Chapter 4 4 epicenter
When an earthquake occurs, there are mainly two kinds of seismic waves that people can feel and suffer from, namely P waves (longitudinal waves) and S waves (shear waves) that professionals often say.Each type moves at a different spread and speed. The P wave moves the fastest, with a propagation speed of 8-9 kilometers per second, and reaches the ground first.In the epicenter area, the P wave makes people feel up and down bumps, causing little damage, and it is a signal to people that an earthquake has occurred. The movement speed of S wave is slower than that of P wave, usually 4-5 kilometers per second on average, and it is a very destructive wave that reaches the surface after P wave.What it makes people feel is the shaking of front and back, left and right, and the collapse of buildings, etc., which is a wave that directly endangers the safety of people's lives and properties.Therefore, family and self-help is mainly within a few seconds after the P wave reaches the ground.When the P wave arrives, an earthquake should be recognized immediately.If we can quickly evade to a safe place within ten seconds before the shear wave arrives and causes damage, it will provide us with the last chance to save ourselves.Generally known as the 12-second self-rescue opportunity.
In addition, the ground sound and light are also early warning signals of major earthquakes.Many ground sounds appeared within 10 minutes before the earthquake, and the loudest sound was more than ten seconds before the earthquake.According to reports from the people in the earthquake area, when the earthquake was imminent, they first heard the sound of "whirling" wind, followed by "booming", and then "dongdong". After that, the ground began to vibrate. Caused by low-altitude electrostatic field.Its shapes are ribbon, flake, spherical, columnar, and the colors are mostly blue, white, red, and yellow.The ground fretting may be caused by stress waves caused by fault pre-slip in the source area immediately before the earthquake.
Among the survivors of previous major earthquakes, many people observed these abnormal phenomena of impending earthquakes, judged that a major earthquake was coming, took measures to avoid danger quickly, and escaped the disaster.For example, before the Haicheng earthquake, the No. 31 express train ran to the Tangwangshan station in the earthquake area at 19:36. The train driver suddenly noticed that a large area of blue and white flashes appeared from the ground to the sky in front of the front of the train.The driver knew about earthquakes, realized that it was ground light, and judged that an earthquake was coming. He decelerated decisively and calmly. During the deceleration process, an earthquake occurred at 19:36:07.Due to the low speed, there was no accident and the train stopped safely.According to the survey of some survivors of the Tangshan earthquake, before the earthquake, many people noticed the sound of the ground, the light of the ground and the slight movement of the ground. Among them, 5% judged that the earthquake was coming, and quickly escaped from the building to save their lives; People didn't think of the earthquake immediately, they acted slowly, and lost this last chance of escape.
The above-mentioned cases tell us that we must learn the bloody lesson and popularize the knowledge about the 12-second self-rescue opportunity in order to minimize the earthquake casualties.
1. One-story house.Generally speaking, bungalows are much safer than buildings. If improper measures are taken, it will also cause greater casualties and losses.If you hear the sound of the ground and see the light of the ground before the earthquake, you can evacuate quickly.Once evacuated, do not return. For example, Li Zhifen from the Tangshan Iron and Steel Company, who heard the ground noise before the Tangshan earthquake, fled immediately. After running away, she thought that her sister was still sleeping on the bed. When she returned to rescue her, she was also smashed and buried in the house.If you feel the ground shaking and you cannot evacuate in time, it is best to take cover under sturdy furniture.The roof of the bungalow is lighter, and it is safer to hide under the bed or table.
If you live in a bungalow, you can quickly run out the door.If you live in a building, don't hide under the table or bed, but use a posture lower than the height of the table or bed, hide next to the table or bed, or hide in a room with a small span, such as a bathroom or kitchen, or hide in a room with a small span. Support triangular space.Pay attention to protect the head to prevent injury from foreign objects; cover the mouth and nose with a mask, and keep the body in a low position.Be careful not to jump off buildings or windows, so as not to fall or get hurt by glass; don’t go on the balcony, don’t take the elevator, don’t go down the stairs, don’t run around, and don’t crowd with people, these places are prone to collapse and squeeze Trampled.Especially for felt earthquakes, it is especially necessary to prevent blind actions and follow instructions, otherwise greater losses will be caused.All indoor personnel must evacuate as soon as possible after the initial shock, and stay in squares, parks and other places to avoid aftershocks.
Please pay attention to the black bold part above, because the information we have learned before is to hide under the table and the bed. However, according to the experience of Doug Karp, the US International Search and Rescue Captain, this practice is not safe.
Here, citing the article about this description, as a supplement:
The US International Search and Rescue Captain teaches you the correct hiding position.Correct Earthquake Survival Method
Doug Karp is the captain of the United States International Search and Rescue. Since 1985, he and his team members have participated in the relief work of 79 major disasters around the world. He once climbed into nearly 700 buildings damaged by earthquakes and explosions. Trapped survivors and the remains of victims were searched in the badly collapsed building.In addition to participating in the Kobe earthquake in Japan two years ago and the bombing of the federal building in Oklahoma City in the United States, he has not been absent from the major disaster relief in the international news in the past 12 years.
Before he left China on the 19th of this month, in addition to the Chinese Taiwan Search and Rescue Corps invited him to speak, the American Institute in Taiwan and the Canadian Economic and Trade Office in China (ocean current note: specifically refers to Taiwan Province) also invited him to teach American and Canadian diplomats How to survive when buildings collapse.Chinese people grew up, during earthquake drills, the teacher always told the students to hide under the desks. After learning about this, Doug anxiously appealed again and again: don’t hide under the table or the bed, but use the table, The height of the bed is low, hiding next to the table and bed.
He explained the principle of not hiding under the table to avoid earthquakes with the earthquake escape video made in cooperation with the Turkish government and universities.
With the assistance of the Turkish government, the production unit blasted an abandoned building to simulate the collapse of the building during an earthquake. The staff first followed "common sense" and placed ten models next to furniture such as tables, beds, etc. After the explosives detonated, the building collapsed. He and the search and rescue team Yiyu found 20 mannequins. Of the 10 mannequins under the table and bed, eight of them were completely crushed, and one of them had its head, body, and feet broken into three pieces;
The ten models he placed were all safe and sound. He explained that when the ceiling of a building collapses due to a strong earthquake, furniture such as tables and beds will be crushed. If people hide in it, the consequences will be disastrous. Hide next to the furniture, the furniture can withstand the force of the collapsed objects, so that the people on the side can get living space.
Doug said that even if you encounter an earthquake while driving, you should get out of the car as soon as possible. Many people who died in the parking lot during the earthquake were crushed to death in the car, and the people between the two cars were not injured ( This paragraph quotes the picture description): When a strong earthquake occurs, if you are in the parking lot, do not stay in the car, lest the collapsed ceiling will crush the car and cause injury; you should hide beside the car in a prone position and fall The smallpox of the ceiling is pressed on the car, so as not to directly hit the person, which may form a "survival space" and increase the chance of survival.
He very seriously told the more than 100 Chinese (referring to Taiwan) search and rescue team members present that the search and rescue team members must first survive the earthquake and only survive in order to save the lives of others.He said that he hoped that everyone would tell everyone that as long as such a small amount of survival information is spread, the casualty rate in buildings can be reduced from 90% to 2% when an earthquake occurs.
2. Buildings.With the rapid development of social urbanization, more and more high-rise buildings have sprung up.Although the new high-rise buildings are designed and constructed according to the seismic intensity zoning made by the earthquake department, there are many unknown factors in the earthquake, and adequate preparations should be made before the earthquake to prevent unexpected events during the earthquake.If you live in an old building with fragile infrastructure, you must be prepared.If before the earthquake, based on the macroscopic abnormalities (such as abnormal cats, dogs, goldfish, birds and other animals kept at home, abnormally turbid tap water, sudden abnormal weather, etc.) and the official earthquake forecast, the best plan for active evacuation can be adopted.
3. If there are too many people, find a hiding place first.Schools, shops, movie theaters and other places where people gather should avoid panic in the event of an earthquake. They should immediately hide under desks, chairs or solid objects, and evacuate in an orderly manner after the earthquake.Evacuation measures in large public places: Do not panic and avoid running around, so as not to cause unnecessary casualties.
Teachers and other on-site staff must calmly direct people to avoid shocks on the spot, and must not take the lead in running around.If you are in a movie theater, gymnasium, etc., you can squat under the row of chairs on the spot, protect your head with a school bag, etc., and pay attention to avoid hanging objects such as chandeliers and electric fans.For example, the best way is to hide under the row of chairs when there is an earthquake in movie theaters and theaters.The general rows of chairs are screwed and connected by nine-ply board and cast iron frame. The compressive capacity of each nine-ply board is not strong, but the strength of the rows of chair backs is very great.General movie theaters and theaters all adopt long-span thin-shell structure roofs, which are light in weight, not easy to collapse during earthquakes, and the collapsed weight is not too large.In addition, the foot of the stage is also a good place to take refuge.
The anti-earthquake effect of civil air defense projects is excellent, which has been proved by the Tangshan and Baotou earthquakes.So as long as there is time, you can enter the civil air defense project or the basement.Because there are many similarities between the damage of earthquakes to urban buildings and the impact of nuclear explosions, the protection principles and methods are also very similar.
When you are in an underground shopping mall, you must obey the instructions of the on-site staff. Do not panic and crowd, and avoid crowds to prevent falling; and put your hands on your chest to protect yourself, and use your shoulders and back to withstand external pressure.When moving with the flow of people, avoid being squeezed into walls or fences; unbutton your collar to keep your breath open.You can also hide in counters and frames, squat in inner corners and pillars, and protect your head.
4. Stay away from the danger zone.If there is an earthquake on the street, you should cover your head with your hands, it is best to find an object to cover your head, and quickly stay away from buildings and go to the middle of the street.If you encounter an earthquake in the suburbs, pay attention to stay away from cliffs, steep slopes, river banks and high-tension lines.Pay attention to avoid tall buildings, especially tall buildings with glass walls, chimneys, water towers, billboards, street lights, large cranes, brick piles, cement prefabricated board walls, oil depots, dangerous goods warehouses, overpasses, overpasses, etc.Cars and trains in motion should stop immediately.When driving on a public streetcar or car, hold the handrail firmly and lower your head to avoid falling or bruising; you can lower your center of gravity and hide near the seat to prevent accidents.Wait for the car to stop and the earthquake to pass before getting off.Drivers should close the windows, do not lock the doors, leave the car keys in the car, and act together with other people in the car.
Those who were in the suburbs during the earthquake should quickly leave dangerous places such as mountains and water to prevent landslides, ground fissures, flooding and other emergencies.Those who ride bicycles get off, those who drive cars stop, and people walk aside.Listen to the radio for earthquake news and action guidelines.
5. To be buried, one must conserve energy.If you are unfortunately buried by ruins after the earthquake, try to keep calm and try to save yourself. You must try to move the movable objects around you, expand the space, and reinforce them to prevent aftershocks.Do not use an open flame at this time to prevent leakage and explosion of flammable gas.Cover your mouth and nose to prevent the leakage of poisonous gas nearby, and then look for opportunities to call for help and wait for rescue.When you cannot get out of danger, you should conserve your energy, try your best to find food and water, create living conditions, and wait patiently for the rescuers.
Cover your mouth, nose and head with a wet towel, clothing or other cloth as much as possible.
Move your hands and feet as much as possible to remove the dust on your face and objects pressed on your body.
Support the weight above your body with something you can move around.
Expand the activity space and keep enough air.
Find and open passages to move toward brighter, safer and more spacious places.
Use substitutes and water sparingly.
To save energy as much as possible, you can use bricks, iron pipes and other objects to knock on the wall to send a message to the outside world, and call for help when you are sure that there is someone not far away.
When several people are buried under pressure at the same time, they should encourage each other, plan together, cooperate in solidarity, and take action to escape danger when necessary.
[Zhang Xiaodong, deputy director of the China Seismic Network Center, made a speech on the aftershocks of the Wenchuan Earthquake]
After a major earthquake occurs, according to past experience, there are still types of earthquakes. Some earthquakes are large, but aftershocks are very small and very few. This is an isolated earthquake.Some earthquakes are rich in aftershocks.After the earthquake, there were many aftershocks, and we monitored many aftershocks.There were aftershocks just now.After the earthquake, many buildings were damaged and collapsed, and some buildings have not yet completely collapsed but have been damaged. When these buildings are hit by relatively strong aftershocks later, they will continue to be damaged, including rescuers and crushed people. Certain protective measures must be taken in the aftershocks. If there are no protective measures, the disaster may further expand.Therefore, the monitoring of aftershocks is also very important, and we must take certain measures before aftershocks occur.In addition, the traffic in that place is inconvenient, and it is easy to cause landslides. These aftershocks will further intensify the landslides, so dealing with aftershocks is still a very important issue.
I have been to international rescue sites before, and it is very important that these search and rescue personnel and local personnel participating in the rescue have this knowledge.Because aftershocks are happening one after another, dangerous buildings should not be approached. It is very important to have this knowledge.Second, search and rescue personnel must also have this knowledge, because they will work in the ruins, and aftershocks at this time may cause harm, so professionals must undergo training in this area to avoid further harm to people after aftershocks.
Bigger earthquakes have more _and larger aftershocks _and the sequences can last for years or even longer especially when a large event occurs in a seismically quiet area
The rate of aftershocks decreases quickly - the decrease is proportional to the inverse of time since the main shock. This means the second day has about 1/2 the number of aftershocks of the first day _and the tenth has about 1/10 the number of the first day.
How long this lasts depends on the size of the main shock (bigger earthquakes have more aftershocks) _and how active the region was before the main shock (if the region was seismically quiet before the main shock, the aftershocks continue above the previous rate for a longer time). Thus, an aftershock can occur weeks or decades after a main shock.
He explained the principle of not hiding under the table to avoid earthquakes with the earthquake escape video made in cooperation with the Turkish government and universities.
With the assistance of the Turkish government, the production unit blasted an abandoned building to simulate the collapse of the building during an earthquake. The staff first followed "common sense" and placed ten models next to furniture such as tables, beds, etc. After the explosives detonated, the building collapsed. He and the search and rescue team Yiyu found 20 mannequins. Of the 10 mannequins under the table and bed, eight of them were completely crushed, and one of them had its head, body, and feet broken into three pieces;
The ten models he placed were all safe and sound. He explained that when the ceiling of a building collapses due to a strong earthquake, furniture such as tables and beds will be crushed. If people hide in it, the consequences will be disastrous. Hide next to the furniture, the furniture can withstand the force of the collapsed objects, so that the people on the side can get living space.
Doug said that even if you encounter an earthquake while driving, you should get out of the car as soon as possible. Many people who died in the parking lot during the earthquake were crushed to death in the car, and the people between the two cars were not injured ( This paragraph quotes the picture description): When a strong earthquake occurs, if you are in the parking lot, do not stay in the car, lest the collapsed ceiling will crush the car and cause injury; you should hide beside the car in a prone position and fall The smallpox of the ceiling is pressed on the car, so as not to directly hit the person, which may form a "survival space" and increase the chance of survival.
He very seriously told the more than 100 Chinese (referring to Taiwan) search and rescue team members present that the search and rescue team members must first survive the earthquake and only survive in order to save the lives of others.He said that he hoped that everyone would tell everyone that as long as such a small amount of survival information is spread, the casualty rate in buildings can be reduced from 90% to 2% when an earthquake occurs.
2. Buildings.With the rapid development of social urbanization, more and more high-rise buildings have sprung up.Although the new high-rise buildings are designed and constructed according to the seismic intensity zoning made by the earthquake department, there are many unknown factors in the earthquake, and adequate preparations should be made before the earthquake to prevent unexpected events during the earthquake.If you live in an old building with fragile infrastructure, you must be prepared.If before the earthquake, based on the macroscopic abnormalities (such as abnormal cats, dogs, goldfish, birds and other animals kept at home, abnormally turbid tap water, sudden abnormal weather, etc.) and the official earthquake forecast, the best plan for active evacuation can be adopted.
3. If there are too many people, find a hiding place first.Schools, shops, movie theaters and other places where people gather should avoid panic in the event of an earthquake. They should immediately hide under desks, chairs or solid objects, and evacuate in an orderly manner after the earthquake.Evacuation measures in large public places: Do not panic and avoid running around, so as not to cause unnecessary casualties.
Teachers and other on-site staff must calmly direct people to avoid shocks on the spot, and must not take the lead in running around.If you are in a movie theater, gymnasium, etc., you can squat under the row of chairs on the spot, protect your head with a school bag, etc., and pay attention to avoid hanging objects such as chandeliers and electric fans.For example, the best way is to hide under the row of chairs when there is an earthquake in movie theaters and theaters.The general rows of chairs are screwed and connected by nine-ply board and cast iron frame. The compressive capacity of each nine-ply board is not strong, but the strength of the rows of chair backs is very great.General movie theaters and theaters all adopt long-span thin-shell structure roofs, which are light in weight, not easy to collapse during earthquakes, and the collapsed weight is not too large.In addition, the foot of the stage is also a good place to take refuge.
The anti-earthquake effect of civil air defense projects is excellent, which has been proved by the Tangshan and Baotou earthquakes.So as long as there is time, you can enter the civil air defense project or the basement.Because there are many similarities between the damage of earthquakes to urban buildings and the impact of nuclear explosions, the protection principles and methods are also very similar.
When you are in an underground shopping mall, you must obey the instructions of the on-site staff. Do not panic and crowd, and avoid crowds to prevent falling; and put your hands on your chest to protect yourself, and use your shoulders and back to withstand external pressure.When moving with the flow of people, avoid being squeezed into walls or fences; unbutton your collar to keep your breath open.You can also hide in counters and frames, squat in inner corners and pillars, and protect your head.
4. Stay away from the danger zone.If there is an earthquake on the street, you should cover your head with your hands, it is best to find an object to cover your head, and quickly stay away from buildings and go to the middle of the street.If you encounter an earthquake in the suburbs, pay attention to stay away from cliffs, steep slopes, river banks and high-tension lines.Pay attention to avoid tall buildings, especially tall buildings with glass walls, chimneys, water towers, billboards, street lights, large cranes, brick piles, cement prefabricated board walls, oil depots, dangerous goods warehouses, overpasses, overpasses, etc.Cars and trains in motion should stop immediately.When driving on a public streetcar or car, hold the handrail firmly and lower your head to avoid falling or bruising; you can lower your center of gravity and hide near the seat to prevent accidents.Wait for the car to stop and the earthquake to pass before getting off.Drivers should close the windows, do not lock the doors, leave the car keys in the car, and act together with other people in the car.
Those who were in the suburbs during the earthquake should quickly leave dangerous places such as mountains and water to prevent landslides, ground fissures, flooding and other emergencies.Those who ride bicycles get off, those who drive cars stop, and people walk aside.Listen to the radio for earthquake news and action guidelines.
5. To be buried, one must conserve energy.If you are unfortunately buried by ruins after the earthquake, try to keep calm and try to save yourself. You must try to move the movable objects around you, expand the space, and reinforce them to prevent aftershocks.Do not use an open flame at this time to prevent leakage and explosion of flammable gas.Cover your mouth and nose to prevent the leakage of poisonous gas nearby, and then look for opportunities to call for help and wait for rescue.When you cannot get out of danger, you should conserve your energy, try your best to find food and water, create living conditions, and wait patiently for the rescuers.
Cover your mouth, nose and head with a wet towel, clothing or other cloth as much as possible.
Move your hands and feet as much as possible to remove the dust on your face and objects pressed on your body.
Support the weight above your body with something you can move around.
Expand the activity space and keep enough air.
Find and open passages to move toward brighter, safer and more spacious places.
Use substitutes and water sparingly.
To save energy as much as possible, you can use bricks, iron pipes and other objects to knock on the wall to send a message to the outside world, and call for help when you are sure that there is someone not far away.
When several people are buried under pressure at the same time, they should encourage each other, plan together, cooperate in solidarity, and take action to escape danger when necessary.
[Zhang Xiaodong, deputy director of the China Seismic Network Center, made a speech on the aftershocks of the Wenchuan Earthquake]
After a major earthquake occurs, according to past experience, there are still types of earthquakes. Some earthquakes are large, but aftershocks are very small and very few. This is an isolated earthquake.Some earthquakes are rich in aftershocks.After the earthquake, there were many aftershocks, and we monitored many aftershocks.There were aftershocks just now.After the earthquake, many buildings were damaged and collapsed, and some buildings have not yet completely collapsed but have been damaged. When these buildings are hit by relatively strong aftershocks later, they will continue to be damaged, including rescuers and crushed people. Certain protective measures must be taken in the aftershocks. If there are no protective measures, the disaster may further expand.Therefore, the monitoring of aftershocks is also very important, and we must take certain measures before aftershocks occur.In addition, the traffic in that place is inconvenient, and it is easy to cause landslides. These aftershocks will further intensify the landslides, so dealing with aftershocks is still a very important issue.
I have been to international rescue sites before, and it is very important that these search and rescue personnel and local personnel participating in the rescue have this knowledge.Because aftershocks are happening one after another, dangerous buildings should not be approached. It is very important to have this knowledge.Second, search and rescue personnel must also have this knowledge, because they will work in the ruins, and aftershocks at this time may cause harm, so professionals must undergo training in this area to avoid further harm to people after aftershocks.
Bigger earthquakes have more _and larger aftershocks _and the sequences can last for years or even longer especially when a large event occurs in a seismically quiet area
The rate of aftershocks decreases quickly - the decrease is proportional to the inverse of time since the main shock. This means the second day has about 1/2 the number of aftershocks of the first day _and the tenth has about 1/10 the number of the first day.
How long this lasts depends on the size of the main shock (bigger earthquakes have more aftershocks) _and how active the region was before the main shock (if the region was seismically quiet before the main shock, the aftershocks continue above the previous rate for a longer time). Thus, an aftershock can occur weeks or decades after a main shock.