Cumbrian farmer injured after falling into sinkhole.

A 70-year-old farmer from Stank in southern Cumbria, England, has been treated for chest injuries after falling into a sinkhole on the morning of Thursday 4 March 2021. The farmer was crossing a field on his property on a quad bike when the sinkhole, described as 2 m across and 18 m deep opened up beneath him. He was pulled out by rescue workers from the Cumbria Fire and Rescue Service and Duddon and Furness Mountain Rescue Team, and airlifted to hospital for treatment, although his injuries are not thought to be serious.

 

Rescue workers prepare to descend into a sinkhole that swallowed a farmer in south Cumbria, England, on 4 March 2021. Cumbria Fire and Rescue Service.

Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace.

In this case the sinkhole is thought to be associated with a disused nineteenth century iron-ore mine, many of which are found in the area. The bottom of the sinkhole was found to open out into a tunnel which extended 10 m in one direction and 4 m in the other, which is thought to be part of an undocumented mineworking.

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Houses collapse into sinkhole in Manchester, England.

Two houses have been partially destroyed by a sinkhole in Manchester, England, and it is thought the situation will get worse before it is brought under control. The situation began on the evening of Wednesday 20 January 2021, when a three metre wide sinkhole appeared suddenly outside the houses, in the Abbey Hey area of the city, swallowing a parked car, and prompting local emergency services to evacuate the four houses closest to the hole. The frontages of two of the houses collapsed into the hole later that evening, and there is concern that the remainder of the buildings is sagging and likely to also collapse.

 

Damage to houses caused by a sinkhole in the Abbey Hey area of Manchester, England, on 20 January 2021. Sean Hansford/Manchester Evening News.

Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace.

 

 

Emergency services attending the scene of a sinkhole in the Abbey Hey area of Manchester, England. Greater Manchester Fire and Rescue Service.

 

The cause of this particular sinkhole is still unclear. United Utilities initially described the hole as having been caused by a collapsed sewer, but has now changed statement, and is describing the cause as being under investigation. Manchester has suffered an increasing number of sinkholes in recent years, despite being built largely on sand and sandstone, silicate rocks which are not prone to dissolution. Domenico Lombardi of the University of Manchester has attributed these problems to the city's aging sewer system, combined with the presence of some former mined in the city, a rising population (which means more water consumption and wastewater generation), and a increasing rainfall in the area over the past decade. Where water and sewage pipes passing through soft sandstone or unconsolidated sands begin to leak, they can generate sinkholes very quickly as large amounts of water suddenly start flowing in directions not causes by natural drainage.

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Kentucky man dies after tractor falls into sinkhole.

An as-yet-unnamed 68-year-old Kentcky farmer has died after his tractor was swallowed by a sinkhole while he was working in a field, according to the Nelson County Sheriff’s Office. Officers from the Sheriff's Office were called to the farm in the Botland area, slightly before 9.50 pm local time on Monday 25 May 2020, and found that the tractor driver had been ejected from the cab of the vehicle during the fall, and died as a result.

The approximate location of the Botland Sinkhole. Google Maps.

Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace. Potash, a potassium salt, is readily soluble and can be dissolved quickly if water gains access to deposits, leading to the rapid formation of sinkholes.

Many areas of Kentucky are prone to sinkholes, as much of the state lies on karst (limestone), which is both soft and porous, allowing water to sink into it, permeating through the rock and excavating caves through which the water flows. If these caves come to close to the surface, then the ground above can collapse into the cave, creating a sinkhole at the surface.

Generalised diagram of the Inner Bluegrass Karst of Kentucky. James Currens/Kentucky Geological Survey.

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Families evacuated after sinkhole opens near homes in Black Hawk, South Dakota.

Twelve families have been evacuated from homes in the Black Hawk area of Rapid City in Meade County, South Dakota, following the appearance of a sinkhole on Monday 27 April 2020. Since first appearing the hole has expanded to cover an area of about fifteen metres by twelve, as well as breaking water and sewer lines in the area, and there are concerns that if could expand further and present a structural threat to buildings in the area.

Sinkhole in the Black Hawk area of Rapid City, South Dakota. Associated Press.

Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace.

On this occasion exploration of the hole by expert cavers revealed that it was caused by the collapse of part of an old and abandoned gypsum mine beneath the area. The mine is between seven and ten metres below the ground, and extends for over 180 m horizontally, with around 700 m of accessible passages, as much as twelve metres wide and four metres high. The mine is believed to have been excavated in the early 1900s, and used as a dump in the later twentieth century, with a variety of abandoned materials including a 1951 Ford motorcar found within the site. It is unclear if the developers that built houses above the site were aware of the presence of the mine.

A car found in an abandoned gypsum mine beneath Black Hawk, South Dakota. Dan Austin/Paha Sapa Grotto.

Gypsum is an evaporate rock, a form of calcium sulphate deposited as mineral-rich water evaporates, often around sulphurous hot springs or volcanic systems. It is a very soft rock, and soluble in water, so moisture entering gypsum deposits can cause major collapses and subsidence.

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Sinkhole in Qinghai Province, China, swallows bus and kills at least six people.

At least six people have died after a sinkhole opened up on a busy road in the city of Xining in Qinghai Province, China, on Monday 13 January 2020. The sinkhole appeared at about 5.30 pm local time, beneath a bus that was pulling up at a stop by a health clinic, swallowing the vehicle and nearby pedestrians. Several more people were swallowed while trying to rescue those already trapped as the hole continued to grow, and a breaking power line within the hole is reported to have caused an explosion and fire. As well as the six dead a further four people are missing, and sixteen more were injured.

Rescue workers at the scene of a sinkhole that swallowed a bus and several pedestrians in Qinghai Province, China, on Monday 13 January 2020. STR/AFP/Getty Images.

Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace.

 Typical sinkhole formation processes. Southwest Florida Water Management District.

On this occassion the cause of the sinkhole is still being investigated, though concerns have been raised about the rising number of sinkholes appearing in China's fast growing cities, with some people seeing a link between these events and lax building standards in rapidly developing areas.

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Hawai'ian man dies after falling into sinkhole.

A Hawai'ian man has been found dead after apparently falling into a sinkhole on his property. Police were called to the home of 71-year-old Robert Hisashi Nishimoto of Hilo on Big Island, on Monday 4 November 2019, after neighbours failed to see him for several days. a search of the property revealed a hole approximately 60 cm wide and eight metres deep, into which Mr Nishimoto had apparently fallen while trimming branches in his garden.

The approximate location of the Hilo sinkhole. Google Maps.

Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace.

On this occasion the sinkhole is believed to have been caused by the collapse of the roof of a lava tube beneath the surface. A lava tube is a form of cave formed not by erosion, as in the case of most limestone caves, but by the way in which the lava from which the rock is formed cools and solidifies. As lava flows on the surface its outermost layers, which are in contact with the atmosphere, cool and harden more rapidly than layers lower down. This means that a solid crust can form over the lava flow, slowly solidifying from the outside, while the lave beneath is still flowing. Eventually a cavern is formed through which lava is flowing surrounded by solid rock. If the supply of lava is then cut off (by an eruption ending or the lava finding a different course) before the route through which the lava is draining is blocked, then a void (cave) will be left running through the rock, which we call a lava tube.

The formation of a lava tube. Caves of Lanzarote.

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Condominium complex evacuated after sinkhole opens up beneath it in Seminole County, Florida.

A condominium complex has been evacuated after a sinkhole opened up partially undermining the structure on Tuesday 29 October 2019. The hole appeared beneath part of the Royal Arms Condominium building in Altamonte Springs, resulting in sixteen people being forced to vacate the building, the oldest of whom is described as being 92-years-old. The hole is thought to be between six and ten metres deep, although it is partially filled with water, making exact estimates difficult without approaching the hole closely. The evacuated residents are being assisted with finding alternative accommodation by the American Red Cross.

Sinkhole partially undermining a condominium building in Altamonte Springs, Florida. Jerry Hume/Spectrum News 13/Twitter.

Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace.

Many parts of Florida are particularly prone to sinkholes, due to the porous limestone that underlies much of the central part of the state. This is eroded over time by acid in rainwater (most rainwater is slightly acidic, though pollution can make this worse), and can collapse suddenly, causing overlying sediments to collapse into the hole and a sinkhole to open up. This can be triggered by human activity, such as pumping water out (which causes the water to flow, facilitating acid dissolution of the limestone), but is essentially a natural process. 

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