Mudflows are streams consisting of mud and stones that crawl along the slopes of the mountains and riverbeds, sweeping away any obstacle in its path. This natural phenomenon is one of the most life-threatening people and the infrastructure of settlements.
Mudflows
During the rapid melting of glaciers in the mountains, as well as after heavy rains, storms, hurricanes, water accumulates in front of a natural obstacle. In some places quite large lakes and reservoirs are formed. Such formations are called moraine lakes; it is they that after some time are transformed into landslides, mudflows, landslides and avalanches. Moraines consist of:
- Sand.
- Boulders.
- Ice and snow.
- Hard rocks.
- Crushed stone
- Clays
At some point, a huge mass of mud, mixed with water and stones, breaks through the dams, rushing down a rapid stream. Developing tremendous speed, emitting a loud roar, the stream is gaining more stones and trees along the road, thereby increasing its destructive power.
Mudflows at the beginning of their movement reach no more than 10 meters in height. After a natural cataclysm breaks out of the gorge and rushes from the mountain, it spreads over a flat surface. Its speed and height will decrease significantly. Having reached an obstacle, he stops.
Consequences of the descent of rocks and water
In the event that a settlement appears to be a mudflow, the consequences for its population can be catastrophic. Natural disaster is deadly, and often leads to large material losses. The gathering of rocks and water brings especially much damage to villages where people live in weakly fortified frame houses.
The consequences of landslides, mudflows and landslides are catastrophic. So, a major disaster occurred in 1921 in the former capital of Kazakhstan - Alma-Ata. Late at night, a powerful mountain stream of about a million cubic meters hit the sleeping city. As a result of the emergency, a strip of stones and mud 200 meters wide was formed right in the middle of the city. Buildings were destroyed, infrastructure was damaged, people were killed.
In Russia, mudflows are also often formed in mountainous areas, especially in those places where it rains heavily, for example, in the Caucasus and the Far East. In Tajikistan, there are villages every year in the spring season. Especially often this phenomenon occurs in high mountains during snowmelt.
Mudflow protection
In order to protect the population and tourists from sudden rock gatherings in especially dangerous mountainous regions, where landslides, mudflows, landslides and avalanches periodically occur, it is necessary to monitor them from the air. Specialists observe the formation of mountain lakes and can tell in advance about the danger of an emergency disaster. Engineers also develop anti-mudflow artificial barriers and branch channels, which reach several hundred kilometers in length.
In 1966, near the city of Alma-Ata, a protective dam was built from the ground and large cobblestones. The total weight of building materials amounted to about 2.5 million tons. After 7 years, the artificial construction saved the lives of many citizens, blocking the city from the mudflow of unprecedented power.
Despite the fact that in most cases, mudflows collapse from the mountains suddenly, scientists have learned to predict their approach according to some signs, for example, by a change in the color of water in a mountain lake.
Survival during an emergency
Tourists who often travel in the mountains should be aware of the danger of landslides, mudflows, landslides, and life safety. Safety rules can one day save your life!
To properly prepare for a difficult and lengthy trip to the mountains, you should find out the weather forecast before going out. If it rains heavily in the mountains, then the likelihood of dirt flowing off significantly increases. For safety, it is better to stay on the inside of the river bend, since the mud rises much higher on the outside. Also, do not spend the night near mountain lakes and rivers, as well as in narrow gorges.
What are landslides
A landslide is a displacement down the slope of the formed mass consisting of rocks. The cause of their occurrence most often becomes heavy rains, as a result of which rocks are washed away.
Landslides can take place at any time of the year, and differ from each other in the scale of destruction. A slight displacement of the rock will damage the roads. Significant destruction and splintering of stones leads to the destruction of houses, as well as to human casualties.
Separation of landslides into types
Landslides are divided into slow, medium and fast. The first move at an insignificant speed (several centimeters per year). Medium - a few meters per day. Such displacements do not lead to disasters, but sometimes such natural phenomena lead to the destruction of houses and outbuildings.
Rapid landslides are considered the most dangerous, because in this case, streams of water with stones break down from the mountains and move down with great speed.
All rock and clay mass movements can be predicted by looking at the following signals:
- new cracks and crevices formed in the soil;
- falling stones from the mountains.
How to avoid destruction and casualties
Against the background of incessant showers, the above signals should become harbingers of danger for the special services and the population. The timely detection of signs of an impending landslide will help to take measures to save and evacuate the population.
As a prevention and protection against destruction, protective networks, artificial tunnels are built near cities, and they also create vegetation from trees. Shore protection structures and fastening of slopes with the help of piles have also proven themselves well.
Where do they arise
Many people wonder where snow avalanches, landslides, mudflows and landslides most often occur. The displacement of rocks, huge masses of snow and water occurs in areas or slopes as a result of an imbalance caused by an increase in the steepness of the slope. This mainly happens for several reasons:
- Heavy rains.
- Weathering or waterlogging of the rock by groundwater.
- Earthquakes.
- Construction and economic activities of man, in which the geological conditions of the area are not taken into account.
The landslide is enhanced by the slope of the earth towards the cliff, cracks on the top of the mountain, which are also directed towards the slope. In places where the soil is most moistened by rain, landslides take the form of a stream. Such natural disasters cause enormous damage to agricultural land, enterprises and settlements.
In mountainous areas and the northern regions of our country, the thickness of the soil is only a few centimeters, in connection with this it is very easy to break. As an example, we can cite a place in the Eagle Sopka region (Vladivostok city), where uncontrolled deforestation began in the early 2000s. As a result of human intervention on the hill vegetation disappeared. After each downpour, a stormy stream of mud spills onto the streets of the city, which had previously been blocked by trees.
Landslides are often found in areas where slope erosion processes are actively taking place. They occur when rock masses lose support as a result of an imbalance. A massive landslide occurs in places where there are:
- slopes of the mountain, composed of alternating waterproof and aquiferous rocks;
- Man-made dumps of rocks near mines or quarries.
Landslides moving from the side of the mountain in the form of a pile of debris are called rockfalls. If a huge block of stone slides along the surface, then this natural phenomenon is called a collapse.
Large landslides
To learn more about the largest convergence of landslides, mudflows, landslides, avalanches and consequences for people, you should turn to historical literature. Witnesses of terrible disasters often describe the gathering of large masses of rock and avalanches from ancient times. Scientists believe that the largest stone gathering in the world occurred at the beginning of our era near the Saidmarrech River in southern Iran. The total mass of the landslide was approximately 50 billion tons, and its volume was 20 cubic kilometers. The mass, consisting of stones and water, collapsed from Mount Kabir-Bukh, whose height reached 900 meters. A landslide crossed a river 8 kilometers wide, then it crossed the ridge and stopped after 17 kilometers. As a result of the closure of the river, a large lake was formed with a depth of 180 meters and a width of 65 kilometers.
In ancient Russian chronicles there is information about huge landslides. The most famous of them dates back to the 15th century in the region of Nizhny Novgorod. Then 150 yards suffered, many people and farm animals suffered.
The scale of destruction and the consequences of landslides and mudflows depend on the density of buildings and the number of residents in the disaster area. The most devastating landslide occurred in Gansu province (China) in 1920. Then more than 100 thousand people died. Another powerful landslide that claimed the lives of 25 thousand people was recorded in Peru (1970). As a result of the earthquake, a pile of stones and water collapsed onto the valley at a speed of 250 kilometers per hour. During a natural disaster, the cities of Ranrahirka and Yungai were partially destroyed.
Landslide forecast
In order to predict the landslide and mudflows, scientists are constantly conducting geological research and make maps of dangerous areas.
To identify areas of accumulation of landslide material, aerial photography is carried out. The photographs clearly show the places where the most likely collapse of rock fragments. Geologists also determine the lithological features of the rock, the volume and nature of the flow of groundwater, vibration due to earthquakes, as well as the angles of slopes.
Landslide protection
If the likelihood of landslides and mudflows is high, then special services take measures to protect the population and buildings from such a natural phenomenon, namely, they strengthen the slopes of the seas and rivers with a wall or beams. The soil is prevented from slipping by staggering piles, planting trees, and also artificially freezing the earth. To prevent the descent of wet clay, it is dried by electroosmosis. The convergence of landslides and mudflows can be prevented by first building drainage structures that can block the path to underground and aboveground waters, thereby preventing erosion of the soil. Surface water can be diverted by pulling out canals, and underground water can be drilled through wells. Such measures are quite expensive to implement, but such measures can prevent the destruction of buildings and avoid human casualties.
