Epi Island, located to the west of the main volcanic arc of the New Hebrides, consists mainly of two quaternary volcanoes, Mount Allombei to the west and Mount Pomare (Tavani Kutali) to the east .
The Tavani Ruru, which forms an elongated extension to the east of Epi Island through a narrow isthmus, is linked to the caldera of the Kuwae volcano in the east.
The Pomare volcano is the highest point of the island and has three well-preserved adjacent cones with craters of young peaks.
The volcano Pomare is truncated on its east side by the caldera of East Epi, largely underwater, which was the source of all the historical eruptions.
Off the eastern coast of Epi Island, there is a large caldera, with submarine post-caldera cones active in historical times.
Three small underwater basaltic and dacitic cones, known as Epi A, Epi B and Epi C, are located along the northern edge of the open caldera.
Ephemeral islands were formed during eruptions in 1920 and 1953, and the shallowest cone top, Epi B, was 34 m below sea level at the time of the 2001 study.
(Smithsonian Institution - John Seach)
Bathymetry in the eastern area of Epi. Epi A, B, C. Submarine mounts Epica A, B, C. Map carried out during the VATATERM sea campaign with the Simrad EM1002 of the IRIS NO Alis (14 March 2004) (Ballu, Calmant et al, 2004 ). Isobaths: 20 m
Explosion of the submarine volcano EPI B, February 19 2004 © Azur
Discoloration of Epi B area , 1958. © Roland Priam
Epi B Volcano:
This submarine volcano, located east of the island of Epi, has a periodic activity which results in the coloration of sea water from surfaces in yellow and explosions.
A violent activity is reported between the Lopévi and Epi islands in 1920 (William and Warden, 1964). In February 1953 a major eruption accompanied by the projection of volcanic products (a hundred meters high) is reported; It causes rafts of pumice on about 1000 km² and the emergence of a cone which is quickly destroyed (Warden, 1967).
A coloring of the waters was noted in 1958. A further major eruption was reported in July 1960.
Only water colorings appear to have been observed in 1971, 1972, 1973, 1974, 1979, 1988, 1997 and 2001.
Pumps of pumice were observed in March 2002 and 2004, explosions and surface manifestations.
Marine surveys of hydrography and geology-geophysics confirmed the Epi B volcano, in addition to its activity, maintaining a summit zone located at 34 meters depth.
The volcano Epi B is a cone 300 meters high for a diameter at the base of 1800 m with a peak at 35-40 m depth (- 34 m for the highest edge to the northwest of the building ) And a crater about 150 m in diameter and located at - 90m below sea level.
This crater is open to the north along a break of 60 m wide. The observations of the last century and the recent events confirm the permanent activity of Epi B, which constitutes a threat to the local populations located about 5 km.