Sunday, July 26, 2015

Kick 'em Jenny underwater volcano research

The Alert level was Orange yesterday and probably still is but hasn't been modified online yet likely.
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Skip Navigation LinksHome : Island Profiles : Grenada : Kick 'em Jenny
ISLAND PROFILES
Grenada - Kick `em Jenny

Alert level: YELLOW. A 5km exclusion zone is currently around the summit of the volcano.

What is Kick 'em Jenny?
Kick 'em Jenny is a submarine volcano located 8km north of Grenada. The volcano is about 1300m high, and its summit is currently thought to be about 180m below the surface of the sea. As far as we know, Kick 'em Jenny is the only 'live' (likely to erupt again) submarine volcano in the Eastern Caribbean. It is also the most frequently active volcano in the region, erupting at least 12 times since it was discovered in 1939. The last eruption of Kick 'em Jenny occurred in December 2001. For details of that eruption go to news archives. The volcano is currently at Alert Level YELLOW. The YELLOW alert level means that vessels should observe a 1.5 km exclusion zone. However, as a precautionary measure, the marine community is advised to continue observing the 5 km exclusion zone.
 
Alert Levels for Kick `em Jenny Volcano
Alert Level Symptoms Action by Scientists Recommended action by Civil Authorities and the Public
GREEN Volcano is quiet. Seismicity and fumarolic (steam vent) activity are below the historical level at the volcano. No other unusual activity detected. Maintain basic monitoring system. - Undertake public awareness campaigns. -Prepare evacuation plan for vulnerable areas. - Check the Seismic Research Unit website regularly for change in status. - Visiting scientists should submit a complete plan of their proposed activities to NERO, Grenada, for approval
YELLOW Volcano is restless: seismicity and/or fumarolic activity are above the historical level or other unusual activity has been observed or can be expected without warning. - Bring monitoring system to full capability. - Civil authorities will be alerted and commuinication system tested. - Intensify public awareness campaigns. - An exclusion zone of 1.5km from the summit of the volcano should be enforced for non-essential shipping. - Visiting scientists should ensure that the Sauteurs Observatory is manned throughout their visit (at their expense) and that the Observatory can contact their ship at any time. They must also be prepared to leave the exclusion zones immediately upon request.
ORANGE Highly elevated level of seismic and/or fumarolic activity or other unusual activity. Eruption may begin with less than twenty-four hours notice. - All regional governments alerted through Disaster Coordinators and Venezuelan diplomatic missions. - Sauteurs Observatory continuously manned. - Continuous communication with NERO. (GRENADA and St. Vincent and the Grenadines). - Summit area under continuous visual surveillance. - Scientists and emergency personnel within exclusion zones maintain continuous contact with the Observatory. - Vulnerable communities advised of evacuation routes and transport put on standby. - Local radio stations in Grenada, St. Vincent, barbados and Trinidad placed on alert. - Public listens to local radio continuously for updates and visits the Seismic Research Unit website if possible. -All shipping stays outside the first exculsion zone (1.5km from the summit). - Non-essential shipping (pleasure craft etc) stays 5km clear of the summit (second exclusion zone). - Visiting scientists who are not taking part in essential monitoring are regarded as non-essential.
RED Eruption is in progress or may begin without further warning. - Measurements within the exclusion zones as permitted by activity. - Aerial reconaissance whenever possible. - Vulnerable areas prepared for immediate evacuation. - All shipping stays 5km clear of summit (i.e. out of the first and second exculsion zones). - Public in all vulnerable zones should listen to local radio stations for updates.
 
 
Kick 'em Jenny is also a modern day demonstration of how the volcanic islands in this region were formed. With each submarine eruption deposits of volcanic material accumulate around the summit. All of the volcanic islands of the Lesser Antilles began as submarine volcanoes.

Surtsey Island in Iceland formed in 1963 when a submarine volcano reached the surface of the sea. Eventually, Kick 'em Jenny will form a new island in the southern Grenadines.

How deep is Kick 'em Jenny?
Between the 1960's and the late 1970's the depth to the summit of the volcano was approximately 180-190m. In the 1970's and early 1980's the depth to the summit of the volcano decreased to approximately 150m, reflecting the growth of a dome within the crater. This dome was destroyed during eruptions in the late 1980's and a survey conducted by the U.S.-based National Oceanic and Atmospheric Administration (NOAA) in March, 2002 revealed that the summit is currently 180m below the surface of the sea.

Until recently it was thought that Kick 'em Jenny had grown 46m (from 236m to 190m below sea level) between the surveys of 1962 and 1966. However, data collected from the two most recent cruises (March 2002 and March 2003) and a careful re-examination of data collected on even earlier cruises make it clear that the crater rim of Kick 'em Jenny has remained at the same depth below the surface (180-190m, within measurement uncertainty) since at least 1966. The major sequence of changes over the past forty years has been that a dome grew in the crater between 1976 and 1978. This dome collapsed in either 1988 or 1990 and there is now no trace of it left. There is in fact a new interior crater about 30 metres deep on the site where the dome used to be so it is more accurate to say that the active vent area of Kick 'em Jenny has in fact become deeper. Kick 'em Jenny has, therefore, NOT grown closer to the surface between 1962-2003


SeaBeam image of Kick 'em Jenny showing new craters and domes (March, 2003). During a research cruise in March 2003 scientists discovered three craters (C1, C2 and Kick 'em Jack) and two domes (D1 and D2) near Kick 'em Jenny. Further investigations are needed to confirm whether these are separate 'live' volcanoes.

Until recently it was thought that Kick 'em Jenny had grown 46m (from 236m to 190m below sea level) between the surveys of 1962 and 1966. However, data collected from the two most recent cruises (March 2002 and March 2003) and a careful re-examination of data collected on even earlier cruises make it clear that the crater rim of Kick 'em Jenny has remained at the same depth below the surface (180-190m, within measurement uncertainty) since at least 1966. The major sequence of changes over the past forty years has been that a dome grew in the crater between 1976 and 1978. This dome collapsed in either 1988 or 1990 and there is now no trace of it left. There is in fact a new interior crater about 30 metres deep on the site where the dome used to be so it is more accurate to say that the active vent area of Kick 'em Jenny has in fact become deeper. Kick 'em Jenny has, therefore, NOT grown closer to the surface between 1962-2003.

Where is Kick 'em Jenny?

Kick 'em Jenny is located approximately 8km north of Grenada (12.18 degrees North, 61.38 degrees West). This location is in the southern part of the Grenadine Islands which are themselves in the southern part of the Lesser Antilles island arc (see Map 1 below). The volcano should not be confused with the nearby Diamond Rock, which is also called 'Kick 'em Jenny' on some charts.

On land the location is clearly visible from northern Grenada. From Sauteurs look towards the Île de Ronde. West - i.e. to the left - of the Île de Ronde is a small group of rocks called The Sisters. Kick 'em Jenny is 1.6 nautical miles (about 3 km) due west of the Sisters or about as far west of the Sisters as the Sisters are of the Île de Ronde. Marine vessel operators may click here for additional yachting information.


Map 1. Location of Kick 'em Jenny in the southern Grenadines.

Map 2. Kick 'em Jenny is 8km north of Grenada.

SeaBeam Image
The image below is a SeaBeam image of Kick 'em Jenny constructed from measurements taken from the NOAA Research Vessel Ronald H. Brown between 12th-21st March, 2003. The crater of Kick 'em Jenny is clearly visible just to the right of the centre of the image on top of a symmetrical cone. The crater is almost perfectly circular and has a diameter of approximately 350m. The centre of the crater is at 12.3004 degrees North 61.6378 degrees West. The highest point on the crater rim is at 61.6398 degrees West 12.3004 degrees North and is 180m below sea level.

The dome, which was first noticed in 1978 and almost completely filled the crater up to at least 1985 has now disappeared completely. The depth from the highest point of the crater rim to the lowest point of the crater floor is about 80m. The crater is breached to the northeast and contains an interior crater about 30m deep. The summit sits within a much bigger horseshoe-shaped depression which extends at least 20km to the west of Kick 'em Jenny and widens from about 5km to 10km. The depression contains a sequence of debris-flow deposits.

Complete interpretation of the data is still in progress. The interpretations here are preliminary and should not be quoted or reproduced elsewhere
(See Disclaimer).


SeaBeam image of Kick 'em Jenny. March, 2003 end quote from:http://www.uwiseismic.com/general.aspx?id=27
 

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