Update – July 26, 2015: The UWI Seismic Research Centre has downgraded the level of alert for Kick’em Jenny to yellow, following significant reduction in seismic activity at the volcano.
BRIDGETOWN — The Seismic Research Centre (SRC) of the University of the West Indies (UWI) has issued an orange alert for the underwater volcano Kick’em Jenny, after strong and sustained signals were recorded in the early hours of this morning, suggesting than an eruption could occur with less than 24-hours notice.
Instruments monitoring the volcano, located 8km north of Grenada (12.3000° N, 61.6400° W), recorded strong, continuous activity between 1:25 a.m. and 3.a.m this morning.
In a media statement issued today, the SRC said that signs of elevated seismic activity began on July 11, and have continued since then. “For the period since July 11, 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 SRC reported. “This activity is being closely monitored by the UWI-SRC and further updates will be issued as more information becomes available,” the statement continued.
Also speaking to the media today, Director of the Coastal Zone Management Unit in Barbados, Dr Lorna Innis, reassured residents of the island that the probability of a tsunami following the possible eruption of Kick’em Jenny was low – but not non-existent. Said Dr. Innis, the chances of a tsunami generation from an underwater volcano increased the closer the volcano’s dome was to the surface of the water, unlike Kick’em Jenny, which is believed to be located at a depth of 268m under water.
“An eruption [of Kick ‘em Jenny] can cause a tsunami, but we are dealing with possibilities. The dome of the volcano is in extremely deep water at this stage. As the dome grows… and it grows extremely slowly over decades and centuries… it moves closer to the surface of the water, and the greater the probability that when it erupts you will have a tsunami. At this point in time it is rather low as it is in extremely deep water and therefore the possibility of a tsunami is low,” she stated.
What does an orange alert mean?
At the orange alert level, the SRC recommends that the governments of Grenada, St. Vincent, Barbados and Trinidad & Tobago should advise residents of evacuation routes, and put transportation on standby to facilitate evacuation in the event of a tsunami.
Maritime exclusion zones
Shipping vessels should stay 1.5 km from the summit of Kick’em Jenny, and non-essential shipping, such as pleasure craft, should not enter within 5 km of the volcano’s summit. An eruption, or increased activity around Kick’em Jenny, is particularly dangerous for marine vessels, since the gases released from the volcano can lower water density and can cause ships to sink.
Kick’em Jenny last erupted on December 4, 2001 – the time of the last orange alert issue – and it has erupted twelve times since 1939.
Authorities in Barbados have reiterated that no tsunami watches or warnings have been issued, and they continue to urge calm in light of today’s announcement. Similarly, in Grenada and Trinidad & Tobago, authorities there have been advised that there was no need to move residents from coastal areas.
Update (July 24, 2015 @ 2302 hrs): The orange alert status remains in effect for Kick’em Jenny, and seismic activity around the volcano has continued, with the SRC confirming that there was a second, small eruption of the volcano just after midnight on July 24.
UWI SRC has however reiterated that the chance of a tsunami being generated by an eruption of the volcano was low, and that the more-immediate concern was the impact of the volcanic activity on shipping. SRC therefore continues to urge marine vessels to observe the exclusion zones.
“From time to time, Kick ‘em Jenny has periods of increased seismicity. Eruptions are most often confined below the surface of the ocean and have not affected surrounding areas but it is always possible that magnitude could increase and eruptions could break the surface”, said Dr. Richard Robinson, Director of the SRC.
“Activity at Kick ’em Jenny is following similar patterns to what has occurred in the past where you’ve had increased seismicity followed by some sort of eruptive activity. The most common thing it does is that it goes back quiet again until the next time it happens. Since 1935, Kick ’em Jenny has had on average one episode like this every 10 years and the last time it happened was 2001, so we were expecting in a sense that something would happen within the next couple years. In fact, it’s a bit overdue so this is not unusual in that sense,” he added.
Despite reassurances, the Queen Elizabeth Hospital in Barbados has taken the precautionary measure to relocate its Accident & Emergency Department – a move which management said was aimed at ensuring that its services were not compromised in the event of a disaster.
Fibre optic cables supporting internet and mobile data for residents in Grenada and Trinidad & Tobago were also affected by the increased seismic activity, leading to slower-than-usual data speeds.
Update (July 25, 2015 @ 1556 hrs): Since 4:00 p.m. 24th July to 6:30 a.m. 25th July, there have been less than 20 earthquakes associated with the Kick-‘em-Jenny system. This represents a significant decline in the level of earthquakes associated with the activity so far. The SRC will continue to monitor throughout the day to develop a better understanding of the current state of the system.
Image credit: Wayne Hsieh