PORT OF SPAIN, Trinidad, Thursday July 23, 2015 .
The UWI Seismic Research Centre (SRC) has heightened the alert level at underwater volcano Kick ‘em Jenny to orange – which means it could start erupting with less than a day’s warning – after strong, continuous signals were recorded in the early hours of this morning. In an advisory posted on its website and on social media, the centre said that from 1:25 a.m. to 3 a.m., a strong continuous signal was observed on instruments monitoring the submarine volcano which is located 8 km north of Grenada.
Signs of elevated seismicity (earthquakes) began on 11th July and continue to present. For the period since the 11th July a total of more than 200 micro and small earthquakes, of varying magnitudes, have been recorded, with the largest, prior to the strong signal, less than magnitude 3.0,” the Trinidad-based SRC reported.
It added that divers had also observed degassing occurring off the west coast of Grenada in the Moliniere Sculpture Park area.
“This activity is being closely monitored by the UWI-SRC and further updates would be issued as more information becomes available,” the centre said.An orange alert, according to the UWI-SRC website, is issued when there is highly elevated level of seismic and/or fumarolic activity or other unusual activity. In this case, eruption may begin with less than 24 hours’ notice.
The recommended action corresponding with that orange alert is for:
Vulnerable communities to be advised of evacuation routes and transport put on standby; all shipping to remain outside the first exclusion zone (1.5 km from the summit); and all non-essential shipping (pleasure craft, etc.) to stay 5 km clear of the summit (second exclusion zone). It is also recommended that local radio stations in Grenada, St. Vincent, Barbados and Trinidad be placed on alert and that residents monitor local radio stations for updates and visit the SRC website where possible.
The heightened activity at Kick ‘em Jenny comes amidst a week of earthquakes occurring to the northeast of Barbados.
In response to a question posted on its Facebook page last weekend, about whether there was any relation between those tremors and the underwater volcano, the SRC had said they were “not related at all”.
Kick ’em Jenny last erupted on December 4, 2001.
Kick ’em Jenny, a historically active submarine volcano 8 km off the north shore of Grenada, rises 1300 m from the sea floor. Recent bathymetric surveys have shown evidence for a major arcuate collapse structure that was the source of a submarine debris avalanche that traveled more than 15 km to the west. Bathymetry also revealed another submarine cone to the SE, Kick ’em Jack, and submarine lava domes to its south. These and subaerial tuff rings and lava flows at Ile de Caille and other nearby islands may represent a single large volcanic complex. Numerous historical eruptions, mostly documented by acoustic signals, have occurred at Kick ’em Jenny since 1939, when an eruption cloud rose 275 m above the sea surface. Prior to the 1939 eruption, which was witnessed by a large number of people in northern Grenada, there had been no written mention of Kick ’em Jenny. Eruptions have involved both explosive activity and the quiet extrusion of lava flows and lava domes in the summit crater; deep rumbling noises have sometimes been heard onshore. Historical eruptions have modified the morphology of the summit crater.
July 24, 2015. Kick ’em Jenny , Grenada .
Sources : GVP, caribbean360.com .