The fire has been burning for 6,000 years, and it has not been extinguished yet. The ground is cracked, but there is only smoke on the surface!
Forest fires can be divided into three types: surface fires, canopy fires and underground fires. Surface fires have the highest incidence, and most forest fires are surface fires. Generally, this kind of fire covers a large area, and causes great damage and loss to the forest, and the canopy fire is the most difficult to extinguish. The above two kinds of fires can see open flames and are easy to find, but it is difficult to find underground fires.
underground fire
Underground fires, also known as peat fires or humus bed fires , are slow-burning, slow-moving, and modest fires beneath the soil. Generally 4-5 meters per hour , it is difficult to find flames on the surface, only smoke. Underground fires are difficult to extinguish and last for a long time, sometimes for several years or even hundreds of years . Fortunately, underground fires are relatively infrequent, accounting for about 1 percent of forest fires.
Why is there a fire underground?
We know that one of the ways to deal with a fire is to cover it with sand, in this case the ground is full of soil, how can it still catch fire?
The underground is not just as simple as soil, there are also many animal remains and plant decay that generate combustible gases , which are deposited in the soil for a long time to form a humus layer or peat layer. Whether it is humus layer, peat layer, coal seam or oil and gas layer, they all contain a lot of carbon and can be burned, but the temperature below the surface is not high enough to reach the ignition point; in addition, the underground soil is difficult to contact with the air, so underground fires rarely happen combustion.
1. Soil loosening
However, the soil is not airtight, it has many small cracks through which the subterranean humus layer can come into contact with the air. In addition, the activities of animals will also loosen the soil, such as: wild boar arches, earthworm activities . Other animals burrow beneath the soil, helping the humus layer come into contact with the air.
2. Sporadic fire source
Humus does not start underground fires when it comes into contact with the air, but it can start surface fires if there is a wildfire in the local forest , or if people bring the fire into the forest . After the surface fire is extinguished, sporadic fire sources may cause underground humus fires. Underground fires are usually in the form of smoldering , because it is difficult to form flames underground, and most of them burn in the form of sparks. During the smoldering process of underground fires, the moisture in the surrounding soil will be dried, causing underground fires to continue to spread.
Underground Fire Hazards
Underground fires have insufficient contact with oxygen, resulting in incomplete combustion , which produces a large amount of carbon dioxide and seriously pollutes the air . Secondly, the underground fire burns underground, and it is difficult to see anything abnormal on the ground. Although there is no abnormality on the ground, the ground has been burned hollow, like an empty shell. Once people or animals pass by, the ground will collapse . , causing irreparable damage.
After the collapse, more cracks will be produced, which will increase the contact area between the underground fire and oxygen, and make the scope of the underground fire larger. After the underground fire reaches the roots of the tree, it will slowly burn through the tree. After burning, trees increase the contact area with oxygen. At this time, the ground will form a fire, and the fire is very violent.
A fire that has been burning for 6,000 years
In South Wales, Australia , a fire has been burning for more than 6,000 years and has not been extinguished, so the mountain is also known as the "burning mountain" .
The reason why this mountain can last for 6,000 years is that the underground fire is not strong and the burning speed is slow; on the other hand, it is a coal mine with more underground fuel, which can support burning all year round. Due to the large burning area and wide burning range of the mountain , and the fire is located underground, it is difficult to see with the naked eye, so it is difficult to extinguish the fire.
During the smoldering process of underground fires, due to insufficient combustion, it is easy to form a large amount of carbon monoxide, which is harmful to people and animals, so it is difficult for local residents to survive here. However, it has been turned into a tourist area, where tourists can come to watch the underground fire burn.
Conclusion : Due to the difficulty of extinguishing underground fires and the huge damage to the environment, local ecology, and economy, countries all over the world are working hard to solve the problem of underground fires , but there is no better way now.