Experts in a lava over big Jenny

An ominous volcano deep in the Caribbean is making threats from volcanoes in New Zealand and Italy this month pale into insignificance, a Southampton geologist said this week.

Kick 'em Jenny, a submarine volcano just north of Grenada, has erupted ten times over the past 20 years and vulcanologists fear there could be a much bigger eruption, says Bramley Murton, of the Southampton Oceanography Centre. Yet the volcano has been forgotten because it is under the sea, he added.

Dr Murton is hoping to visit the Caribbean to carry out tests on Kick 'em Jenny, with scientists from the University of the West Indies. They know the volcano has grown in height by 50 metres over the past ten years, but they do not know crucial details about it.

"We believe it poses a threat not dissimilar to that of Krakatoa," said Dr Bramley.

He has calculated that it could, at its worst, cause tidal waves of 50 metres on Grenada and 20 metres on the north shore of Venezuela. Within a few hours the effect would be felt as far away as Alaska.

Dr Bramley said submarine volcanoes are more threatening than land-based ones for several reasons. Once they erupt, sea water gushes into the molten rocks, heats up to over 1,000 degrees C and turns to steam, causing an explosion.

A submarine eruption yields a wave that stretches down to the ocean floor. As such a deep wave approaches the land it is compressed as the water becomes shallower.

In addition, Kick 'em Jenny has a particularly explosive combination of water and high-silicate lava.

Dr Murton hopes to map the volcano with an echo-sounder, search for the equivalent of smoke to detect where the activity is, and leave instruments on its sides for a year to detect changes.