be observed again, the S half of the island, including the central vent, had dropped along an E-W fault. There was a steep scarp that formed the new S edge of the island at its place. Eruptive activity continued with infrequent explosions from the secondary vent on the E coast.
When next observed on 28 July, the eruption had ended. A small rocky island, about 15 m long, 5 m wide and no more than 3 m high remained at the eruption site. The island was expected to be destroyed by wave action within a few days to a few weeks.
Source: Smithsonian / GVP monthly activity updates
The eruption quickly increased and explosions reached about 60 m on 4 September, when a change of the eruption column from white steam and spray to "smoke" (=ash) was noted. Eruption height on 7 Sep was 90 m, and a cone surfaced 1.5-3 m above sea level later that day and was seen erupting lava. The next day, the cone had grown to 9 m above sea level and measured 40 m across. Liquid lava was seen from its vent and a lava flow poured to the NW. Strombolian activity threw incandescent bombs to 150 m height.
The eruption was weaker on 9 September and the island showed signs of breaking up by wave erosion. The lava flow ended between 9-11 Sep, but explosions continued at intervals between 30 s - 2 minutes.
On 13 October, explosions continued, but the island had disappeared. At the site, the sea was discolored over an area of 100 m. Ejections reached about 30 m height.
The eruption ended probably in late October.