Earthquake refers to the surface vibration caused by the release of energy due to the dislocation and fracture of rock mass in the earth's crust. Rock rupture produces seismic waves. When the seismic waves reach the surface, the ground vibrates. This is earthquake. Let's take a look at the reasons why earthquakes occur on the earth. Welcome to check it!
What caused the tectonic earthquake?
1. Continental drift theory
Plate movement is the main factor inducing tectonic earthquakes! When it comes to plate motion, we must first understand that the German geophysicist Alfred Wigner upgraded Abraham otlius's theory of continental division into the theory of continental drift! Of course, it was completely unacceptable in the early stage. After all, we can't accept that the solid ground under our feet is drifting! Although Wegener didn't find enough evidence at that time, Wegener's contribution to the theory of continental drift was really established in the 1960s with the discovery of evidence of seabed expansion at the bottom of the oceans!
Distribution of six global plates
2. What causes the continental drift?
To understand this problem, we must understand the geophysical structure!
The solid ground under our feet is only the thin crust of the earth, and deeper underground, the heat generated by the decay of reflective materials and gravitational collapse energy in the earth's interior heats the rock layers hundreds of kilometers deep to a molten state, which is commonly known as magma, while the magma flows slowly inside under the action of the earth's rotation, resulting in complex magma dynamics, Under the action of liquid viscosity, the rotation speed of the inner and outer layers is different, which is the basis of plate motion! Another important reason is that the thickness of the crust is not uniform, which is another important reason for the discovery of submarine expansion during the cold war between the United States and the Soviet Union!
The continuously emerging crust at the bottom of the ocean is the first driving force of the compression plate movement, which will lead to many geological movements, such as plate sliding, plate dislocation, plate re entering the lava circle cycle, etc!
The most intuitive manifestation of these movements is continental drift! In fact, it took more than a billion years to split the whole pan continent or United ancient land into the current seven continents!
It seems harmless to humans and animals, doesn't it? In fact, this is not the case at all, because the movements between plates will squeeze, shear and stretch each other, so many mountains have long been built.
This is far from over. The resulting plate edge and various geological defects inside and outside the plate lead to various rock fractures, formation deformation and stress accumulation, etc. have just begun!
3、 Tectonic earthquake
Tectonic earthquakes are divided into the following types:
1. Plate marginal type
2. Plate internal fracture type
3. Graben rift type within plate
In fact, these three types are relatively easy to understand. When the edge is directly impacted, the distribution of global earthquakes and volcanic belts is directly related to the connecting parts of plate edges!
What if the earthquake comes
We all know that earthquake, like wind, rain and lightning, is a natural phenomenon and an objective law. With the progress of science and technology, people's prevention and response methods to earthquake disasters are also increasing.
Once we really encounter an earthquake, what should we do?
First of all, don't panic and don't move blindly. Judge whether the earthquake is large, small, near or far according to the feeling. In general, near earthquakes move up and down first, and then shake left and right, while far earthquakes only shake back and forth, left and right. If it is a small earthquake or a distant earthquake, the houses we live in now basically have earthquake resistance capacity, so there is no need to panic.
Secondly, we should take correct methods to avoid earthquakes.
In different places, there are different ways to avoid earthquakes. Let's talk about how to avoid earthquakes in schools, homes and public places.
How to avoid shock in school:
Safety tips: 1. Follow the teacher's command in all actions; 2. Students should take care of each other, and big students should take care of small students; 3. Shock absorber under the desk and evacuate in order. Don't crowd.
Suppose we are having a class in the classroom and suddenly there is an earthquake, what should we do?
First of all, we should lie down, squat or sit down, hide our head under the desk and beside the podium, and never run around. Try to curl up and lower your weight. Grab a solid object such as a table leg. Protect the head and neck, eyes and cover the mouth and nose.
After the earthquake stops, you should evacuate in order immediately under the command of the teacher. When evacuating, put your schoolbag on your head and keep a certain distance between the front and rear students. Especially at the door of the classroom, stairwell and other narrow places, we must slow down, find students who fall, help each other, and inform the students behind in time to avoid congestion.
After running outside, you must hide in an open place as far as possible, and there is no place easy to fall around and on your head.
If we are on the playground or outdoors, we can squat in place, protect our heads with both hands, and pay attention to avoiding tall buildings or dangerous objects. Never go back to the classroom because you forgot something.
How to avoid shock at home:
Safety tips: 1. Hide first and then run. Don't run first; 2. Hide in a firm place (under the bed, in a small room, where there is support) 3. If you have time, open the door first and turn off the gas, power, etc.
During shock absorption, you should avoid nearby according to your position during the earthquake, and then withdraw to a safe place after the vibration stops. Hide under or next to objects that are strong, not easy to dump and can cover your body, such as tables, beds, etc. you can also run quickly to rooms with smaller bays and supports, such as kitchens, bathrooms, etc.
If you have time, open the door first to ensure smooth passage; Turn off the gas switch and electric switch.
During shock absorption, climb down to minimize the center of gravity of the body, face down, do not press the mouth and nose, and grasp the firm objects around you at the same time. You can also squat or sit down and curl your body up as much as possible. Pay attention to protect the head and neck. Protect the head and back neck with your hands. When possible, put objects around you on your head and close your eyes to prevent foreign body injury.
3、 How to avoid earthquakes in public places:
Safety tips: 1. Follow the instructions of the staff; 2. Don't rush to the exit and keep a distance from the person in front; 3. In case of congestion, unbutton your collar and cross your hands in front of your chest to protect your chest.
After the earthquake, if there is an emergency shelter nearby, you should rush to the shelter under the guidance of adults.
Earthquake emergency shelters are generally built on parks, green spaces, playgrounds and squares, which have the basic functions of emergency response. For example, emergency command, emergency material distribution, emergency shelter, emergency toilet, etc.
After the earthquake, we should also pay attention to the following problems:
Don't rush to the stairway, it's easy to squeeze.
Don't light a light casually, because there may be flammable and explosive gases in the air.
Don't be in a hurry to make a phone call, so as to avoid line congestion and affect disaster relief command and communication.
Identify and eliminate earthquake rumors
Because of the huge disaster of the earthquake, it is easy to make people panic about the earthquake. At this time, the earthquake rumors appeared and spread quickly. The harm of earthquake rumors is very great. It may not only disturb our study, production and life, but also disturb social stability and order.
Rumors often have the following characteristics:
1. The magnitude of the "predicted" earthquake is very large, and the occurrence time and earthquake are very specific. For example, an earthquake will occur in "a certain city" and "a few months and days".
2. It is said that foreigners, an expert or an earthquake organization made a prediction.
3. A forecast with the color of feudal superstition or accompanied by bizarre legends.
The reason why earthquake rumors have a market is that earthquake prediction is a worldwide scientific problem, which is still in the exploratory stage.
China's earthquake prediction is at the leading level in the world. It has successfully predicted earthquakes such as Haicheng, Liaoning Province. However, at present, we can only predict some types of earthquakes to a certain extent, but we can't predict all earthquakes. Especially the impending earthquake forecast is far from being as accurate as the weather forecast.
The government has the authority to publish earthquake prediction in China, and no other unit or individual has the right to publish earthquake prediction information. Article 16 of the law of the people's Republic of China on earthquake prevention and disaster reduction stipulates that the State implements a unified release system for earthquake prediction.
Therefore, when the earthquake news comes, remember the most basic one; Earthquake prediction news, only listen to the government.
To deal with earthquake rumors, we should "do not believe, do not spread and report in time".