Friday, July 24, 2015

Grenada: Submarine Volcano Raised To Orange Alert

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Credit Wikipedia

 

 

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Although we tend to think of hurricanes as the greatest natural disaster threat in the Caribbean, earthquakes and volcanic eruptions have claimed hundreds of thousands of lives over the past 300 years.  The 2010 Haitian earthquake alone claimed 200,000+ lives, and the1902 eruption of Mount  Pelée on the northern end of the island  Martinique is believed to have killed as many as 30,000.


In 1995, a previously dormant volcano (Soufrière Hills ) on the island of Montserrat erupted and eventually buried the island's capital, Plymouth, in nearly 40 feet of mud and ash.  Although the damage was extensive, and half the island is now uninhabitable, there was enough warning to evacuate nearly all of the residents.


As we discussed last March, in The Caribbean’s Hidden Tsunami Potential (Revisited), the Caribbean has a long history of volcanic, seismic, and tsunami activity. 

 

One of the most active volcanoes of the past 100 years is a submerged seamount called Kick’em Jenny, which rises more than 4000 feet from the seafloor, yet its peak remains more than 500 feet below the surface.  

 

Between 1939 and 2001, at least 12 eruptions have been recorded, although many were so small to be only detectable by instruments.  It has remained pretty quiet for the past 14 years.

 


Yesterday, the Seismic Research Centre (SRC) of the University of the West Indies issued an Alert, and a statement, regarding increased seismic activity in and around Kick’em Jenny.  For now, this is just an Alert, and there is no immediate threat.

 

Changed Alert Level at Kick 'em Jenny Submarine Volcano


Jul.23.2015

On Thursday, July 23rd from 1:25am to 3:00am local time, a strong continuous signal was observed on instruments monitoring the Kick ‘em Jenny submarine volcano. 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. There have also been observations from divers of 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.

Please be advised

Current Alert Level: Orange

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No Tsunami Warning Issued

Jul.23.2015

The UWI-SRC wishes to advise that at this time no tsunami warning has been issued for Grenada or any other neighbouring islands of the Lesser Antilles. The alert level at the Kick ‘em Jenny volcano however, has been moved from yellow to orange which means that the exclusion zone around the submarine crater has been widened to 5km. This change of alert is in keeping with increased seismic activity which began on 11th July, 2015. A sharp increasing trend was observed during the 21st and 22nd July and between 1:25am and 3:00am on Thursday 23rd July, 2015 the most intense activity, an eruption was observed. The current alert level at Orange is related to the Kick ‘em Jenny volcano and guides authorities and those in Grenada and the surrounding Grenadine islands on what is appropriate at this level of activity. Mariners are therefore encouraged to observe the Exclusion Zone and not enter within a 5km radius of the Kick ‘em Jenny Crater. The UWI-SRC continues to monitor this volcano and will issue further updates as data come to hand.

 

The 1939 eruption – the largest observed – reportedly sent a plume of steam and debris several hundred meters into the air, and generated a moderate (2 meter) localized tsunami.  Large tsunamis are considered unlikely with a seamount volcano of this type and depth.

 

For an excellent description of the potential hazards – mostly to shipping and boating interests - you can visit the Seismic Research Centre’s:

Grenada - Kick `Em Jenny Hazards

Kick 'em Jenny is the source of a number of potential dangers. The most immediate and frequent danger is to marine vessels in the vicinity of the volcano during eruptions and during the 'quiet' periods between eruptions. The volcano lies directly beneath one of the main inter-island shipping routes and the area is popular both with recreational sailors and fishermen. For this reason Kick 'em Jenny is carefully monitored and a 1.5km exclusion zone around the summit of the volcano is currently in place. Although scientists continue to stress the improbability of an eruption generating a tsunami (a giant sea wave) this hazard also remains of great public concern.

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(Continue . . . )

  

The Government of Grenada has issued as statement urging calm, stating that this volcano does not pose any significant threat to the island’s residents.

 

Increased activity at Kick em Jenny poses no significant threat to Coastal Residents

 ST. GEORGE'S, GRENADA, July 23, 2015 - GIS: The Seismic Research Centre, University of the West Indies says that renewed activity at the Kick em’ Jenny under water Volcano just off Grenada represents no significant threat to the coastal regions of nearby islands.


As a consequence there is no need to move people away from coastlines.


Lloyd Lynch, researcher at the Trinidad-based Centre briefed disaster management officials in Grenada Thursday afternoon.


He told an emergency meeting of the National Emergency Advisory Committee at NaDMA Headquarters that more minor eruptions can be expected before the system goes back to sleep.


But he noted that the undersea volcano remains well below the surface, which cancels out any threat of a major tsunami.


Earlier, the Seismic Research Centre issued an orange alert regarding the status of the Kick ‘em Jenny Volcano.


Orange alert means highly elevated level of seismic activities consistent with the small tremors which have been occurring over the past two weeks.


Orange alert also means that all ships must stay outside the five kilometer exclusion zone of Kick ‘em Jenny.


Currently, the volcano is most dangerous for ships and boats since the gases released by Kick ‘em Jenny can lower the density of the water causing them to sink even if it is not erupting.


The Seismic Centre of the UWI is constantly monitoring the situation, and should there be a change in the current status, immediate advisories will be issued.


The people of Grenada should be careful to take note of only official advisories on the matter, which if needed, will come from the National Disaster Management Agency (NaDMA).


Please note that there was no need for panic, and people should go about their daily lives as normal.

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