Gemini Seamount,
New Hebrides Island Arc,
Vanuatu Islands

Update 002

Date:         Wed, 21 Feb 1996 10:05:44 MST
From: Jean-Philippe EISSEN - ORSTOM Brest
Subject:      SW Pacific submarine eruption
A submarine eruption was observed in the southern New Hebrides island arc (Vanuatu - SW Pacific).

The activity was first observed by a ship cruising in this area on february 18th around 18H00 (in local time = GMT +10). It was described as: "continual steam and frequent vertical bursts of very dark water" The position given by the ship is : 20 58.8'South and 170 17.1'East A flight of a New Caledonia coastguards Guardian plane february the 19th described the activity as : "a white spot in the middle of a black patch with steaming of possibly floating pumices".

It corresponds to the Eastern Gemini seamount, one of the two Gemini seamounts which represent the southern submarine extension of the New Hebrides island arc. It is located about a 100 km south of Anatom island and culminates at about 80 m below sea level. Several basalts samples and one andesite were dredged on this seamount in 1989 (Monzier et al., 1993. Volcanol. Geothermal. Res., 57:193-217). There were described as glassy, vesicular and extremely fresh in the "Gemini cruise report" (Bargibant et al. 1989, ORSTOM Noumea Earth Sciences Report nber 12, 13 pages, unpublished). As all the samples were devoid of marine animal traces, the activity was described as very recent. The Western Gemini seamount is located near 21 00' South and 170 03' East and culminates at 30 meters below sea level. Its activity seems to be older as the marine life is well developed around its summit observed by divers and dredged.

Informations Contact :
Bernard Pelletier, Centre ORSTOM de Noumea, BP A5, Noumea, New Caledonia
fax (+687) 26 43 26, e-mail :
Michel Lardy, ORSTOM, BP 76, Port Vila, Vanuatu
fax (+678) 23 276, e-mail :
Michel Monzier, Claude Robin, ORSTOM, A.P. 17-11-6596 CCI, Quito, Ecuador
fax (+593) 24 48 699, e-mail :
Jean-Philippe Eissen, Centre ORSTOM de Brest, BP 70, 29280 Plouzane, France
fax (+33) 98 22 45 14, e-mail :

Jean-Philippe EISSEN    (ORSTOM - UR 14 & GDR GEDO)
Centre ORSTOM de Brest, B.P. 70, 29280 Plouzane cedex, France
tel (33) 98 22 46 65    fax (33) 98 22 45 14
E-mail : (ou/or