Five-meters digital terrain model of the crater of the volcano derived from multibeam echo sounder data collected during the November 1-18, 2013 NA039 E/V Nautilus cruise. OET: Ocean Exploration Trust; SRC: Seismic Research Centre, The University of the West Indies.
Five-meters digital terrain model of the crater of the volcano derived from multibeam echo sounder data collected during the November 1-18, 2013 NA039 E/V Nautilus cruise. OET: Ocean Exploration Trust; SRC: Seismic Research Centre, The University of the West Indies.

Grenada’s Underwater Volcano Kick ‘em Jenny Stirs

Mother Nature was on Caribbean mariners’ minds in July. Not only did the Atlantic’s hurricane season start on the first day of the month, but undersea volcano Kick ‘em Jenny erupted.

“On July 23rd and 24th we recorded two strong seismic signals from the volcano that we interpreted as evidence of a submarine explosion or eruption,” tells Dr. Frederic Dondin, research fellow in volcanology at the University of the West Indies’ Seismic Research Center (UWISRC) in Trinidad & Tobago. “Signals of the explosions were picked up at our station, by seismic stations to the north in the French West Indies of Martinique and Guadeloupe and also as far north as Puerto Rico.”

July marked the first eruption for Kick ‘Em Jenny, located five miles north of Grenada (12.18°N, 61.38°W), since 2001. The short 14-year gap isn’t surprising. According to scientists, Kick ‘em Jenny is the only ‘live’ submarine volcano in the Eastern Caribbean. It’s also the most frequent volcano, under or above the sea, to erupt in the region, having done so over a dozen times since it was first discovered in 1939.

Kick ‘em Jenny could present a couple of big problems to mariners if she were to erupt more forcefully. First, hot rocks thrown up in the air via a column of water could endanger passing boats up to three miles away. Secondly, large sea waves or tsunamis could result. The worst case scenario, because the volcano’s vent is so far undersea at 880-feet, is a 30-foot high wave in open waters. Thirdly, large amounts of gas bubbles released into the water even during quite times can lower the density of seawater above the volcano’s vent so much that ships can lose buoyancy and sink.

“In the case of Kick ‘em Jenny there is always a restricted area for marine traffic. This is a distance of one mile during a non-volcanic activity period. In a time of unrest, as with the confirmed eruptive activity we saw in July, the restricted area is increased to three miles,” says Dondin.

The first moment Kick ‘em Jenny displays signs of unrest, as it did in July, UWISRC scientists reports directly and daily to officials at Grenada’s National Disaster Management Agency. From there, the Agency issues marine security warnings and public alerts to mariners in the area. This system assures it won’t take long for mariners to receive a warning the next time Kick ‘em Jenny erupts.

For more information, visit: www.uwiseismic.com

 

Carol M. Bareuther, RD, is a St. Thomas, U.S. Virgin Islands based marine writer and registered dietitian.

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