What is a sinkhole? How do sinkholes form and what causes them?

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The huge sinkhole with a diameter of an astounding 25 meters has “remained stable”.

A huge sinkhole has opened up in Chile and authorities have launched an investigation.

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The huge sinkhole, 25 meters in diameter and 200 meters deep, opened near a copper mine in Tierra Amarilla, 413 miles from the capital Santiago.

The National Service for Geology and Mining, Sernageomin, has dispatched specialists to the area to investigate the cause.

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The well is located on land used for copper mining by the Canadian company Lundin Mining.

Sinkholes can often form without warning, surprising people and having devastating consequences.

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So what are sinkholes, how are they formed and why? Here’s everything you need to know.

Aerial photo taken on August 1, 2022 shows a large sinkhole that emerged near the mining town of Tierra Amarilla, Copiapo province, in Chile’s Atacama Desert over the weekend. (Image: AFP via Getty Images)

What is a sinkhole?

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A sinkhole is a hole in the ground that suddenly opens up.

Often caused by erosion or water runoff, they can vary in size, being just a few feet wide or large enough to swallow cars or entire buildings.

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Sinkholes can occur naturally, but they can also be triggered by human activities such as construction, excessive extraction of groundwater, or broken water pipes.

There are two types of sinkholes, those that develop slowly over time and are known as cap subsidence, and those that occur suddenly and are known as cap collapse.

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Cover collapse sinkholes often come with little warning.

There have been instances where people have lost their homes, vehicles and even their lives in a split second.

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How are sinkholes formed?

Sinkholes form in areas where water can erode the surface rock.

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The surface rock, which is usually limestone, is easily broken down by water, which erodes it and wears away over time.

Rainwater then often fills the holes and creates an unstable surface over them, eventually causing the rock to erode and fracture, either in one rapid motion or slowly over time, forming the sinkhole.

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Heavy rain is often a trigger for sinkholes.

In New York, a sinkhole formed after severe flooding in the Bronx.

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The hole opened up in the middle of a pedestrian street and swallowed a van.

In another recent incident in Israel, a man was killed after a hole in the ground opened in a swimming pool.

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What happened in Chile?

A huge sinkhole has appeared in Chile, to which authorities have dispatched a team of specialized geologists to investigate the cause.

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The sinkhole, which is 25 meters wide and 200 meters deep, opened near a copper mine in Tierra Amarilla, 413 miles from the capital, Santiago.

The huge sinkhole in Chile measures 25 meters in diameter and 200 meters deep (Image: AFP via Getty Images)

The National Service for Geology and Mines, Sernageomin, learned of the sinkhole on Saturday (July 31).

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Agency manager David Montenegro confirmed that specialists were on site.

Montenegro said: “There is a considerable distance, about 200 meters (656 feet), to the bottom.

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“We didn’t detect any material down there, but we did see the presence of a lot of water.”

The land on which the sinkhole formed is owned by Canadian mining company Lundin Mining.

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In a statement, they said the incident did not affect workers or the local community and had “remained stable”.

They added: “Following discovery, the area was immediately isolated and the relevant regulators notified. There was no impact on personnel, equipment or infrastructure.

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“The nearest house is more than 600 m (1,969 feet) away, while any populated area or public facility is nearly a kilometer from the affected zone.”

The cause of the huge sinkhole is still under investigation.

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