Sonar image shows the submarine Kick-’em-Jenny cone from the NE in 1996
If you ask a volcanologist what their favourite volcano name is, Kick ’em Jenny is often a contender. This brilliantly named volcano is a submarine volcano about 8 km north of Grenada in the Caribbean Sea. It is also one of the most frequently active volcanoes in the eastern Caribbean and is monitored by the University of the West Indies Seismic Research Centre (UWI).
Vertically exaggerated SeaBeam image shows Kick ’em Jenny and newly identified craters and domes discovered in March 2003. Kick ’em Jenny’s summit occurs adjacent to the crater rim at a depth of ~ 185 m. The deepest point on Kick ’em Jenny’s crater floor lies at ~264 m depth. The image’s left side is drawn N-S (i.e. N towards the upper left). Tick marks along the margins are at 0.01 degree intervals, a spacing equivalent to 1.8-1.9 km. The distance between Kick ’em Jenny and Kick ’em Jack is about 4 km. Image courtesy of NOAA and Seismic Research Institute
Janine Krippner
Kick ’em Jenny first made the world aware of its presence in 1939, when earthquakes were felt in Grenada and produced higher waves along the coastlines. It eventually reached sea level, producing an explosive eruption with ash and steam plumes. The life cycle of this volcano involves growing towards the surface, then being worn back down. Currently, the summit is around 200 metre below the surface of the sea. It is a beautiful example of the early stages of how other eastern Caribbean islands formed.
The volcano is a site of geothermal activity, where fluids and gases are vented at temperatures that can reach around 150°C. In 1989, a submersible was sent down to check it out, and an updraft over the crater pushed the craft towards the surface. That would have been an experience for the pilot onboard!
There is a 1.5 km exclusion zone around the 300 metre wide crater in place for marine vessels. It is located within a main shipping route, as well as a popular area for recreational sea-goers. It doesn’t take too much imagination to grasp why you don’t want to be on a boat directly above an active volcano.
Eruptions can occur with little to no perceptible warning. A fascinating and rather scary process can occur when a large amount of gas is released into the water above. It reduces the density of the water, and water density is important for the buoyancy of marine vessels. If a boat enters the wrong area at the wrong time, it can lose that critical buoyancy and sink.
Lyn Topinka -Creative Commons, wikimedia
This likely occurred in August 1944, when the Island Queen disappeared with more than 60 souls onboard. No debris was found. This would have been a spooky and devastating event, and we can see how myths like the Bermuda Triangle take hold.
One misconception that has spread because of understandable fear is the threat of large tsunamis. While volcano-induced tsunamis are definitely a major concern, the hazard at Kick ’em Jenny has been studied, and the conclusion is that it is not a large threat at this time. Not all eruptions produce tsunamis, and the tsunamis it does produce can be quite small.
This is another example of how we must study each individual volcano to understand the dangers to communities. It’s also important to keep studying the volcano, as the situation may change as activity progresses.
If you want to learn more, all this information is from the UWI website. You can also learn about the other volcanoes of the eastern Caribbean, including explosive eruptions that have had devastating impacts on the islands.
Sonar image shows the submarine Kick-’em-Jenny cone from the NE in 1996. Depths are nominally meters but have an uncertainty of about 10%. This image shows the upper several hundred meters of the en:submarine volcano:submarine volcano that lies 8 km off the north shore of Grenada and rises 1300 m from the sea floor of the Caribbean Sea. Photo: Creative Commons, Wikimedia
