Showing posts with label Sri Lanka. Show all posts
Showing posts with label Sri Lanka. Show all posts

Sunday, 7 December 2025

Number of dead in Sri Lanka following Cyclone Ditwah has now reached 619.

The number of people known to have died after Cyclone Ditwah made landfall in Sri Lanka on 28 November 2025 has reached 219, making the storm the worst natural disaster to befall the nation since the Boxing Day Tsunami of 2004. A further 209 people are still recorded as missing since the storm, with 18 people listed as having been injured. About 2 million people (almost 10% of the population) are thought to have been affected in some way by the storm, with 4071 homes destroyed and 71 121 damaged by flooding and landslides, as has much of the island's infrastructure and agricultural land. Authorities in Sri Lanka are warning that there is still a high risk of landslides, as monsoon rains fall onto already soaked hillside soils. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall.

Flooding in the Gampaha District of Colombo, Sri Lanka, following the passage of Cyclone Ditwah. Incept Change/UNICEF

Cyclone Ditwah was first detected as a tropical depression off the south coast of Sri Lanka by the Indian Meteorological Department on 26 November 2025. This depression increased in strength, becoming first a deep depression and then a cyclonic storm of 27 November. It crossed over Sri Lanka on the night of 28-29 November, bringing catastrophic levels of rainfall, then moved out over the Bay of Bengal. The storm continued to move northwatds along the Coromandel Coast, in the process bringing more flooding to the states of Tamil Nadu and Puducherry, which led to three Human and 149 Cattle deaths, as well as flooding much farmland, and damaging or destroying 234 homes. The storm weakened as it moved northward, eventually making landfall in Tamil Nadu as a low pressure system on 3 December.

Flood damage beside the Mahaweli River in Kandy, Sri Lanka, following the passage of Cyclone Ditwah. Reuters.

Tropical storms are caused by the warming effect of the Sun over tropical seas. As the air warms it expands, causing a drop in air pressure, and rises, causing air from outside the area to rush in to replace it. If this happens over a sufficiently wide area, then the inrushing winds will be affected by centrifugal forces caused by the Earth's rotation (the Coriolis effect). This means that winds will be deflected clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere, eventually creating a large, rotating Tropical Storm. They have different names in different parts of the world, with those in the Indian Ocean being referred to as cylcones.

The structure of a tropical cyclone. Wikimedia Commons.

Despite the obvious danger of winds of this speed, which can physically blow people, and other large objects, away as well as damaging buildings and uprooting trees, the real danger from these storms comes from the flooding they bring. Each drop millibar drop in air-pressure leads to an approximate 1 cm rise in sea level, with big tropical storms capable of causing a storm surge of several meters. This is always accompanied by heavy rainfall, since warm air over the ocean leads to evaporation of sea water, which is then carried with the storm. These combined often lead to catastrophic flooding in areas hit by tropical storms. 

The formation and impact of a storm surge. eSchoolToday.

Cyclone Ditwah is not considered to be a large storm, but has caused extensive damage due to the large volumes of water it dropped onto Sri Lanka. It has been estimated that the cost of repairing the infrastructure damage caused by the storm will be about US$7 billion, coupled with a loss of income from the destruction of the agricultural and tourism sectors. Sri Lanka had a gross domestic product of about US$99 billion in 2024, but suffers from high levels of government debt. In 2023 the country was obliged to borrow US$3 billion from the International Monetary Fund to help with debt servicing, after a period of economic contraction in 2022 which led inflation to reach 57%. 

Sri Lanka is considered to have met the first United Nations' Millennium Development Goal, halving extreme poverty between 1990 and 2015, but 12% of the country is still considered to be living below the extreme poverty line, and 53% below the poverty line. While the country has made progress on growing its economy and lifting its people out of poverty, climatic events such as Cyclone Ditwah can set progress back significantly, and are predicted to become more common as the climate warms. Countries in the Global South are predicted to be particularly badly impacted by effects of global warming, despite having done little to cause the crisis; Sri Lanka is considered to have produced about 0.03% of global greenhouse gas emissions since the onset of the Industrial Revolution.

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Sunday, 7 April 2024

Looking for the origins of garnets from Lower Nubia.

From about the third century BC, garnets became highly valued gemstones to the peoples of the Mediterranean Basin, the Middle East, India, Sri Lanka, Southeast Asia, and China, along with other hard gemstones, such as emerald, aquamarine, and sapphire. Transparent red garnet was used to make engraved rings or seal stones; inlays in diadems; earrings or necklaces or even small sculptures; thin, doubly polished plates in cloisonné jewellery, as well as simple beads, merely drilled to be assembled into necklaces, bracelets, or applied to garments. Studies of garnets dating from the Hellenistic Period to Early Medieval times have identified seven distinctive garnet types (A-G), with unique compositions, some of which have been linked to sources in Europe, India, or Sri Lanka, while the source of others remains unknown.

Garnets were also used as gemstones prior to the Hellenistic Period in several places, although the origin and typology of these is less well understood. Green grossular, a calcic garnet, often intergrown with green vesuvianite was used to make seals, beads, and amulets by the Indus Valley Civilization, and to much lesser extent in ancient Mesopotamia. This material was worked in Harappa, Mohenjo-Daro, and Loal-Mari on the Indus River, and was probably sourced in Balochistan and northern Pakistan. Both grossular and vesuvanite have hardnesses of between 6.5 and 7.0 on the Moh scale (i.e. are slightly softer than quartz) making it possible to work these materials with the tools available to the Indus Valley Civilization.

Red aluminous garnet, however, is harder than quartz, making it much more difficult to work without specialist tools, and is rare in Asia before the advent of the Iron Age. Surprisingly, this material was worked early in Northeast Africa, with red garnet beads known from Predynastic Egypt and the contemporaneous A-group Cultures of Lower Nubia. The use of red garnet continued in Egypt till around the end of the New Kingdom, after which the mineral is seldom found. Thus, the red garnets of Egypt and Nubia are the oldest known examples of the working of this mineral.

In a paper published in the journal Archaeometry on 7 March 2024, Albert Gilg of Engineering Geology at the Technical University of Munich, Joanna Then-Obłuska of the Antiquity of Southeastern Europe Research Centre at the University of Warsaw, and Laure Dussubieux of the Elemental Analysis Facility at the Field Museum, present the results of an analysis of 34 garnet beads from burials in Lower Nubia, dated from the late A-Group to the Post-Meroitic, an age range of about 3200 BC to about 600 AD, as well as two garnets from separate alluvial deposits near the Fourth Cataract of the Nile in the Bayuda Desert of Upper Nubia.

Ancient Nubia is divided into Lower Nubia, which lay between the First and the Second Cataracts of the Nile, and Upper Nubia, to the south of the Second Cataract. Gilg et al. selected beads excavated  from graves in Qustul, Adindan, and Serra East, in the collection of the Museum of the Institute for the Study of Ancient Cultures at the University of Chicago, associated with the Early Nubian A-group Culture, the Middle Nubian C-group and Pan Grave cultures, and the New Kingdom, Napatan, Meroitic, and Post-Meroitic/Nobadian periods.

The A-group Culture (roughly 3700 to 2800 BC) and C-group Culture (roughly 2300 to 1550 BC) are known to have been wealthy societies, due to their location at a junction of trade routes between Egypt and the Mediterranean to the north and the African interior to the south. The Pan Grave people (2200 to1550 BC) lived in small, dispersed groups in the Eastern Desert. All of these peoples traded to differing extents with the Pre-Kerma and Kerma cultures of Upper Nubia. Between about 1570 and about 1069 BC Nubia was controlled by the Egyptian New Kingdon, then between 747 and 656 BC, Egypt was ruled by the Kushite 25th Dynasty, which ruled an area from the confluence of the Blue and White Niles to the Mediterranean. This interval forms part of the Napatan Period in Nubia, which lasted from about 750 BC to about 350 BC, and was another period of wealth in Lower Nubia. This was followed by the Meroitic Period, from about 350 BC to about 350 AD, when Lower Nubia became an intermediary in trade between the Kingdom of Meroë in Upper Nubia and the Hellenic and Roman rulers of Egypt. Between about 350 and 600 AD Lower Nubia was Kingdom of Nobadia, which often had less peaceful relations with both Egypt and the Blemmye peoples who controlled the Eastern Desert and the Red Sea Coast.

Map of Nubia. Gilg et al. (2024).

Gilg et al. analysed garnet beads from tombs 11, 17, 22, 24 of Royal Cemetery L at Qustul, which have been dated to Late A-Group/Naqada III (Naqada III is the final phase of Predynastic Egypt), as well as the late A-Group tombs W19 and V59; garnets from these tombs were commonly accompanied by similarly shaped carnelian beads. Another bead was from the  C-Group Phase III tomb T12B at Adindan, which is of equivalent age to the Egyptian 18th Dynasty (the first dynasty of the New Kingdom). Five more beads come from tombs K74 and K93 at Adindan, which were associated with the Pan Grave Culture; notably, garnet beads are more common in Pan Grave Culture burials than C-Group Culture burials, despite the two being roughly contemporary. Six more beads came from New Kingdom tombs VC45 and R19 at Qustul, three from the Amenhotep III to Amarna Period and three from the post-Amarna Period. A single short barrel bead came from the 25th Dynasty/Napatan tomb W43 at  Qustul. Also from Qustul came an oblate bead from the Meroitic tomb Q465, and a truncated hexagonal bicone bead from the Post-Meroitic tomb Q143.

Beads associated with the A-Group culture are all less than 5 mm in diameter and 2.5 mm wide. They were shaped into short cylinders, barrels, or oblates with a relatively poor polish, and perforated from each end by irregular pecking. Similar beads are known from Predynastic Upper Egypt, which were presumably made in the same way, possibly from the same people. A single bead of similar appearance has also been found at Mehrgarh in Pakistan, which is exotic to that site, but of unknown origin. C-Group and Pan Grave Culture beads are also typically poorly polished and of imperfect shape, though the shape varied slightly, with both rounded and short-barrel beads found. These beads were perforated from each end by drilling, forming either cylindrical or conical holes; the smooth nature of the hole suggests the drill made from a hard stone, such as flint, or possibly copper. Similar perforations have been observed in Middle Kingdom garnet beads from Egypt. Workshops producing carnelian beads are known from A-Group and C-Group sites in Lower Nubia, and while no trace of garnet-working has been found at these sites, the similarity between the carnelian and garnet beads suggests that the garnet beads are also likely to have been manufactured locally.

Microphotographs of garnet beads from lower Nubia. (a) A-group bead with irregular pecked hole (ISAC 13); (b) Pan Grave bead with a smooth drilled hole (ISAC 21); (c) C-group bead with silver beads (ISAC 20);  (d) New Kingdom long barrel-shaped beads with poor polish (ISAC 29-31); (e) Meroitic irregular oblate bead (ISAC33); (f) Post-Meroitic facetted bead (ISAC 34); (g) drill hole (about 1 mm in diameter) with concentric deep grooves from a diamond tipped drill (ISAC 34); (h) tiny short- and long-prismatic colourless inclusions (ISAC 34). Scale bar is 500μm. Gilg et al. (2024). 

The New Kingdom beads showed much improved shaping. The majority of these beads were globular in shape, but also present were unusually long barrel to tubular shapes with a length of up to 7.9 mm and a diameter of 4 mm. These beads all have a low polish, and again are drilled from both ends. The Napatan and Meroitic beads were similar in form to the Pan Grave and C-Group beads.

None of these beads had a high polish, something seen in Egyptian beads from the Great Aten temple at Amarna (18th Dynasty), which were made by polishing with corundum powder as an abrasive, a technique apparently unknown in Upper Nubia. How the Upper Nubian beads were polished is unclear at this time.

The youngest, Post-Merotic bead differs from all others in the study, having a faceted shape (a hexagonal truncated bicone), a well-polished surface, and deep, regularly spaced, concentric grooves in the drill hole, probably indicative of the use of a diamond drill bit. Similar garnet beads are known from Arikamedu in southern India, and sites in southern Sri Lanka. Microscopic examination of this bead revealed the presence of many tiny, short- and long-prismatic, colourless inclusions, something seen in Sri Lankan garnets but not garnets from southern India. Though this is not sufficient evidence to confirm the origin of this bead, Gilg et al. consider it highly likely that this bead comes from South Asia, and probably Sri Lanka.

Chemically, all of the garnets, including the alluvial samples from Upper Nubia were found to be of similar composition, with the exception of the single Post-Merotic bead. These beads have an almandine-rich composition, with a low calcium content (the Post-Merotic bead has a pyrope-rich composition with a low calcium content). Compositionally, these beads do not fit into any of the types used to classify Hellenistic to Early Medieval garnets, with magnesium oxide-calcium oxide ratios intermediate between type A and type B contents, combined with a high manganese and yttrium, low chromium composition not seen in either of these types. This suggests that the beads were made from alluvial garnets sourced from deposits in Upper Nubia, and that garnets from this source were not used in the Hellenistic to Early Medieval periods.

Almandine-rich garnet was the first mineral harder than quartz to be worked in northeast Africa, apparently being sourced at a site in the Bayunda Desert of Upper Nubia at least 670 km south of the most southerly known occurrence of worked garnet beads in Lower Nubia. These Upper Nubian deposits appear to have been the only source of garnets used in manufacturing for at least 3500 years. 

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Thursday, 5 November 2020

About 120 Short-finned Pilot Whales returned to the sea following mass stranding in Sri Lanka.

About 120 Short-finned Pilot Whales, Globicephala macrorhynchus, have been returned to the sea, following a mass stranding event. The Whales began to wash up on a beach near Panadura, on the southwest coast about 25 km to the south of the capital, Colombia, on Monday 2 November 2020. Volunteers from the local community, joined by members of the country's Navy and Coast Guard, immediately began work to return the Whales to the sea, with most of the Animals thought to have been returned safely, although at least four have known to have died.

 
A Short-finned Pilot Whale, Globicephala macrorhynchus, that died following a mass stranding event in Sri Lanka on 4 November 2020, one of four Whales known to have died as a result of the incident. Lakruwan Wanniarachchi/AFP/Getty Images.

Short-finned Pilot Whales, Globicephala macrorhynchus, are considered to be of Least Concern under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species, with a global population of over 700 000 individuals, split into four distinctive populations, two in the Pacific and one each in the Indian and Atlantic oceans. They typically live in pods of eight to ten individuals, but sometimes assemble into larger groups, sometimes with many hundreds of individuals congregating at the same location. However, this behaviour can make these Whales vulnerable to mass strandings, if large gatherings become spooked or disorientated by some event. The actual causes of such strandings are unclear, with a variety of causes having been suggested, including naval sonar, soar activity, and anomalies in the Earth's geomagnetic field.

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Friday, 4 September 2020

Burning oil tanker off the coast of Sri Lanka raises concerns of potential new pollution event in the Indian Ocean.

Concerns are being raised about the possibility of a major new pollution incident in the Indian Ocean originating from a burning oil tanker off the coast of Sri Lanka. The Panamanian-registered, Liberian-owned MT New Diamond, classified as aa Very Large Crude Carrier, suffered an explosion in its engine room on Thursday 3 September 2020, in which one crew member, described as a Philippine national, died. Since then the remaining 22 members of the crew, all Greek and Philippine nationals, have been evacuated, but fire-fighting  and rescue teams from the Sri Lankan Navy, Indian Navy, Indian Coast Guard, Indian Air Force, and Russian Navy have been unable to contain a fire on board the ship that resulted from the explosion. A small amount of oil has been sighted leaking from the ship, and a 2 m crack has been seen in the hull, though at the current time this is above the water. The vessel is currently about 65 km off the coast of Sri Lanka, and being towed further away, but there are concerns that if the fire cannot be brought under control, or the majority of the 2 million barrels (318 million litres) of crude oil on board removed safely, then the incident could present a major threat to the beaches of southern India, Sri Lanka, and the Maldives.

 
The MT New Diamond, currently on fire off the coast of Sri Lanka. EPA.

The MT New Diamond is owned by the Monrovia-based Porto Emporios Shipping Inc., but had been chartered by the Indian Oil Corporation to ship Kuwait Export Crude from the port of Mina Al Ahmadi in Kuwait to the Indian port of Paradip, where the Indian Oil Corporation has a refinery capable of processing 300 000 barrels of crude oil per day. Like many such vessels it is registered in Panama, home to the world's largest shipping registry. Panama has long been accused of having exceptionally lax shipping regulations, and recent incidents involving Panama-registered ships in harbours or close to shores in Lebanon, the Yemen, Venezuela, and Mauritius, have led to widespread criticism of the registry even within the shipping industry.

 
Fire burning aboard the MT New Diamond on 3 September 2020. Indian Navy.

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.

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Wednesday, 15 January 2020

Chinese national arrested trying to smuggle Scorpions through Bandaranaike International Airport, Sri Lanka.

A 30-year-old Chinese man was arrested at Bandaranaike International Airport in Colombo, Sri Lanka when he was found to be carrying about 200 live Scorpions in plastic containers in his luggage. The man admitted to having collected the animals from the wild himself, and stated that he was taking them back to China for breeding and to sell. He was eventually allowed to continue his journey, without the Scorpions, after paying a 100 000 rupee fine (about US$550).

Scorpions found in the luggage of a Chinese man detained at Colombo Airport, Sri Lamka. Colombo Gazette.

Sri Lanka has a high biodiversity level, with many endemic species (species not found anywhere else), as might be expected from a large island in a tropical location, It has in theory had legislation to protect its wildlife for decades, but a lengthy civil conflict has made this less of a priority than it might have been, and the country became a centre for wildlife crime, with criminals both targeting the island's own flora and fauna, and using the island as a rout through which to smuggle wildlife and wildlife products from elsewhere in Asia and Africa. The country has stated that it now intends to make tackling wildlife crime a priority, though with a large, and growing population, high poverty levels, and a weak national infrastructure, it remains to be seen how this will be implemented.

See also...

https://sciencythoughts.blogspot.com/2018/08/alloscorpiops-viktoriae-new-species-of.htmlhttps://sciencythoughts.blogspot.com/2018/02/physoctonus-amazonicus-new-species-of.html
http://sciencythoughts.blogspot.co.uk/2016/04/opsieobuthus-tungeri-scorpion-from.htmlhttp://sciencythoughts.blogspot.co.uk/2015/08/tityus-apozonalli-new-species-of.html
http://sciencythoughts.blogspot.co.uk/2015/05/scorpiops-ingens-new-species-of.htmlhttp://sciencythoughts.blogspot.co.uk/2014/08/two-new-species-of-scorpion-from.html
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Friday, 19 July 2019

Shopkeeper killed and businesses destroyed by landslide in Central Province, Sri Lanka.

At least one person has died and around ten small businesses have been completely destroyed following a landslide that hit the town of Ginigathhena in the Nuwaraeliya District of Central Province, Sri Lanka, on the morning of Friday 19 July 2019. The dead man has been identified as Kaldeen Mohamed Jamaldeen, 64, the owner of an electrical appliance shop. The businesses lost are reported to include several grocery stores, vegetable stalls, two restaurants, a salon and a shop selling ornaments. The area had previously been identified as being at a high risk of landslides by the Sri Lankan National Building Research Organisation, which recommended the area be evacuated and the shops relocated, though it is unclear if the shopkeepers were offered any help to do this.

Rescue workers searching the debris beneath the 19 July 2019 Ginigathhena landslide. Daily News.

The incident happened amid heavy rain associated with the Sri Lankan summer monsoon, which lasts from May to October, typically bringing around 400 mm of rain to many parts of the country in an average year. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall.


 Onlookers above the scene of the 19 July 2019 Ginigathhena landslide. The shops destroyed would formerly have stood in the foreground of this image, facing onto the visible road. Colombo Gazette.

Monsoons are tropical sea breezes triggered by heating of the land during the warmer part of the year (summer). Both the land and sea are warmed by the Sun, but the land has a lower ability to absorb heat, radiating it back so that the air above landmasses becomes significantly warmer than that over the sea, causing the air above the land to rise and drawing in water from over the sea; since this has also been warmed it carries a high evaporated water content, and brings with it heavy rainfall. In the tropical dry season the situation is reversed, as the air over the land cools more rapidly with the seasons, leading to warmer air over the sea, and thus breezes moving from the shore to the sea (where air is rising more rapidly) and a drying of the climate. 

 Diagrammatic representation of wind and rainfall patterns in a tropical monsoon climate. Geosciences/University of Arizona.
 
See also...

https://sciencythoughts.blogspot.com/2017/12/twenty-two-confirmed-deaths-as-cyclone.htmlhttps://sciencythoughts.blogspot.com/2017/09/british-tourist-killed-by-crocodile-in.html
https://sciencythoughts.blogspot.com/2017/05/flooding-and-mudslides-kill-at-least-91.htmlhttps://sciencythoughts.blogspot.com/2017/04/twenty-six-confirmed-dead-and-over.html
https://sciencythoughts.blogspot.com/2017/05/flooding-and-mudslides-kill-at-least-91.htmlhttps://sciencythoughts.blogspot.com/2014/12/at-least-six-dead-following-landslide.html
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