Formation of sinkholes. What is Karst Provo

2024 Author: Henry Conors | [email protected]. Last modified: 2024-02-12 02:44

Our planet is like a huge gift bag: no matter how you dig in it, you can always find something new. The Earth constantly presents researchers with surprises, and this has been happening for a very long time. A perfect example is the phenomenon of sinkholes that form regularly around the world.

Cheese with holes, or about the precariousness of being…

Man has known about the existence of massive underground voids since time immemorial. It is quite natural that in ancient times they were associated exclusively with the machinations of evil spirits, people in every way avoided those places where their regular education took place. Holes from karst sinkholes were considered gates to the underworld.

Centuries passed, man mastered various sciences. Gradually, geologists revealed the secret of these natural formations. So. Underground voids are formed in those places where the rocks lying in the depths of the earth are highly susceptible to water erosion. When water seeps through the soil layer, it gradually erodes the same limestone, resulting in an underground cavity. Ofteneven majestic karst lakes are formed in the depths of the earth, which for centuries remain unattainable for humans.

You probably know at least one of the world-famous underground caves with stalactites and stalagmites: no matter how strange it may sound, but these are all the same caste voids. In some areas of the earth, the layer of rock under the soil in terms of the number of holes can successfully compete even with Swiss cheese. Since the collapse of the soil layer constantly occurs in these parts, a rather peculiar landscape of the area is formed, which is called the "karst relief".

For a long time people treated such places with the greatest reverence, as they considered them the abode of Gods and spirits. In principle, they can be understood: when looking at other landforms, landscapes of distant planets immediately come to mind…

What is karst scientifically

By the way, do you know where the term “Karst” came from? And this definition went from the name of the area in northern Italy, Krasa (Karsta). Similar natural phenomena are observed in many places in Slovenia and Croatia.

From a scientific point of view, this is a set of geological processes and phenomena. You should know that the occurrence of sinkholes is possible only in areas where the corresponding types of rocks occur (which we have already mentioned above).

Important! Professional geologists often distinguish pseudokarst. This term refers to the formation of voids in the soil and underlying rocks. The difference from the "true" karst is thatthat they were formed as a result of natural processes other than dissolution. For example, caves that arise after mudflows or the passage of a lava flow fall under this definition. Do not forget also about the voids that appear as a result of human activity (gas and oil production).

We will now tell about such phenomena. The most famous is one "Latin American" sinkhole. Guatemala is the city where she appeared.

Latin America

It was the last day of May 2010 outside. Across Central America, tropical storm Agatha rushed at full speed, destroying everything in its path along the way. In the morning, everything was quiet, and in the capital of Guatemala, utilities began to engage in restoration work. Suddenly, a huge funnel formed at a busy intersection, the diameter of which was 18 meters, and the depth reached 60 meters. A three-story residential building and a one-story outbuilding instantly fell into a huge karst sinkhole.

Oddly enough, but for Guatemala this event was not something from the category of incredible: just three years before, just a few kilometers from the city, a sinkhole was also formed, the depth of which was one hundred meters. Unfortunately, in both cases, there were human casu alties.

What was it

Immediately after the incident, everyone assumed that everything happened as a result of the formation of sinkholes. But geologists quickly figured out that the city stands on dense volcanic pumice, which simply cannot physicallybe blurred. How did it happen that a giant cavity formed in a layer of dense geological rock?

Oddly enough, but negligent public utilities were to blame for everything. Due to the constant accidents and breakthroughs of sewer pipes that were laid in ancient times, a real underground network of foul-smelling sewage rivers formed under the city. Their "waters" eroded and dissolved the pumice, which soon began to wash away at a staggering rate. As a result, a huge cavity gradually formed in the thickness of the soil.

Rain is not always good…

In May 2010, the situation was further aggravated due to the huge amount of rainwater brought by Agata. Subsequently, the researchers found that in some places "karst" lakes were formed, which are still filled with a mixture of rainwater and sewage. Needless to say, how badly such "seas" affect the epidemiological situation throughout the city.

Thus, the case we have described is not a sinkhole. Guatemala is one of those few areas on Earth where their formation is in principle excluded. In general, earth sinkholes are often observed all over the world. Often their dimensions are really impressive: the diameter of the funnel can reach several tens of meters, not to mention a depth of a couple of hundred meters.

Because of what the frequency of their formation is growing

Despite education, in many regions these natural phenomena continue to be considered something supernatural to this day. And people can understandit seems incredible that a solid and stable firmament under one's feet can turn into a grandiose failure in a couple of seconds, in which even houses of several floors disappear. The situation is getting worse every year, and therefore people's anxiety is growing.

Experts say that the fault of almost every second karst failure lies with the person himself. The fact is that people overload the surface of the earth with giant buildings, and also have an extremely negative impact on the balance of groundwater. Due to human activity, their level is constantly decreasing, and therefore the risk of failures increases significantly.

Anthropogenic factor

The clearest example of the fact that even a huge karst basin can be caused by a person is West Florida, USA. You will laugh, but in the same 2010, a sinkhole of impressive size appeared at the local landfill. Local geologists almost turned gray, because according to the conclusions of experts (dated in 1980), this area was absolutely stable (which is why it was chosen for a dump).

Everything was explained simply: just under that place was the bed of an underground river. Since that year was a dry one, water from it was intensively pumped out throughout the state. The result is failure.

In America alone, the annual damage caused by failures is estimated at 10-15 billion (!) Dollars.

Oddly enough, but sometimes karst landforms can serve a person well. The fact is that such places are usually extremely beautiful. perfect examplecan serve as numerous sinkholes in the forests of Indonesia, as well as the majestic Great Blue Hole, which is located off the coast of Belize.

Irrational use of groundwater

In many ways, the root of all evil lies in the fact that humanity is extremely irrationally using the most valuable resource of soil and groundwater. Of course, it is difficult to get away from this: moisture is the most valuable resource, and with the development of world agriculture, it is used in increasing volumes. Groundwater is pumped out everywhere to irrigate agricultural land, and somewhere to this day they use the disastrous practice of draining swamps, which leads to increasingly unfavorable consequences. So, in many countries there is already a shortage of drinking water.

Until recently, only science fiction writers wrote about the coming wars for her, and today quite "mundane", pragmatic specialists are talking about the same.

German Misadventures

We emphasize once again that karst voids are quite natural phenomena. In the same 2010 (it was a turbulent time), the quiet and calm German town of Schmalkalden in Thuringia twice discussed an incredible event. On a quiet November morning (November 1), right in the middle of the main street, a huge crater with a diameter of 40 meters was formed, the depth of which immediately reached 20 meters. As soon as passions subsided, the same thing happened on November 11 in the same place.

Directly on the border with the old crater, a new one has formed, taking several garages of local residents with it. Soas the ground collapsed at night, no human casu alties were avoided.

Hell Gate

Relatively recently, it became known that in the crevices of hills, which are located in the Turkmen desert of Karakum, there is a considerable amount of natural gases. More precisely, it was possible to find out about this only in 1971. At that time, near the small village of Darvaz, drillers were making another well. During this fascinating process, they got straight into the karst underground cavity with a drill. It had gas in it. A lot.

The drilling rig almost immediately collapsed into the resulting cavern, the diameter of which was 20 meters, and the depth - all 60 meters. Fortunately, there were no casu alties, but gas began to come out of the ground. Since its composition posed a danger to the lives of people and animals, they decided to set it on fire. Experts assumed that gas reserves would soon burn out. Alas, they have been burning for more than four decades.

Since the word "Darvaz" means "gates" in the local dialect, the local population dubbed the surreal landscape "the gates of hell" as expected.

Not every failure is a karst

It is not surprising that in recent years there has been intensive research into the preventive detection of dangerous underground cavities. For example, the well-known Israeli geologist Lev Eppelbaum from the University of Tel Aviv is busy studying the sinkholes around the Dead Sea, with the help of his colleagues from Jordan and France. It must be said that this sea is a truly unique natural object. And it's not just the amazing salinity of itwaters, and also in the fact that this reservoir is located 415 meters below sea level.

Its salinity is extremely high for the simple reason that water evaporates very intensively from the surface of the sea, the sufficient volume of which the Jordan River simply does not have time to bring. In addition, the channel of the latter is becoming shallower every year, as the needs of Israel and Jordan's agriculture are growing. Accordingly, the level of the Dead Sea is also decreasing (by approximately one meter per year). So how does all this relate to the topic of the article?

S alt dips

It's simple: along the entire coast of the Dead Sea, at a depth of 25 to 50 meters, huge deposits of s alt are hidden. Previously, these places were under a layer of s alt water, but now it has receded. As a result, fresh ground water begins to come into contact with the s alt lumps. As a result - a kind of "karst" areas, densely dotted with failures. As you might guess, the latter arise due to the erosion of s alt with water.

Today, the number of caverns, the diameter of which varies from a meter to 30 meters, is estimated at several thousand. From the air, the region is increasingly beginning to resemble the surface of the moon. And the situation is getting worse: in the eight decades during which people have observed the level of the Dead Sea, it has decreased by 20 meters.

How can I fix the situation

The situation can be saved only by increased inflow of water from the Jordan River. Unfortunately, one can only dream of such a thing, since intensively developing agriculture needs more and morevolumes. Experts talk about the possibility of digging a channel from the Red Sea. This possibility has been talked about for a long time, so there is a possibility that it will someday be made. In the meantime, geologists are testing new methods and tests that allow coastal residents to be warned in advance about the danger of a sharp subsidence of the soil.

Thus, not every failure in the ground has a karst origin. However, regardless of their origin, each of these pits is potentially dangerous due to the possibility of its subsequent sharp growth.