First, he swallowed a car. A few hours later, two terraced buildings. At 9pm on January 20, a 4 square meter crack appeared in Walmer Street, Manchester.
Another sinkhole surprised local Scottish walkers, swallowing a stretch of coastal path between Dysart and West Wemyss on February 4. And, in early March, a sinkhole opened in Cumbria under a farmer who was riding a quad bike. He was rescued by firefighters and taken to hospital.
These are just recent examples from the UK. The ground that opens up and surrounds anything that is a path is very common. Globally, for every 0.1 ℃ rise in temperature, the number of sinks increases by 1-3 percent.
A particularly large sinkhole opened in Naples at 6.30am on January 8. The 20-meter-deep, 50-meter-wide hole suddenly appeared in the Ospedale del Mare Hospital car park. It swallowed a long stretch of the car park, caused a power outage and stopped closing a facility for coronavirus patients.
Aerial photographs capture a sinkhole that opened in a hospital parking lot in Naples, Italy, forcing a residence to recover COVID-19 patients for temporary closure.
Firefighters said no one appeared to be injured, but three cars crashed. Https://t.co/4pjpSI85ag pic.twitter.com/mqU8XRM4TT
– ABC News (@ABC) January 8, 2021
Water holes are particularly common in Naples. More than 190 have opened in the city between 1915 and 2010, and there are about two to four major events each year.
A recent study of the historic canter of Naples has identified nine historic churches that are nearby and a further 57 in danger of falling to the ground.
Zinc is nothing new or even a surprise. They occur naturally when minerals below the earth’s surface gradually dissolve in water vapor to form caves. A sinkhole suddenly appears when water loosens the soils around and above caves just enough for the ground above to fall into place.
But these dreadful shortcomings are made far more common by the inclusion of human history on earth.
The growth in erratic construction, deep mining, poorly managed burial and demolition waste and, crucially, climate changes that have resulted in heavier waterfalls have caused the recent dramatic increase in the number of sinks.
Most people don’t think much about the earth. This is perhaps not surprising – there is not much to see.
Our relationship with him is usually one-way and one-sided: we aim to “improve” or take advantage of it to deliver any action service we seek – turning it into a foundation strong for buildings, or used as a source of mineral or water.
But of course the earth is a complex and delicate system, a mixture of many components – rock, minerals, bacteria, plants – that work and live independently, but which interacts continuously with together to form the hard surface and the soil on which we live and take it seriously.
Disturbance of these natural components and their harmony will allow natural hazards such as holes to sink.
Naples sink
Let ‘s use the Naples borehole to study how this happens in practice.
Ospedale del Mare Hospital sits on a rock called “phonolitic tephrite”. The term tephrite comes from the Greek tephra, meaning ashes. This is a porous and brittle rock with a bright yellow-gray color.
This rock was first used by Roman builders as a building stone. Hundreds of quarries have led to the creation of a complex network of caves beneath Naples, such as can be seen in the stone façade of Sarno Baths in Pompeii. The caves are covered in sandy ash and a high layer of urban soil mixed with construction debris and debris.
The high soil is rich in calcium and naturally interacts with carbon dioxide from the atmosphere to produce highly soluble carbonates. This upland soil was hit in three days of storms in December 2020.
It took five days before the flood water poured into the ground through historic access beams, washing away the soluble carbonates, draining the cairn and entering the sinkhole.
Consistently, natural soil is engineered into ground for buildings and roads by compaction and distillation (injecting chemicals such as cement into the soil). Natural pores in soil are either destroyed or filled with chemicals.
For soil, fewer pores means better strength, but it also means getting larger amounts of water into the ground through fewer narrower openings. This high-intensity saw can wash away soluble minerals, spread the soil around buried caves, and irrigate sinkholes.
So how do we stop this from happening?
New work
Over the past two decades, researchers have been trying to establish new ways to engineer the earth that will meet the demands of cities but not disrupt the natural systems of the earth.
For example, researchers at the University of Strathclyde have used fungi to form complex natural root-like networks in soil to hold it together. These are threads that can even recover against damage.
And, in Newcastle upon Tyne, researchers are genetically inventing bacteria to make soil a “changing living material”, so that it strengthens itself in response to loads.
But the “results” of these methods can crush the natural gaps in soil. We have not yet established the effectiveness of these methods in deeper soils, particularly in urban soils, which are mixed with construction waste.
My research team explores ways to strengthen natural gaps in urban soils, from surface to depth, in three engineered layers: bark, subsurface and subsurface.
We invent natural bacteria in the bark to release a glue-like gel and bind ground grains together. Below, the upland is designed to be lightweight, vibrant and breathable, rich in organic fiber that weaves earth grains together.
We engineer these organic fibers to allow them to stretch far further before they form a disturbance during ground movements. The subterranean in urban areas is usually rich in construction waste. We develop ways to feed these wastes on the carbon dioxide in soil and transform them into strong fibers.
Many engineers have come to look at how humans treat the earth as infertile, destructive and as far back as our treatment of endangered species, delicate ecosystems and the climate itself. . We need to employ the natural engineering skills of the age of the earth itself to build a more sustainable world. 
Arya Assadi Langroudi, Senior Lecturer in Geotechnical Engineering, University of East London.
This article is republished from The Conversation under a Creative Commons license. Read the original article.