Volcanic eruptions, earthquakes, mudflows, landslides, landslides, avalanches, karst phenomena with sedimentation of the earth's surface - all these natural disasters are related to geological emergencies. Some of the natural disasters can be predicted, most cannot. But to study the rules of behavior in such circumstances must necessarily from childhood. This article may be useful to the teacher who compiles the lesson on life safety "geological emergencies."
Earthquake
The sudden displacements and ruptures of the earth's crust or upper mantle, resulting in tremors with vibrations of the earth's surface, transmitted over great distances as elastic vibrations, is an earthquake. Such an emergency plan of a geological nature usually occurs in three phases - fortshocks, main shock and aftershocks.
The shocks themselves and the waiting time between them are very different. The main one is characterized by the greatest strength, and in duration it is usually only a few seconds, however, people feel it as very long. Aftershocks produce an even greater mental shock: people feel the inevitability of misfortune, are constrained by fear, are inactive, but you need to defend yourself and look for safe places.
Force measurement
Where the main release of energy occurs in the volume of the Earth’s thickness, there is an earthquake source. The hypocenter, or its focus, is a conditional point in the center of the focus, and the projection of the hypocenter on the surface is the epicenter around which the greatest destruction occurs. The earth is never at rest, every year the same earthquakes are recorded by many hundreds of thousands, but for the most part they are so weak that people do not even notice them.
That is, it is not a geological emergency. Points that measure the intensity of an earthquake are awarded by the number of destructions on the surface. This is the most widely used Richter scale, as well as the International scale for measuring the strength of earthquakes. Magnitude is a characteristic of the total energy of elastic vibrations caused by this natural disaster.
Earthquakes in Russia
In our country, twenty-eight percent of the regions are quite seismic hazardous. Most often, emergencies of a geological nature occur in Kamchatka, in the Baikal region, in southern Siberia, on the Kuril Islands and in the North Caucasus. Protection against such disasters is an acute concern. Antiseismic measures are divided into two groups - preventive and implemented immediately before and during the earthquake. Preventive measures are prevention that takes place before a natural disaster threat arrives.
Scientists study the phenomena in which geological emergencies of a natural nature occur , reveal their mechanisms, identify all the harbingers of trouble, and develop forecast methods. And when the "thunder has already struck," you just need to save people - littered in their homes, left homeless. Settlements and enterprises should be built taking into account the earthquake resistance of the area - this is first of all. Otherwise, an emergency of a geological nature will bring enormous disasters, examples of the Armenian Spitak are unlikely to be forgotten soon. The population needs to be trained in the correct behavior, the level of organization of rescue operations should also be at its best. The warning system is one of the main conditions for the absence of many victims.
Eruption
Active processes constantly occur in the depths of the Earth, the result of which is active volcanic activity. Eruptions threaten those two hundred million people who live too close to dormant volcanoes. An emergency of a geological nature, examples of which we find even in antiquity (the death of Pompeii), is associated with the movement of magma in the earth's crust, that is, with volcanism. Magma - translated from Greek as "thick ointment" - is a molten silicate mass, that is, stones heated to fluidity at the highest temperature in the depths of the Earth.
If these magma masses reach the surface, as a result of tremendous pressure from within, an eruption begins, and red-hot streams of liquid stone float on the ground, destroying everything in its path. This is the so-called lava, that is, magma, from which huge quantities of various gases, often poisoning all living things, have already disappeared, and they carried away clouds of ash for many kilometers and for a long time covering the sunlight.
Volcanoes in Russia
An emergency characterization of a geological nature, such as a volcanic eruption, can be given with a full understanding of the nature of this phenomenon. After the formation of the planet and its cooling, numerous channels and cracks formed in the earth's crust, where magma comes very close to the surface. And at some point magma begins to pour out of magma chambers at a depth of about sixty kilometers, as a result of enormous pressure. This is how volcanoes form - freestanding mountains that created themselves from the products of their own eruptions.
There are three types of volcanoes: extinct, asleep and active. Asleeps are an unclear threat, because humanity does not have information about their eruptions, but local earthquakes underneath them do occur, that is, at any moment when it shakes harder, the volcano can wake up. Extinct - inactive volcanoes, they even very often lost their shape. Active are a constant source of danger due to the probability of eruption.
Yellowstone and other supervolcanoes
There are also supervolcanoes, as, for example, in American Yellowstone. There are about twenty such on Earth. They sleep for a very long time - sometimes millions of years. But when they wake up, an emergency of a natural geological nature does not occur anymore. Examples of ice ages say a lot. The last eruption occurred in New Zealand twenty-seven thousand years ago. Ashes covered the earth with a multimeter layer, in addition, covered the sun for several years. It was released into the atmosphere of approximately one thousand two hundred square kilometers.
The concentration of ash, even from an ordinary volcano, is sometimes so great that for several days it is dark, like at night. Then the night came on the whole earth and it lasted not days, but years. Plus, three billion tons of sulfur dioxide spread in the air over almost the entire earth. Sulfuric acid rains began, under which all the vegetation was dying. The earth then lost up to eighty-five percent of the species of birds only. Those who live in our days are a pitiful fifteen percent of the former splendor. And the main thing is that it’s almost impossible to fight even with an ordinary active volcano, you won’t even get away from an awakened supervolcano - there is nowhere to go. Now try to call the emergency of a geological nature worse than that.
Landslide
Landslides are found in our country everywhere in areas where there is no evenness of the landscape. Geological emergency situations are numerous and diverse, and landslides are not considered the most dangerous. Although unexpected - there are. Why does it happen that under the weight of the soil huge slopes of mountains and hills crawl down, sea, lake and river terraces slide, collapsing?
The stability of the slope is violated, since the cohesion of rocks or soil is unexpectedly less than gravity. Then the slope begins to move. This is not such a big catastrophe, in which thousands of people die, but the damage is very great: houses are destroyed, communications are buried, tunnels and pipelines no longer exist, especially electric networks and telephone cables.
What causes landslides
Factors that can cause a landslide can be different, and very often human activity is such a factor. This is waterlogging, destruction of vegetation (deforestation) or a change in the type of planting, weathering and, again, earthquakes that almost always cause landslides. There are three types - fast, medium and slow. Only with fast landslides many people die. There are still differences in the depth of the sliding surface: shallow - up to five meters, surface - up to a meter, deep - up to twenty meters and, accordingly, very deep - over twenty.
The power of the mass of rocks involved is also being graded: small landslides take up to ten thousand square meters of soil, large ones up to a million. However, not only on earth do such emergencies of natural geological nature occur. The examples are confirmed by the huge destruction from the tsunami, which most often forms as a consequence of an underwater landslide, which, in turn, occurred after the earthquake. Disruptions of sedimentary rocks at the edges of the shelves are very large. In Scotland, after a landslide in prices, it demolished everything at a distance of eighty kilometers from the coast.
Sel
Also the consequences of earthquakes, mudstone flows on rough rivers with huge kinetic energy and a speed of more than fifteen kilometers per hour. In terms of capacity, mudflows are also divided into groups: if mudflow is more than one hundred thousand cubic meters, it is a powerful mudflow, there are medium ones - up to one hundred thousand, and weak ones - less than ten thousand cubic meters.
The danger of mudflows is in their suddenness, very rapid growth and sometimes lasting more than eight hours. They can be predicted with some success by analyzing the results of observations. Special hydraulic structures are being built for mud retention and targeting. The main thing is not to cut down trees on the mountain slopes, in the absence of fixing by the root system, the risk of mudflow increases many times.
Avalanche
A snowfall, with a huge mass falling or sliding off the mountain slopes and enthralling more and more masses. In Europe, the actions of the population in case of emergencies of a geological nature are quite targeted, but even there under the avalanches more than a hundred human lives end each year. The destructive power of an avalanche is very large, because it contains a large kinetic energy. They are divided by the nature of the movement into jumping, trough and slope.
Avalanches form mainly on treeless slopes, where the steepness is more than fifteen degrees, but most often this happens at thirty or forty. If the slope is more than fifty degrees, then avalanches will not form, since the snow is falling to the foot gradually. Her speed can be prohibitive - more than a hundred meters per second. It is impossible to predict the avalanche. Accumulations of snow in dangerous places are simply shot, provoking a descent, or purposefully explode.
Collapse
Steep and steep mountain slopes are also dangerous by collapses when large masses of rocks come off and fall as a result of the loss of their integrity from weathering or under the influence of water - surface or underground, from sudden changes in temperature and other natural factors.
Collapses also provoke cyclones and storms, earthquakes and technogenic activities, even the gravitational impact of the moon. In 1995, a large collapse occurred in Ingushetia, its length is one hundred and fifty meters, its width is ten, and its depth is about fifty meters, sixteen people died there. It is also impossible to predict collapses.
Afterword
Scientific and technological progress can be blamed for the fact that it not only cannot protect people and the technosphere from emergency situations and natural disasters, but, on the contrary, it provokes them. The number of victims increases from year to year by 4.3%, while the number of victims from destructive natural phenomena becomes 8.6% more annually. Economic losses are also rising.
This problem is global. The aggravation of natural hazards comes from an increase in anthropogenic impact on the surrounding world, irrational use of economic facilities, improper resettlement of people, inadequate monitoring of the natural environment, weakening by states of monitoring systems for natural phenomena, poor state of protective engineering structures, and afforestation. Earthquake-resistant construction is required. Only then will people feel protected during a geological emergency. It is impossible to speak briefly or fluently about this problem.