Sciency Thoughts: Health and Safery

Showing posts with label Health and Safery. Show all posts

Sunday, 23 April 2023

Eight confirmed deaths following landslide on the Pakistan/Afghanistan border.

Eight people have now been confirmed dead following a landslide close to the town of Torkham on the Pakistan/Afghanistan border on Tuesday 18 April 2023. The majority of the deceased are understood to be Afghan truck drivers who were cooking beside their trucks while waiting for a border crossing to open. The landslide buried about fifteen container trucks, carrying goods from Pakistan into Afghanistan, with several people being injured as well as those killed. Initial rescue attempts are understood to have been hampered by a fire triggered by the landslide crushing a gas cylinder used for cooking, while later in the week further problems were caused by heavy rainfall and a secondary landslide.

Rescue workers searching the remains of trucks destroyed by a landslide on the Pakistan/Afghanistan border on 18 April 2023. Rescue 1122 Khyber Pakhtunkhwa.

The immediate cause of the landslide appears to have been heavy rainfall falling in the area. 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 and landslides are common at this time of year in northern Pakistan, where rising temperatures at the start of summer lead to thawing snow and ice in the mountains of the region. However the area does not typically receive large amounts of rainfall at this time of year, although such events seem to be becoming more common with the changing climate.

A huge landslide on the Torkham Export Road, close to the Torkham border crossing linking Pakistan and Afghanistan. Pakistan Armed Forces News/Twitter.

The Himalayan provinces of Pakistan are extremely prone to landslides, due to a number of active faults in the area, these being driven by the northward movement of the Indian Plate, which is pushing into Eurasia at a rate of 40 mm a year. This causes earthquakes on both plates, as well as the folding and uplift that has created the Himalayas and the Tibetan Plateau.

Block diagram showing how the impact of the Indian Plate into Eurasia is causing uplift on the Tibetan Plateau. Jayne Doucette/Woods Hole Oceanographic Institution.

However, the area around Torkham is not generally prone to large landslides, even at times of year when high rainfall is expected, suggesting that something else may have contributed to this event. Landslide expert Dave Petley has suggested on his blog that this may relate to road widening activity at the landslide site, which may have undermined a section of rock above an unconformity in the rockface, leading to a plane of weakness along which the rock could fail.

Google Earth images of the site of the Torkham landslide in 2016 and 2021. Dave Petley/The Landslide Blog.

Tuesday, 19 April 2022

Warnings issued to bathers after Compass Jellyfish spotted in the Dardanelles Strait.

Authorities in western Turkey have issued a warning to bathers after Compass Jellyfish, Chrysaora sp. (probably Chrysaora hysoscella), were spotted in the Dardanelles Strait close to the port of Çanakkale. The Jellyfish, which can deliver a sting comparable to that of a Bee, are not normally seen in the Dardanelles Strait, and people there may be unfamiliar with them. While individually the stings of these Jellyfish are comparatively mild, their tentacles can grow to a meter and a half in length, which often stick to their victims delivering multiple stings, and the stings will remain active when the Jellyfish have died, or the tentacles have become detached. If people are stung by these Jellyfish the recommendation is that the sting is treated with vinegar as quickly as possible - and not fresh water, which will make the sting worse.

A Compass Jellyfish, Chrysaora hysoscella, at the Acquario di Genova in Italy. Francesco Crippa/Flickr/Wikimedia Commons.

Compass Jellyfish are native to the southern Mediterranean, but rising temperatures associated with global warming, combined with increased nutrient runoff, have enabled to spread northwards in the summer months, through the Dardanelles Strait into the Sea of Marmara and the Black Sea. There are concerns that a further temperature rises could lead to permanent populations becoming established in these areas, changing the ecology of these regions and damaging fisheries in the area.

A Compass Jellyfish, Chrysaora sp., on a beach near Çanakkale in western Turkey on Monday 18 April 2022. DHA Photo.

Jellyfish, although often large, are entirely planktonic in nature, meaning that they simply drift in the water column, and are unable to swim against currents, so that storms or other events that cause temporary changes in current flow can deposit large numbers on shorelines. Jellyfish numbers are determined largely by nutrient availability, as nutrient levels determine the amount of phytoplankton (single-celled Algae) in the water column, and this in turn controls the numbers of smaller zooplankton (small planktonic Animals), which are the main source of food for Jellyfish.

Tuesday, 21 December 2021

Russian mine safely evacuates 128 employees after a rise in carbon monoxide is detected.

A mine in Kemerovo Oblast in southwest Siberia has safely evacuated 128 miners who were working below ground when a rise in carbon monoxide was detected on Sunday 19 December 2021. The sudden increase triggered concerns that a fire might be burning within the mine (coal, which is essentially pure carbon, usually burns to produce carbon dioxide, but when the oxygen supply is limited, as in an underground mine, incomplete combustion can result in the production of the more deadly carbon monoxide). However, the owners of the Ruban Mine have found no evidence of a fire, and now believe the gas was emitted directly from the coal following a rise in temperature within the mine.

Russian emergency workers attending a mine in Kemerovo Oblast following the detection of a rise in carbon monoxide levels, which provoked concerns about the risks of an underground fire. Generico.

Coal is formed when buried organic material, principally wood, in heated and pressurized, forcing off hydrogen and oxygen (i.e. water) and leaving more-or-less pure carbon. Methane is formed by the decay of organic material within the coal. There is typically little pore-space within coal, but the methane can be trapped in a liquid form under pressure. Some countries have started to extract this gas as a fuel in its own right. When this pressure is released suddenly, as by mining activity, then the methane turns back to a gas, expanding rapidly causing, an explosion. This is a bit like the pressure being released on a carbonated drink; the term 'explosion' does not necessarily imply fire in this context, although as methane is flammable this is quite likely.

Coal is also comprised more or less of pure carbon, and therefore reacts freely with oxygen (particularly when in dust form), to create carbon dioxide and (more-deadly) carbon monoxide, while at the same time depleting the supply of oxygen. This means that subterranean coal mines need good ventilation systems, and that fatalities can occur if these break down.

While this incident resulted in no harm, with employees being safely evacuated from a potential threat, which is good practice in mine safety management, the Russian Emergencies Ministry has raised concerns about mine safety in Kemerovo Oblast, following an explosion at the Listvyazhnaya Mine which killed 51 people in November, with one of the mine's owners subsequently being arrested on suspicion of falsifying data on methane emissions within the mine. Kemerovo Oblast was also the location of the worst mining disaster in post-Soviet Russian history, when an explosion at the Ulyanovskaya Mine killed more than 100 people.