Technological map of a geography lesson on the topic “Earthquake”

• Reports and messages
• Geography
• Earthquake

An earthquake is a movement that occurs inside our planet. These movements are associated either with the activity of volcanoes or due to the movement of lithospheric plates. The center itself is located very deep in the ground. This depth can reach hundreds of kilometers. If the cent is very deep, we will practically not feel the vibrations, but when at a depth of only 30 -45 km, this will awaken earthquakes of extraordinary destructive power. The epicenter is the place that is closest to the surface of the planet. This is where the greatest manifestations of the earthquake will occur. Scientists who study the movement of the earth's crust are called seismologists, and the branch of science itself is seismology.

Earthquakes are divided into several types:

Tectonic

These are particularly intense and extensive earthquakes; they cover large areas of the earth's surface. With such an earthquake, a shift occurs in the thickness of the earth's crust. A person practically does not feel these oscillations. But sometimes, for certain reasons, a breakthrough occurs in the layers of the crust. Then the earthquake will occur.

Volcanic

These earthquakes occur near volcanoes when they erupt. They are felt very well in nearby territory.

Landslide

These earthquakes occur due to the dissolution of rocks by groundwater. Rocks such as salts and limestones are washed away by water, this leads to voids, the soil cannot stand it and collapse occurs. At the same time, waves diverge from the fall of the earth's surface. These fluctuations are very insignificant and they are almost not noticeable.

There are several classifications based on the power of destruction. All of them are distributed according to points. One of the scales was introduced by the German seismologist Richter.

It has 10 points.

1) 1 point is felt only with special devices; a person cannot feel it on himself. 2) 2 points more than the previous one is 10 times more intense, but you can’t feel it either 3) 3 points are 10 times more intense than 2 points. It can be felt, but it does not cause much damage 4) 5 points - powerful tremors, they cause destruction in buildings. 5) 6 points - 10 times more powerful than a 5 point, can cause minor damage 6) 8.5 and more - the most dangerous earthquakes, destruction with large casualties.

Earthquakes most often occur in places where there are young mountains. There are almost no earthquakes on the plains. Earthquakes are very dangerous because they can cause serious destruction, as a result of which people can die. There is also destruction of roads and buildings.

During an earthquake, you must adhere to certain rules:

1. Do not fuss or panic 2. You must leave the building you are in 3. In a multi-story building, you can hide in the doorway 4. Do not use the elevator 5. Leave the house only between jolts

Abstract on the topic “Earthquakes, their causes and parameters”

Abstract on the topic “Earthquakes, their causes and parameters”

Content:

Introduction

1. Types of earthquakes
2. Measuring the strength of earthquakes
3. Ecological consequences of earthquakes
4. Phenomena accompanying an earthquake
5. Geography of earthquakes
6. Earthquake forecast and its types
7. Harbingers of earthquakes

Conclusion

List of sources used

An earthquake is a tremors and vibration of the earth's surface that occurs as a result of sudden displacements and ruptures in the earth's crust or upper mantle. Such tremors and vibrations of the earth's surface are transmitted over long distances in the form of vibrations. The intensity of earthquakes is estimated in seismic scores. Classical energy classification of earthquakes by magnitude (Richter scale).

Every year, about one million earthquakes occur throughout planet Earth. Most of them are so minor that they go unnoticed. Really strong earthquakes that can cause severe destruction occur on Earth about once every two weeks. Fortunately, most of them occur on the bottom of the oceans, and therefore are not accompanied by catastrophic consequences.

List of catastrophic earthquakes that occurred in the 20th and 21st centuries (see Table 1):

Table 1. List of catastrophic earthquakes.

Table 1. List of catastrophic earthquakes (Continued).

Despite numerous time studies of earthquakes, no one can claim that their causes have been thoroughly studied and do not require further research. Based on the nature of the processes at the source of earthquakes, certain types of earthquakes are distinguished.

The main types of earthquakes are tectonic, volcanic and man-made (see Table 2).

Table 2. Main types of earthquakes.

Scientists who study earthquakes record them all over the world. Scientists record vibrations using seismographs (these are instruments that record seismic vibrations). They consist of a pendulum suspended inside a housing on a spring, and a recording device). The readings from seismographs installed in remote locations are transmitted to the central seismic station. At the moment, seismographs are modern electronic devices. Such devices record vibrations in digital form. The recorded data is then converted into a graphical record of the seismic wave, called a seismogram. Simple, non-electronic seismographs have a pen or other writing device attached to a heavy weight. The weight with the feather hangs on the support frame. A rotating cylinder is mounted on the same frame, fixed in the ground. When the soil vibrates, the frame and cylinder also vibrate, but the load and feather remain motionless. Therefore, the pen writes a wavy curve on the cylinder - a seismogram. To understand how a simple seismograph works, tie a small but weighty weight, such as a bottle filled with liquid, to the end of a 1-meter long string. Take the other end of the string and lift the weight off the floor. If you move your hand back and forth very quickly, the weight will remain almost motionless. During an earthquake, the weight and pen of a seismograph behave in exactly the same way.

A couple of minutes later, as soon as an earthquake occurs, seismic stations record the passage of seismic waves. From the first moment of an earthquake, such waves begin to rush in all directions from its source. They pass through the ground and around the entire circumference. Different types of waves move at different speeds. Therefore, by comparing the moments of arrival of waves of each type, it is possible to calculate how far away the earthquake epicenter is if there is no information directly from the scene. Because an earthquake can occur in a deserted place or damage communication lines. To detect the epicenter of an earthquake, information from several seismic stations located in different parts of the Earth is needed. To find out the location of the epicenter, knowledge from at least three stations is needed. A circle is drawn around each of them with a radius equal to the distance from it to the epicenter. The intersection point of the circles will indicate the epicenter.

In order to determine the strength of an earthquake, several scales are used.

The most famous is the Richter scale, created in 1935. This scale uses a device called a seismograph. A seismograph measures the magnitude of the waves produced by an earthquake. The magnitude, or strength, of an earthquake typically ranges from 1 to 8 on the Richter scale (although some giant earthquakes have recorded waves beyond the upper limit of the scale). Shock waves from a magnitude 1 earthquake can only be detected using special instruments; earthquakes with a magnitude of 8 cause large-scale destruction. An increase in points by one means an increase in the strength of the earthquake by 10 times. For example, a magnitude 5 earthquake on the Richter scale is ten times stronger than a magnitude 4 earthquake. New methods have recently been invented to measure earthquakes, including a method that measures what is called the intensity of the earthquake moment. The scale created by this method examines the size of the fault where the earthquake occurred and measures how much of the Earth's crust has shifted. The strength of an earthquake is also measured using the Mercalli scale. This scale takes into account the effect an earthquake has on people and buildings. On this scale, an earthquake can reach 12 levels of intensity. A Level 12 earthquake causes widespread destruction.

In Russia, it is customary to evaluate the intensity of fluctuations in MSK points (12-point Medvedev-Sponheuer-Karnik scale), in Japan - in JMA points (9-point scale of the Japan Meteorological Agency).

Intensity in points expressed as integers is determined by examining the area in which the earthquake occurred, or by interviewing residents about their feelings in the absence of destruction, or by calculations using empirically obtained and accepted formulas for a given area. Magnitude is determined from seismograms even at large distances from the epicenter.

In a broad sense, environmental consequences should be divided into social, natural and natural-anthropogenic. In each of the groups, direct and indirect consequences can be distinguished.

Currently, we know the direct manifestations of earthquakes on the earth's surface. This means that their direct impacts on the elements of the social organism, while the accompanying indirect phenomena at the level of micro and even macro anomalies of processes in the lithosphere and outside the lithosphere began to be studied quite recently.

The number of earthquake victims around the globe, although unevenly distributed over the years, is generally growing steadily, for the reasons stated above. Over the past 500 years, earthquakes on Earth have killed 4.5 million people. It turns out that earthquakes claim an average of 9 thousand human lives every year. And in the period 1947-1976, the average losses were 28 thousand people per year. From the point of view of environmental as well as social consequences, no less important is the fact that the number of injured is usually many times higher than the number of dead, and the number of those left homeless exceeds the number of direct victims by an order of magnitude or more. Thus, in areas of complete destruction of buildings, the number of victims can be 1-20%, and the number of wounded – 30-80%

The impact of seismic phenomena on the population includes both direct social damage (death of people, their physical or mental trauma, loss of shelter in conditions of disruption of vital systems, etc.). So is indirect social damage, the severity of which is due to a sharp change in the moral and psychological situation, the hasty movement of large masses of people, disruption of social ties and social status, a reduction in the ability to work and a drop in the productivity of labor of the survivors, partly diverted from their usual individual and social activities. A powerful earthquake, especially in large cities and densely populated areas, leads to disruption of life for a certain period.

As part of environmental problems, among the consequences often provoked by strong earthquakes, that is, secondary, it should be noted (against the background of damage and death of landscape and cultural monuments and disturbance of the habitat as such) such as:

-the occurrence of epidemics and epizootics,

-increase in diseases

-violation of population reproduction,

-reduction of the food supply (destruction of stocks, loss of livestock, disablement or deterioration in the quality of agricultural land),

- unfavorable changes in landscape conditions (for example, denudation of mountain slopes, collapse of valleys, hydrological and hydrogeological changes),

-deterioration in the quality of atmospheric air due to clouds of raised dust and the appearance of aerosol particles as a result of fires arising from earthquakes,

-decrease in water quality, as well as the quality and capacity of recreational and health resources.

The natural and man-made consequences of earthquakes affect the natural environment of the area affected by the earthquake as a result of disruption (destruction) of artificially created objects: Fires on objects of the anthropogenic environment; breakthrough of reservoirs with the formation of a water shaft below the dams; ruptures of oil and gas pipelines, oil spills, gas and water leaks; releases of harmful chemicals and radioactive substances into the environment due to damage to production facilities, communications, and storage facilities; violation of the reliability and safe functioning of military-industrial and military-defense systems, provoked explosions of ammunition.

The above list is not complete. Especially with regard to long-term consequences, some of which are still unknown to us.

It happens that tremors are accompanied by a clearly audible low rumble. In this case, the frequency of seismic vibrations lies in the range perceived by the human ear. And sometimes such sounds are heard even in the absence of shocks. They are quite common in some areas, although significant earthquakes are very rare. There are also numerous reports of glow occurring during strong earthquakes. There is no generally accepted explanation for this yet. During many strong earthquakes, in addition to the main shocks, foreshocks (preceding earthquakes) and numerous aftershocks (earthquakes occurring behind the main shock) are recorded. Aftershocks are usually weaker than the mainshock and can recur over weeks or even years, becoming less and less frequent.

Most earthquakes are concentrated in two long, narrow zones (see Table 3). One of them frames the Pacific Ocean, and the second stretches from the Azores east to Southeast Asia.

Table 3. Seismic earthquake zones.

There is also a smaller zone in the central part of the Atlantic Ocean, following along the Mid-Atlantic Ridge.

Among the areas where earthquakes occur quite often are: East Africa, the Indian Ocean and in North America the river valley. St. Lawrence and the northeastern United States.

Compared to shallow-focus earthquakes, deep-focus earthquakes have a more limited distribution. They have not been recorded within the Pacific zone from southern Mexico to the Aleutian Islands, and in the Mediterranean zone - west of the Carpathians. Deep-focus earthquakes are characteristic of the western edge of the Pacific Ocean, Southeast Asia and the western coast of South America. The zone with deep-focus sources is usually located along the zone of shallow-focus earthquakes on the continental side.

To begin with, it must be said that an earthquake forecast is a prediction of the time, place and strength of a future strong seismic event.

There is no scientific method by which earthquakes can be predicted. The danger of earthquakes lies in their suddenness. The following types of forecast are distinguished:

1. Long term
2. Medium term
3. Short

The least controversial is the long-term forecast, which smoothly merges with the tasks of zoning. It consists of observations of the appearance of zones of seismic stagnation, changes in the stressed state of the lithosphere, changes in its seismic transparency, observation of how individual small blocks gradually abandon their independence in their behavior and unite in the process of preparing one large impact. Recording observations of such processes sometimes provides information about the preparation of an earthquake a couple of months or years in advance.

A medium-term forecast makes it possible to be warned about a seismic event weeks or months in advance. It has practical specificity. This predictive level assumes a scenario for the development of the destruction process according to current observations of geophysical fields, changes in the slopes of the earth's surface, routine observations of the flow rate and chemical composition of water sources and deep water, oil and gas wells. Formalized criteria for assessing the statistical significance of each of the precursors and their complex are used. Based on established mainly empirical connections between the parameters of precursors and earthquakes, an assessment of the location and magnitude of the expected earthquake is made.

Progress in research on medium-term predictors is weak. As with long-term forecasting, scientists can be famous for specific results. But this is only an exception in the general flow of events.

Short-term forecast. Forecast with a lead time of a couple of hours or days. Almost all the methods described above remain valid here. At the same time, special attention is paid to activating the process of changing the stress-strain state.

Due to its great social significance, the reliability of short-term forecasts must be subject to the most stringent requirements. The responsibility of specialists and officials is especially high when declaring a “seismic alarm”. Because unnecessary delay can lead to the death of hundreds of thousands of people.

By monitoring changes in various properties of the Earth, seismologists hope to establish a correlation between these changes and the occurrence of earthquakes. Those characteristics of the Earth whose values ​​regularly change before earthquakes are called precursors, and deviations from normal values ​​themselves are called anomalies.

The main earthquake precursors currently being studied will be described below. (see Table 4).

Table 4. Main precursors of earthquakes.

Table 4. Main precursors of earthquakes. (Continuation)

Table 4. Main precursors of earthquakes. (Continuation)

Table 4. Main precursors of earthquakes. (Continuation)

To summarize, let's say that an earthquake is underground tremors and vibrations of the earth's surface that arise as a result of sudden displacements and ruptures in the earth's crust and upper mantle and are transmitted over long distances.

Strong earthquakes are catastrophic. The material damage of one devastating earthquake can amount to hundreds of millions of dollars. The number of weak earthquakes is much greater than the number of strong ones. Thus, out of hundreds of thousands of earthquakes that occur annually on our planet, only a few are catastrophic.

The territorial distribution of earthquakes is uneven. It is determined by the movement and interaction of lithospheric plates. The main seismic belt, in which up to 80% of all seismic energy is released, is located in the Pacific Ocean in the region of deep-sea trenches. The movement of lithospheric plates occurs there. Energy is also released in the Eurasian fold belt in places where the Eurasian plate collides with the Indian and African plates and in the areas of mid-ocean ridges under conditions of lithospheric stretching.

1. Boyko, S.V., Prokaten, E.V. General geology: textbook. allowance / S.V. Boyko, E.V. Prokaten [Text], - Krasnoyarsk: SFU Publishing House, 2014. - 328 p.
2. Platov N.A. Fundamentals of engineering geology [Text], - M.: INFRA-M, 2009

Internet sources:

1. Popov Yu.V. Lecture course “General Geology” [Electronic resource], – https://popovgeo.professorjournal.ru.
2. Earthquakes. Why do earthquakes happen [Electronic resource], – https://vse-sekrety.ru/550-zemletryaseniya-pochemu-proishodyat-zemletryaseniya.html

15, total, today

Report on the topic Earthquake 5th grade

An earthquake is a natural disaster accompanied by large vibrations of the earth. To move roads, asphalts, fields and other surfaces, a powerful force is needed that lives in the depths of our planet.

How an earthquake is formed

The Earth is a living planet in which certain processes constantly occur. Under the crust - one of the layers of soil - processes occur during which an earthquake can occur through vibrations of the crust. Most often, this activity is invisible to a person, and he does not feel it, but it also happens differently. The epicenter is the place where all vibrations of the earth begin and waves emanate from it. The science that studies these mechanisms is called seismology.

Varieties

Earthquakes are divided into several types.

Tectonic – the largest, most powerful. The waves from them spread over vast areas, the layers of the crust shift.

Volcanic - those that occur near active volcanoes. Relatively non-destructive, local.

Landslides are not strong earthquakes that occur due to the corrosive effect of water on rocks.

All earthquakes are classified according to the points of the scale invented by the German seismologist Richter. There are 10 of them:

1 – almost imperceptible.

2 – stronger than the previous one, but also not noticeable.

3 – tremors are felt only slightly.

5 – strong, can cause cracks and splits in structures.

6 – moderate destruction;

With a magnitude of 8.5, earthquakes are considered dangerous and destructive. There may be casualties and irreversible consequences.

Most often, such natural disasters occur in places where tectonic plates converge - this is the territory of Japan, the Far East, the Kuril Islands. And the most destructive ones are observed in South America. Islands in the Pacific Ocean, the Caucasus, and Crimea are also considered earthquake-prone places on Earth.

5, 6, 7 grade geography, life sciences

Geography lesson “Mountains. Earthquakes. Volcanic eruptions” (6th grade, correctional school)

Regional state budgetary special (correctional) educational institution for students and pupils with disabilities “Klyuchevskaya special (correctional) general education boarding school of the VIII type”

Geography lesson, 7th grade

Subject:

Mountains. Earthquakes. Volcanic eruptions.

Developed by:

Zolotareva I.N. teacher of biology and geography,

highest qualification category

With. Keys, 2014

Lesson topic: Mountains. Earthquakes. Volcanic eruptions.

Equipment: physical map of Russia, set of emoticons, handouts, task cards, projector, notebooks, textbooks.

Lesson Objectives:

Educational:

1. To consolidate knowledge about the shapes of the Earth's surface: mountains, to give an idea of ​​earthquakes, volcanoes, their structure, the causes of earthquakes and volcanic eruptions.
2. To form in students an idea of ​​the dangers and benefits of volcanic eruptions;
3. Help students understand why volcanoes and earthquakes are dangerous natural phenomena.
4. Form new concepts: magma chamber, crater, crater, lava.

Corrective and developmental goals:

1. Correction and development of analysis and synthesis processes by establishing the relationship between the Earth's surface and possible cataclysms occurring in its depths based on factual material.
2. Improve monologue speech skills by speaking and explaining various types of tasks.
3. Correct auditory and visual perception by working with a geographical map and diagrams.

Educational goals:

1. Develop the ability to work in pairs and in a team.
2. Foster a sense of responsibility and mutual assistance.
3. To cultivate a caring attitude towards the nature of one’s homeland, to form an idea of ​​the unity of the nature of planet Earth.

1. Organizing time.

- What a beautiful morning it is today. I'm glad to see you all. Today guests came to our lesson to see how active, attentive, and smart you are. I hope you will be like that.

— The lesson starts exactly on time and on time. Is everyone ready to answer and get A's? They sat down correctly, beautifully. So that you have enough strength for the lesson. We work diligently and listen carefully.

1. Psycho-emotional mood for the lesson

   .

— Guys, in what mood did you come to class? (emoticons)

Try to work so that your good mood does not leave you until the end of the lesson.

1. Repetition of covered material.

— Today I want to invite you to take a trip around our planet Earth.

- But before we go on a journey, let's collect our knowledge

, which we may need on the road.

— Let's tune in to search and creativity and start the lesson with a geographical minute

: We answer together together
“Yes” “No”:

1. Geography - the science of the nature of the Earth? (Yes)
2. The movement of air over the surface of the earth is precipitation (wind) - no;
3. Precipitation – snow, rain, hail – yes;
4. Hills are vast expanses of flat terrain (plains) - no;
5. Sides of the horizon - north, south, west, east - yes;

1. Now let's repeat the geographical terms, and for this we will carry out vocabulary work

   :

You have labels with terms on your desks. I will name the definitions, and you, who has this answer label on your desk, must show it to the whole class.

We studied all these concepts in previous lessons.

1. It can be different: warm, cold, cloudy, clear, wet and dry, windy and calm (weather).
2. This is a dangerous natural phenomenon - a thunderstorm.
3. Ice particles falling from clouds - hail.
4. The entire earth's surface that a person sees around him in a flat, open area is the horizon.
5. Sides of the horizon - showing with hands, children pointing from the cards.

Teacher:

So, the knowledge base has been collected. You can hit the road.

Physical exercise. (

The lesson uses an electronic physical exercise for the eyes.
)

1. Goal setting:

— The topic of our lesson: Mountains. Earthquakes. Volcanic eruptions.

— Guys, each of you must set a goal that you will work on in class.

— What goal did Yura set? (students name the goal for the lesson)

- Open your notebooks and write down the date and topic of the lesson.

1. Learning new material.

A) Mountains are vast elevations above the surrounding area.

They, like hills, have their own tops, bottoms and slopes.
The mountains are located one after another and form a mountain range. These are mountain ranges.
Their length can reach several hundred kilometers. (slide 1)

Mountain ranges consist of mountains of different heights. The highest of them can reach a height of 7000 meters above sea level . Between the ridges there are depressions - these are mountain valleys where people settle.

(slide 2)

By height, mountains are divided into low mountains - up to 1000 m above sea level, medium mountains - from 1000 to 2000 meters above sea level, and high mountains - above 2000 meters above sea level.

Low mountains have rounded peaks; high mountains often have sharp peaks and are covered with snow and ice.

High mountains are usually surrounded by low mountains and hills, these are called foothills.

(slide 3)

On the map, mountains are indicated in brown.

B) Earthquakes and volcanic eruptions often occur in the mountains.

Earthquakes and volcanic eruptions are the most dangerous natural phenomena.

(slide 4)

During earthquakes, cracks form in the ground, and entire sections of the land surface can go deep into the earth. Many people are dying, cities and villages are being destroyed. Several thousand earthquakes occur on our planet every year. The record holders for the number of earthquakes are countries such as Japan and Chile. Each of these countries experiences more than 1,000 earthquakes every year. (slides 5,6,7)

C) Now I will demonstrate to you one fascinating experiment.

And you will immediately guess what we will be talking about next in the lesson.

I take a small amount of ammonium dichromate. I set it on fire (observing all safety rules), when the combustion process occurs, it feels like (what?) a small volcanic eruption is happening. And How? Interesting? Scary?

— Guys, have you heard the word volcano

?

What associations does the word “volcano” evoke in you?

(children often answer “fire-breathing mountain”)

- Of course, you are probably interested in knowing what a volcano is? What structure does it have, how does a volcano erupt?

— The name of the word “volcano”

comes from the name of the ancient Roman god of fire
Vulcan.
(slide

According to ancient Roman myth, the god of blacksmithing, Vulcan, lived underground. His forge was always hot and loud. Sometimes God opened the doors to his kingdom and fire and smoke burst out. Subsequently, all places on Earth where fire-breathing mountains were found began to be called volcanoes.

.
Ancient peoples believed that a volcanic eruption was the great wrath of the gods.
Volcanoes are “windows” into the Earth. (slide 9)

A volcano is a mountain with a depression at the top (crater), through which magma, hot gases, water vapor, rock fragments, volcanic ash, and small pebbles erupt.

Volcanoes are found on different continents of the Earth. Among them there are many that are not only active, but also extinct. Inside the volcano, a hot substance is seething - magma, which can pour out at any moment.

During volcanic eruptions, hot streams of molten substances (magma) rush down the slopes of volcanoes, burning everything in their path.

From a volcano hole ( crater)

Clouds of smoke, gas, ash erupt, and hot stones fly out. The earth is burning, volcanic ash covers the surrounding area. (slide 10)

The most famous eruption in Europe remains the eruption of Mount Vesuvius, as a result of which the city of Pompeii and 2 other cities were destroyed within 2 days (Herculaneum, Stabia), 2000 people died, burned by lava. This catastrophic event was shown in his painting by Karl Bryullov “The Last Day of Pompeii” (slide of the painting)

There are about 800 active volcanoes on earth, which can go berserk at any moment. Look at the plaque, which shows the largest eruptions that killed a lot of people. (Largest volcanic eruptions - slides)

— What conclusion can we draw about whether volcanoes are dangerous? (children's answers)

- volcanoes are very dangerous, but they also bring us many benefits: in the vicinity of volcanoes, valuable metals (copper, silver, gold) and precious stones (sapphires, diamonds) are found; volcanic ash is an excellent fertilizer; in areas with active volcanoes, mineral springs are formed water.

Scientists who study volcanoes are called volcanologists.

1. Reflection.

- And now I propose to play a game that will test how you remember the material. Let's open the textbooks on page 33. On the board there are cards on which concepts and their explanations are written. It is necessary to correlate the names of concepts with their interpretation.

Magma is the hot substance inside a volcano;

A crater is a hole in a volcano from which clouds of smoke, ash, and gas erupt.

Mountains are vast elevations above the surrounding area.

Foothills are low mountains and hills.

Volcanologists are scientists who study volcanoes.

—

Now we will work in pairs to consolidate the material we have learned. (cards).

— What signs do you think can be used to determine that this is a volcano and not just a mountain? (A volcano has a crater, a crater, and a layered cone.)

1. Lesson summary.

— Have you achieved the goal that you set for yourself at the beginning of the lesson?

— I want to know how your mood changed at the end of the lesson? (emoticons)

— On your desks you have trees, and on the board there are 3 volcanoes:

1. Volcano of new knowledge,

2. Volcano of good mood

3. Volcano of labor and patience. Plant these trees on one of these volcanoes.

1. Assessment, grading for work in class (diaries).

2. Homework (in diaries)

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Report 3

An earthquake is perhaps one of the most terrible natural phenomena on Earth. People, devices, and technologies are powerless against it. The only thing modern technology can do is to anticipate some earthquakes and evacuate people in advance.

An earthquake is caused by the collision of tectonic plates. The epicenter of an earthquake can be deep underground or relatively on the surface. The deeper underground the epicenter is, the less shaking will affect the solid surface of the earth. If the epicenter is located at a distance of twenty to fifty kilometers, then this is already fraught with danger for the population. An earthquake is measured on a scale of twelve. Moreover, there is a fine line - only people feel earthquakes of magnitude three, but everyone else feels earthquakes of magnitude four. At five points, light objects move. Six to seven points cause the destruction of buildings. Further we go, worse it becomes. Ten-magnitude earthquakes turn structures into ruins. The worst thing is a magnitude 12 earthquake that destroys entire cities.

A seismograph is a device that allows you to determine the level of an earthquake. By the way, this same device helps predict an upcoming volcanic eruption.

Scientists have identified several signs that an earthquake is near:

• increased smell of gas, which is not natural for the area;
• restless behavior of animals and birds;
• sparkling wires that do not touch each other;
• spontaneous combustion of lamps in homes and offices;

In our country there are seismically dangerous places, for example, Kamchatka. In such areas there are huge precautions or emergency evacuation measures. Houses built in such places are built using special technologies in case of an earthquake.

An earthquake becomes especially dangerous if its epicenter is in water (ocean), which leads to a terrifying tsunami.

5th, 6th, 7th grade. Geography, life safety

What is an earthquake?

An earthquake is a shaking in the earth's crust. The more powerful the vibration of the earth's surface, the more powerful the vibrations of the earth's surface, they are perceived by humans. This natural phenomenon is not uncommon: it is celebrated every day in different parts of the planet. The vast majority of large tremors are recorded in the World Ocean. If the phenomenon were more typical for land, the number of casualties and destroyed objects would have increased many times over.

An earthquake can be called the completion of the process of movement of earth rocks. The movement of parts of the earth's crust is limited by the force of friction. When the maximum stress is reached, the rocks shift sharply with rupture, the friction force turns into motion energy, and as a result, the earth’s vibrations diverge radially. The fault point is called the focus, the point on the surface of the earth above the focus is the epicenter. Moving away from the epicenter, the oscillations gradually weaken. The underground wave can move at speeds of up to 8 km per second.

The duration of the oscillations is approximately the same, it takes about 30 seconds, and does not depend on the causes of the rupture, the characteristics of the affected area and other factors. But there were cases when the tremors lasted up to 3 minutes.

Signs of an earthquake can be not only the readings of seismic instruments, but also specific changes in the environment. The main precursors of earthquakes are:

• restless behavior of domestic and wild animals (many animals are able to sense the approach of a disaster, they try to leave the epicenter and the surrounding area, heading to a safe place);
• the appearance of special clouds in the sky that look like long stripes;

  

• changes in water levels in water sources;
• problems in the operation of mobile and electrical devices.

Not all areas of the globe are affected by earthquakes. Oscillations of the earth's crust are possible only in areas called seismic belts. There are two main belts: Pacific and Mediterranean. The Arctic, West Indian, and East African belts are also distinguished. The last three account for 5% of all tremors recorded on the planet.

About 80% of earthquakes are observed in the Pacific belt, which rings the shores of the Pacific Ocean. Moreover, catastrophic seismic processes occur every 100–150 years. The Mediterranean belt accounts for 15% of tremors; catastrophes occur every 250–300 years.

Since earthquakes can only occur in seismically active areas - tectonic fault zones, the population living in flat areas within the tectonic plate can be calm about their lives and property. On platform plains, earthquakes are extremely rare; they occur once every 600–800 years.

Australia is the only continent that is not located in the zone of lithospheric junctions. There are no mountainous areas or active volcanoes on the mainland, therefore earthquakes are impossible. Also, weak seismic activity is typical for Antarctica and Greenland. These areas of land are covered by a thick layer of ice, which prevents underground vibrations from appearing on the surface.

In Russia there are both seismically safe and dangerous areas. The following mountainous areas are considered dangerous:

• Altai;
• Caucasus (especially the northern part);
• Far East;
• Mountainous regions of Siberia (mainly the eastern part);
• Sakhalin;
• Kuril and Commander Islands.