Showing posts with label Trinidad and Tobago. Show all posts
Showing posts with label Trinidad and Tobago. Show all posts

Saturday, 17 February 2024

Oil spill on the coast of Tobago, following wreck of mystery barge.

An oil slick has spread over 160 km on the Caribbean Sea following the wreck of a barge off the coast of the island of Tobago on 7 February 2024. The wreck was not reported by the barge's owners, but instead was spotted by beachgoers who reported it to the Tobago Emergency Management Authority. The barge has capsized on Cove Reed, off the southern coast of the island, and oil from it has spread over reefs and beaches along the southern tip of the island, as well as spreading across the Caribbean Sea towards Grenada and Venezuela.

An aerial image of the capsized barge. Office of the Chief Secretary of Tobago.

The barge appears to have been an unmanned and unpowered vessel, and has the word 'Gulfstream' painted on its side. As an unmanned, unpowered vessel it would not have been required to register with the International Maritime Organization, nor to carry an Automatic Identification System tracker, although it would have been partnered with a manned tugboat, which should (in theory) have complied with both of these requirements.

Before and after satellite images from the Copernicus Sentinel-1 mission show the scale of the oil spill that occurred off the shores of Trinidad and Tobago’s coastline earlier this week. The vessel, identified as the Gulfstream, ran aground and overturned off the southern shores of Tobago Island. The final image of the animation, captured at 10.18 pm GMT on 14 February, shows the oil spill has travelled over 160 km westwards. The spill is moving out of Trinidad and Tobago’s marine area and into Grenada’s southernmost marine area – which could affect neighbouring Venezuela. Satellite radar is particularly useful for monitoring the progression of oil spills because the presence of oil on the sea surface dampens down wave motion. Since radar basically measures surface texture, oil slicks show up well – as black smears on a grey background. European Space Agency.

An investigation by the Trinidad and Tobago Coast Guard found that a barge identified as the Gulfstream left Panama en route for Guyana coupled to a tug called the Solo Creed on 12 January 2024, and that authorities in Guyana reported that neither vessel arrived there. The Solo Creed, identified by the Vessel Finder website as a Tanzanian registered towing vessel, which visited Aruba on 20 January, and was last detected off the coast of Venezuela on 4 February.

An image of the capsized barge on 10 February 2023. Tobago House Assembly/AFP.

The Bellingcat investigative agency has identified a double-hulled barge capable of carrying 60 000 barrels of oil (i.e. 9.5 million litres) called the Gulfstream which was coupled to a tugboat called the Marlin, operating within the United States until 2012, which appears to be a good physical match for the vessel off the coast of Tobago. The Marlin was sold to the Panamanian San Martin Group in 2014, and while there are no official records of the Gulfstream after this, Bellingcat has found photographic evidence of the two vessels operating together between Panama and Venezuela between 2015 and 2020. The Marlin was sold on to another Panamanian company, Star Goods Petroleum, in 2021, and has not transmitted its position since. The Gulfstream was observed in the Astinave shipyard in Ecuador in February 2022, but has not been sighted since. Bellingcat suspect that the renamed Marlin and Gulfstream may still be operating together, as part of a 'ghost fleet' carrying embargoed Iranian oil to Venezuela. Many oil-carrying vessels operating out of Venezuela are considered to be poorly maintained to the point of being dangerous, and the Marlin and Gulfstream, if still operating together, would be 60- and 58-years-old respectively; both vessels would have been built with a planned lifetime of 30 years.

Oil spills are potentially harmful to marine life in a variety of ways. Most obviously it can coat the outside of organisms, causing damage to external structures such as the feathers of Birds and fur of Mammals, as well as smothering many marine invertebrates and plants. It also contains a variety of chemicals which can be directly toxic upset the hormonal balance of many animals. Oil also impedes the feeding of marine organisms, coating both food and feeding organs, but provides an excellent food source for Bacteria, which can lead to Eutrophication events - dramatic increases in Bacteria numbers, which then use all the oxygen in the water, leading other organisms to asphyxiate.

Workers from state own Heritage Petroleum Oil and Gas Company, the state oil company of Trinidad and Tobago, clean up an oil spill that reached Rockly Bay beach, in Scarborough, south western Tobago. Akash Boodan/AP.

Many fishermen on the southern part of Tobago are reporting vessels and equipment damaged by exposure to oil, and beaches across the southern part of the island being forced to close to tourists at the height of the tourist season. Volunteers and local specialists have recovered about 2000 barrels of oil from beaches on Tobago, but the vessel is still leaking and will probably need to be emptied of oil before it can be refloated and the damage repaired.

See also...

Monday, 5 October 2020

Magnitude 4.2 Earthquake to the north of Trinidad.

The United States Geological Survey recorded a Magnitude 4.2 Earthquake at a depth of 51.5 km roughly 30 km to the north of Trinidad, slightly after 3.10 pm local time (slightly after 7.10 pm GMT) on Sunday 4 October 2020. This was a moderate quake, but at some depth as well as some way offshore, and there are no reports of any casualties or serious damage, though the quake was felt over a large area, with people reporting feeling it across much of Trinidad, Tobago, and Grenada.

 
The approximate location of the 4 October 2020 Trinidad Earthquake. USGS.

The southern margin of the Caribbean Plate lies just off the northern coast of Venezuela, cutting through the middle of the island of Trinidad, this is moving eastward compared to the South American Plate, upon which most of Venezuela sits. This is not a smooth process, the two plates constantly stick together, then break apart as the pressure builds up, causing Earthquakes in the process. 
Geologic map of Trinidad. Abbreviations: Q, Quaternary; Cz,  Cainozoic; Mz, Mesozoic; Note: Qf (Quaternary fan deposits) are buried in the west by Qal (Quaternary alluvium) of the Caroni swamp, and in the east are exposed and highly dissected by modern streams. Weber 2009.
 
Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.

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Tuesday, 7 April 2020

Magnitude 5.2 Earthquake between Tobago and Grenada.

The United States Geological Survey recorded a Magnitude 5.2 Earthquake at a depth of 31.0 km roughly half way between the islands of Tobago and Grenada,  slightly after 11.25 pm local time on Monday 6 April 2020 (slightly after 3.25 am on Tuesday 7 April GMT). There are no reports of any casualties or damage associated with this event, though the quake was felt over a large area, with people reporting feeling it across Tobago, Grenada, Trinidad, and St Vincent and the Grenadines.

The approximate location of the 6 April 2020 Tobago and Grenada Earthquake. USGS.

The Lesser Antilles Islands, including Grenada and Tobago are located at the eastern fringe of the Caribbean Tectonic Plate. The Atlantic Plate (strictly speaking, an extension of the South American Plate which runs to the northeast of the Caribbean) is being subducted beneath this, and as it sinks into the Earth, is melted by the heat of the planets interior. Some of the melted material then rises up through the overlying Caribbean Plate as magma, fuelling the volcanoes of the Lesser Antilles Volcanic Arc. The subduction of the Atlantic Plate beneath the Caribbean Plate is not a smooth process, with the two plates constantly sticking together then breaking apart as the tectonic pressure builds up, causing Earthquakes in the process, though since the boundary between the two plates is some way to the east of the islands, Earthquakes in the Lesser Antilles tend to be both deep and offshore, which lessens their destructive potential.

 The subduction of the Atlantic Plate beneath the Caribbean Plate fuels the volcanoes of the Lesser Antilles Volcanic Arc. George Pararas-Carayannis.

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The University of the West Indies is interested in hearing from people who have felt Earthquake events in the region; if you felt such a quake then you can report it here. 

See also...

https://sciencythoughts.blogspot.com/2018/09/magnitude-54-earthquake-to-northeast-of.htmlhttps://sciencythoughts.blogspot.com/2018/04/magnitude-47-earthquake-beneath-western.html
https://sciencythoughts.blogspot.com/2018/03/warning-issued-to-shipping-after.htmlhttps://sciencythoughts.blogspot.com/2018/02/magnitude-52-earthquake-to-north-of.html
https://sciencythoughts.blogspot.com/2017/12/magnitude-52-earthquake-to-northeast-of.htmlhttps://sciencythoughts.blogspot.com/2017/09/magnitude-46-earthquake-to-northeast-of.html
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