Earthquakes. Causes of an earthquake and its possible consequences subject: life sciences - Lesson

In this lesson we will learn what earthquakes are, how strong they are, and what areas are called seismically active.

Additional materials for the lesson:

• Material from Wikipedia - the free encyclopedia. Seismograph https://goo.gl/OvQ9ef
• Material from Wikipedia - the free encyclopedia. Seismic wave https://goo.gl/ZfTgsW

Topic: Earth

Lesson: Earthquakes

-Natural disasters- these are various natural phenomena that cause sudden disruptions in the normal functioning of the population, as well as destruction and destruction of material assets. They often have a negative impact on the environment. Natural disasters usually include earthquakes, floods, mudflows, landslides, snow drifts, volcanic eruptions, landslides, droughts, hurricanes, and storms.

Earthquake- these are seismic phenomena that arise as a result of sudden displacements and ruptures in the earth's crust or upper part of the mantle, transmitted over long distances in the form of sharp vibrations, leading to the destruction of buildings, structures, fires and human casualties.

Rice. 1. Consequences of the earthquake ()

Earthquake source- the area of ​​occurrence of an underground shock in the thickness of the earth's crust or upper mantle, which is the cause of an earthquake.

Rice. 2. Source and epicenter of the earthquake ()

Epicenter of the earthquake- this is the projection of the center of the earthquake source onto the earth's surface. Around the epicenter of an earthquake, as a rule, is the area of ​​the largest earthquakes.

A seismograph is used to record earthquakes. - a special measuring device that is used to detect and record all types of seismic waves.

Rice. 3. Seismograph ()

Now let's look at how seismologists find out about an upcoming earthquake.

Rice. 4. Signs of an impending earthquake

By method of education earthquakes are divided into 4 types:

1. Tectonic occur during movements along a fault in the earth's crust. Sometimes deep faults come to the surface. The maximum recorded value of seismogenic displacements along the fault is 15 m.

2. Volcanic occur as a result of sudden movements of magmatic melt in the bowels of the Earth or as a result of the occurrence of ruptures under the influence of these movements.

3. Landslide occur during the development of large landslides, collapse of the roof of mines or underground voids.

4. Artificial (technogenic) may arise due to the filling of deep, more than 10 m reservoirs, injection of water into wells; during the formation of underground cavities due to mining, mining and high-power explosions.

Earthquake intensity- a measure of the magnitude of the shaking of the earth's surface during an earthquake in the area covered by it. In Russia and the USA it is measured using a 12-point modified Mercalli scale.

Rice. 5. Mercalli scale ()

What to do during an earthquake

When you feel the vibrations of the building, see the swaying of lamps, the fall of objects, hear an increasing rumble and the sound of breaking glass, do not panic (from the moment you feel the first tremors to the vibrations that are dangerous for the building, you have 15 - 20 seconds). Quickly exit the building, taking documents, money and essential items. When leaving the premises, take the stairs rather than the elevator. Once outside, stay there, but do not stand near buildings, but move to an open space.

If you are forced to stay indoors, then stand in a safe place: near an internal wall, in a corner, in an internal wall opening or near a load-bearing support. If possible, hide under a table - it will protect you from falling objects and debris. Stay away from windows and heavy furniture.

Do not use candles, matches, or lighters - a gas leak may cause a fire. Stay away from overhanging balconies, cornices, parapets, and beware of downed wires. If you are in a vehicle, remain in an open area, but do not leave the vehicle until the shaking stops. Be prepared to assist in rescuing other people.

What to do after an earthquake

Provide first aid to those in need.

Free those trapped in easily removable rubble.

Do not approach or enter visibly damaged buildings. Be prepared for strong aftershocks, as the most dangerous are the first 2 to 3 hours after an earthquake. Do not enter buildings unless absolutely necessary.

The earth's crust is heterogeneous, it consists of individual tectonic plates.

Rice. 6. Tectonic plates ()

These plates are in constant motion. It is at the junctions of these plates that earthquakes occur; such areas are called seismically active.

1. Melchakov L.F., Skatnik M.N. Natural history: textbook. for 3.5 grades avg. school - 8th ed. - M.: Education, 1992. - 240 pp.: ill.

2. Bakhchieva O.A., Klyuchnikova N.M., Pyatunina S.K. and others. Natural history 5. - M.: Educational literature.

3. Eskov K.Yu. and others. Natural history 5 / Ed. Vakhrusheva A.A. - M.: Balass.

2. Rules of conduct during an earthquake ().

1. What is the source and epicenter of an earthquake?

2. What types of earthquakes are there?

3. Describe the 12-point Mercalli scale.

4. * Imagine that you are a seismologist and predicted an earthquake. How will you know about an upcoming earthquake? How will you characterize it after it happens?

Life Safety Lesson Summary

in the 7th grade

on this topic

"Earthquakes".

"Earthquakes".

The purpose of the lesson:
During the lesson, consider an earthquake as one of the natural emergencies.
Tasks:
1. Provide students with the necessary information about the causes of earthquakes and their consequences.
2. Improve skills in working with test material in order to prepare for passing exams in a new form; use interdisciplinary connections for conscious perception of the material.
3. Foster feelings of mercy and compassion for people in emergency situations; continue to form students’ beliefs in the need for knowledge.

Materials and equipment.
1. Chalk diagram “Classification of earthquakes based on the causes of their occurrence”
2. Geographical map of the continents
3. A selection of color illustrations from the magazines “Civil Protection”, “Fundamentals of Life Safety”, etc.
Tests, cards.

During the classes:
1.Introductory part
Today in class we continue to talk about emergency situations.
What is an emergency?
- The situation is dangerous for health and life.
What groups can all emergency situations be divided into?
- Technogenic, social and natural nature.
Give examples of emergencies of different nature.
Which organization deals with emergencies?
- Ministry of Emergency Situations.

How does EMERCOM stand for?

Ministry of Emergency Situations.
Who heads the Ministry of Emergency Situations?
In the last lesson, we talked about natural emergencies - hurricanes, storms, tornadoes and the actions of the population with the threat of and during hurricanes, storms and tornadoes.
Now you need to test your knowledge
(distribution of tests and cards on the topic - (hurricanes, storms, TOrnadoes)
View results.
Today we are starting to study another natural phenomenon that can lead to an emergency
Now listen carefully to the poem and think
- What natural phenomenon is this poem about?
Reading a poem out loud
The whole earth shook, a ridge of clouds rushed.
The shaking of the earth carried away cities...
All the shackles of heaven were able to open.
The joints of the earth were brought down by rampant shaking,
He squeezed the poor land into such a vice,
That huge rocks were broken into pieces...Nizami
About the earthquake.
Write the topic of the lesson in your notebook.
We will cover the following questions in class:
1What is an earthquake?
2. Causes of earthquakes.
3. Consequences and forecasting of earthquakes.

2. Work on educational question No. 1:
What are earthquakes?
How do you understand the word earthquake?
This is a phenomenon when the earth shakes.
EARTHQUAKES - vibrations of the Earth caused by sudden changes in the state of the planet's interior. These vibrations are elastic waves propagating at high speed through the rock mass.
Distinctive features:

After listening to all the answers, I ask students to define an earthquake. Students name different definitions: an earthquake is a rupture of the earth's surface; an earthquake is the destruction of buildings and structures; an earthquake is a natural disaster.
If students were unable to give an exact definition, then I ask them to find the correct answer in the textbook, or I myself give the correct definition of an earthquake. Students read and write the definition of an earthquake in their notebooks.

Earthquakes- These are tremors and vibrations of the earth's surface that arise as a result of sudden displacements and ruptures in the earth's crust or upper mantle and are transmitted over long distances in the form of elastic vibrations.

The intensity of earthquakes is assessed in seismic scores; magnitude is used for the energy classification of earthquakes.
In the following lessons we will examine in more detail the main characteristics of earthquakes.

Every year, instruments record several hundred thousand earthquakes. People feel only about 10 thousand earthquakes, of which about 100 are destructive.
There is a part of the globe that can be considered free from earthquakes - this is Antarctica (write in your notebook). We can say that this is a kind of seismic mystery, since Antarctica has both young mountains and active volcanoes.
According to scientists, all the earthquakes that occurred in our century alone claimed more than 1 million lives. And in the entire history of mankind, about 75 million people died from earthquakes.
- Guys, why are we studying this topic in life safety lessons?
- Where do earthquakes most often occur and why?

Working on educational question No. 2
Causes of earthquakes.
In the depths of the earth, complex processes of energy accumulation are constantly taking place, the release of which causes a seismic shock. The moment of release of this energy, which is commonly called

the energy of tectonic processes is associated with the movement of the plates into which the earth’s crust is divided. Three phenomena can occur at the boundaries between plates: in some cases the plates move apart, in others they shift or slide one against the other.
At the point where two plates collide, the earth’s surface deforms and accumulated energy is released. Earthquakes of this type are called tectonic. Sometimes earthquakes occur in the internal parts of plates - so-called intraplate earthquakes. They arise due to the development of deformation (energy accumulation) in the slabs caused by pressure at their edges.
The main plates of the earth's crust are: (write in notebook)
- American, Antarctic, African, Eurasian, Indian and Pacific In total, there are about 20 plates on which entire countries, continents, seas and oceans are located. The joint zones of these plates are known. This is where the areas of the most active seismic phenomena are located.
The chalk diagram (Scheme No. 1: Classification of earthquakes according to the reasons for their occurrence) should be prepared in advance on the board, closed from the attention of students before starting work on the second educational question.
Earthquakes:

3.Tectonic
4.Volcanic
5. Landfall

Although numerous studies have been carried out since ancient times, it cannot be said that the causes of earthquakes have been fully studied. Based on the nature of the processes at their sources, several types of earthquakes are distinguished, the main ones being tectonic, volcanic and man-made.
Volcanic earthquakes occur as a result of sudden movements of magmatic melt in the bowels of the Earth or as a result of the occurrence of ruptures under the influence of these

movements.
Man-made earthquakes can be caused by underground nuclear tests, filling reservoirs, oil and gas production by injecting liquid into wells, blasting during mining, etc. Less powerful earthquakes occur when cave vaults or mine workings collapse.

Another category is formed by landslide earthquakes, when the collapse of a mine roof or underground voids causes the formation of elastic waves. Landslide earthquakes also include earthquakes that occur during the development of large landslides.

The most powerful and dangerous are tectonic and intraplate earthquakes. If there is one earthquake, then the likelihood that another one will soon occur in the same area is high. In other words, strong earthquakes most often entail aftershocks,
Earthquakes most often occur in certain areas. The earthquake zone surrounding the Pacific Ocean is called the Pacific Belt; About 90% of all earthquakes in the world occur here. Another area is the Alpine belt, stretching from the Mediterranean east through Turkey, Iran and northern India, where about 5-6% of all earthquakes occur. The remaining 4-5% of earthquakes occur along mid-ocean ridges or within plates.

Working on question No. 3
Consequences and forecasting of earthquakes.
Registration of earthquakes.
To detect and record seismic waves, special devices - seismographs - are used.

The first seismograph appeared in China in 132. The famous Chinese scientist Zhang Heng created it in Xi'an during the Han Dynasty. In a large vessel (180 cm in diameter) he placed a pendulum that could swing in eight directions. Eight dragons, each with a ball in its mouth, were secured around the edges of the vessel. When the shock of the earthquake caused the pendulum to swing, the ball fell out of the dragon's mouth and fell into the open mouth of the toad sitting below. In that

At that moment, the device made a sound, notifying observers that an earthquake had occurred. Depending on which of the toads got the ball into their mouth, it was possible to determine in which direction it happened. The device worked so well that it could detect distant earthquakes that were not felt by the observers themselves.

Modern seismographs are complex electronic devices. They use the property of inertia. The main part of the seismograph is the inertial body - a load on a spring. This load is suspended from a bracket, which is rigidly fixed in solid rock and therefore moves during an earthquake. A paper tape drum is also attached to the seismograph body. When the soil vibrates, the pendulum's weight lags behind its movement. Seismic waves are recorded with a pen on a moving paper tape. A record of ground shaking is called a seismogram.
Seismographs record more than a thousand earthquakes on Earth every day. Fortunately, many of them are so weak that they do no harm.
Recordings from two or more seismographs help seismologists determine where an earthquake occurred and measure its strength.
Modern technology allows you to record and photograph the most striking moments of an emergency, look and hear about them.

The most powerful earthquakes are sometimes felt at distances of more than 1,500 km from the source and can be recorded by seismographs (special highly sensitive instruments) even in the opposite hemisphere. The area where vibrations originate is called the earthquake source, and its projection onto the Earth's surface is called the earthquake epicenter.
The sources of most earthquakes lie in the earth's crust at depths of no more than 16 km, but in some areas the depths of the sources reach 700 km. Thousands of earthquakes occur every day, but only a few of them are felt by humans.
On December 7, 1988, in Armenia, at that time one of the republics of the Soviet Union, an earthquake killed about 25 thousand people, the second most populous city of Leninakan, the cities of Spitak, Kirovkan and

another 60 settlements (see photo on p. 73).

On May 28, 195, a powerful underground shock razed the small town of Neftegorsk on Sakhalin Island (see photo on p. 73). This earthquake is one of the most destructive in Russia this century.

On August 17, several cities in Turkey were left in ruins as a result of an earthquake, and a month later, on September 21, a tragic earthquake occurred in Taiwan.

Consequences of earthquakes.
- Tell me, what are the most terrible consequences caused by earthquakes?
- What can we do to help ourselves in this situation?
- So, what conclusion do we draw? – The most important thing is to have knowledge, because your life or those close to you may depend on it.

2. The final part of the lesson
Check of knowledge.
1-What is an earthquake? Give a definition.
Earthquakes are tremors and vibrations of the earth's surface that occur as a result of sudden displacements and ruptures in the earth's crust or upper mantle and are transmitted over long distances in the form of elastic vibrations.
2-Name the classification of earthquakes based on their causes
emergence
1.Earthquakes of natural origin
2.Earthquakes caused by human activity
3.Tectonic
4.Volcanic
5. Landfall
6. Edge (at the edges of tectonic plates)
7. Intra-plate rock bursts, landslides, filling reservoirs, pumping water into wells, nuclear weapons testing
3- Name a part of the globe that can be considered free from earthquakes - Antarctica
4-The main plates of the earth's crust are:
American, Antarctic, African, Eurasian, Indian

and Pacific.
5- What special seismograph devices are used to detect and record seismic waves?
6- Where the first seismograph appeared - in China in 132
7- What major earthquakes have occurred in recent years?
Earthquakes in Taiwan, Leninakan (Armenia), Neftegorsk, Turkey, etc.

What new things did you learn in this lesson?

I draw a conclusion about the level of knowledge acquisition by students. Next, I grade the lesson for the most active students, sum it up, and assign homework.

Fundamentals of life safety. 7th grade Petrov Sergey Viktorovich

4.4. Consequences of earthquakes

The consequences of earthquakes are extremely dangerous. If to primary factors of damage While earthquakes can practically only be attributed to sharp tremors and vibrations of the earth's surface, the secondary factors are very diverse. Conventionally, they can be divided into natural and associated with human activity.

Typical damage to buildings as a result of a 7-8 magnitude earthquake

Artist Karl Bryullov

"The last day of Pompeii"

Earthquake in Leninakan (Armenia, December 1988)

Railway destroyed by earthquake

Earthquakes cause dangerous geological phenomena - stretching, flow and subsidence of the soil, wide cracks in it, landslides, rockfalls, large landslides, avalanches, mud flows, tsunamis and mudflows.

Consequences associated with human activity include damage and destruction of buildings, fires, explosions, emissions of harmful substances, transport accidents, and failure of life support systems. As a result of a breakthrough in hydraulic engineering and water supply structures, floods, including catastrophic ones, are possible.

When assessing the degree of impact of earthquakes on humans, it is necessary first of all to say that strong earthquakes entail massive loss of life. Thus, as a result of the earthquake in the city of Neftegorsk, out of approximately 2,700 residents, more than 1,800 people died. Other serious consequences of strong earthquakes are injuries (bruises, fractures, cuts, compression). In addition, under the influence of the dangers they have experienced, the loss of loved ones, housing and property, many of the victims experience severe mental shocks and disorders, cannot react correctly (adequately) to ongoing events, and lose their ability to work.

Often, the immediate consequence of an earthquake is panic, during which people, in fear, commit absurd and dangerous actions for themselves and those around them and cannot meaningfully take measures for self-rescue and mutual assistance. Panic is especially dangerous in crowded places: in enterprises, medical, educational and children's institutions, dormitories, and public places.

Injuries and deaths occur mainly due to damage from debris from destroyed buildings, structures, structures and falling objects, as well as as a result of being in rubble and due to the lack of timely assistance. It is also possible to suffer from dangerous geological phenomena accompanying an earthquake and from secondary factors (tsunamis, fires, industrial and transport accidents, damaged engineering and energy networks).

Damage to buildings begins with earthquakes of magnitude 6-7. At 8 points, small-block buildings develop cracks in the main walls and collapses of plaster; large-block - wide cracks along the perimeter of the blocks, cracks in the blocks; panel - cracks in the joints of panels, thin cracks in places where hinged panels adjoin the frame, as well as between these panels; Damage to partitions occurs in all buildings.

Fires occur due to the destruction of furnaces, damage to electrical networks, fuel and gas storage and communications, and damage to technological equipment that uses flammable substances.

Emissions of radioactive, chemically hazardous and harmful substances occur due to the destruction or damage of their storage facilities, communications, technological and research equipment at nuclear power facilities, the chemical industry and other industries, in scientific institutions and public utilities.

Transport accidents and disasters occur as a result of the direct impact of seismic waves on vehicles and the destruction of elements of transport communications.

Disruption of the functioning of life support systems, destruction or damage to sewerage facilities and communications, heat, energy and water supply, material supply facilities and trade networks, communication systems leads immediately after the earthquake to a crisis in providing the population and surviving enterprises with everything minimally necessary for life and activity.

Where do most earthquakes occur? If we look at a map of the globe indicating the areas with the most frequent earthquakes, we will find a wide ribbon rising up and down across the entire surface of the Earth. There are no earthquakes in some areas

Consequences of a knife fight Author: Alexey Anushkin aka Relikt (Narva, Estonia) Published with the permission of the author. I immediately ask you to take the photographs seriously. The people depicted on them are real characters who actually suffered quite seriously. Why do I