Some disasters can be avoided. Right?

Disaster is the general name of things that can have a destructive impact on human beings and the environment on which human beings depend. Disaster does not refer to the degree, but usually refers to the part, which can expand and develop into a disaster. For example, the phenomenon of locust pests is widespread in the biological world. When locusts multiply and spread in large areas, destroying crops and causing famine, it becomes a locust plague. The widespread spread and prevalence of infectious diseases and computer viruses will lead to disasters.

Disaster classification, according to the causes of man-made disasters or natural disasters; According to the cause, location and mechanism, there are geological disasters, weather disasters and environmental disasters, biochemical disasters and marine disasters.

Fire:

Fire refers to the burning phenomenon that time and space are out of control, causing property and personal injury. According to the fire losses (casualties, victims and direct property losses), it can be divided into general fires, major fires and extraordinarily serious fires.

China's fire rating is:

Extraordinary fire: refers to the fire that caused more than 10 people or seriously injured more than 20 people, killed or seriously injured more than 20 people, affected more than 50 households, and caused direct economic losses of more than10 million yuan;

Major fire: refers to the fire that killed or seriously injured more than 3 people 10, killed or seriously injured more than 10, affected more than 30 households, and caused direct economic losses of more than 300,000 yuan;

Those who do not have the above two situations are general fires.

Earthquake:

Earthquake is one of the major natural disasters on the earth. Earthquakes occur every day on the earth, most of which are small in magnitude or occur in remote areas such as the seabed, and people can't feel them. However, strong earthquakes in human activity areas often cause huge property losses and casualties.

The seismic wave produced by the earthquake can directly cause the destruction or even collapse of buildings; Destroy the ground, resulting in ground cracks, collapse, etc. ; Occurring in mountainous areas may also cause landslides, avalanches and so on. A strong earthquake on the seabed may trigger a tsunami. Aftershocks will make the damage more serious. The secondary disasters caused by earthquake mainly include building collapse, landslide, fire, flood and toxic gas leakage caused by pipeline rupture. In addition, when the bodies of casualties are not cleaned up in time, or drinking water is polluted by pollutants, it may lead to the outbreak of infectious diseases. In some earthquakes, the casualties and property losses caused by these secondary disasters may exceed the direct losses caused by earthquakes.

Earthquake prediction

For a long time, human beings have been trying to predict earthquakes in order to make preparations before earthquakes and reduce the losses of earthquake disasters. As early as the Eastern Han Dynasty, Zhang Heng invented the seismograph and recorded the Longxi earthquake in 138. It is generally believed that scientific earthquake prediction should make more accurate judgments on the time, place and magnitude of earthquakes. However, due to the complexity of the earth's internal activities and the lack of effective monitoring methods and prediction models, so far, human beings rarely make scientific predictions of earthquakes. Earthquake prediction is still a difficult problem in the world science today. At present, a relatively extensive earthquake monitoring network has been established around the world, and scientists have also obtained more information about the interior of the earth through ultra-deep drilling and other means. However, the level of human earthquake prediction is limited to making a rough medium-and long-term prediction of earthquake activity through the study of historical earthquake activity. In the short-term and imminent earthquake prediction, we mainly rely on the traditional observation and monitoring of earthquake precursors.

The first successfully predicted earthquake in the world was1February 4, 975, which occurred in Haicheng, Liaoning, China, with a magnitude of 7.3.

Earthquake precursor phenomenon

Earthquake precursors are all kinds of abnormal phenomena before earthquakes, especially large earthquakes. Divided into macro precursors and micro precursors. The former can be directly perceived by human sensory organs, such as the anomalies of animals and plants, groundwater, ground light and ground sound. The latter can not be directly detected by human sensory organs, but can be detected by professional instruments, such as topographic changes, geomagnetic field, gravity field, geothermal and geostress anomalies. Observation and monitoring of earthquake precursors is an important means of short-term earthquake prediction.

Earthquake protection

When an earthquake happens, the key is to keep a clear head, and correct protection is very important to ensure life safety and reduce casualties. A recent earthquake, which is usually relatively strong, may cause danger. Recent earthquakes often start with bumps, and the vibration is obvious, so we should escape quickly. Escape should follow the principle of avoiding nearby and pay attention to protecting your head.

You can temporarily hide under solid indoor furniture or in corners, kitchens, bathrooms and other places with more load-bearing walls and smaller spans, and pay attention to avoiding weak parts such as external walls. After the main earthquake, evacuate to the outside quickly. Outside, you can run to a relatively open and empty place to hide. If you want to pay attention to landslides and rolling stones in mountainous areas, you can find a higher place to hide. People buried under the rubble in the earthquake should try their best to escape if the environment and physical strength permit. If you are unable to escape from danger and save yourself, you should try to reduce your physical exertion and wait for rescuers.

Flood:

Flood, flood or flood is a natural disaster, which generally refers to the loss of people, property and buildings caused by excessive natural precipitation or untimely drainage.

Wind disaster: typhoon, tornado, hurricane;

typhoon

This is a tropical cyclone. Meteorologically, typhoon refers to a tropical cyclone that occurs in the western part of the North Pacific Ocean (west of the international international date line, including the South China Sea), and the central sustained wind speed reaches 12 or above (that is, more than 32.6 meters per second). As for tropical cyclones that occur in the Atlantic Ocean or the eastern North Pacific Ocean and reach the same intensity, they are called hurricanes. Traditionally, typhoons have also been used to collectively refer to all tropical cyclones that occur in the northwest Pacific. (Unless otherwise specified, the following "typhoon" adopts the second definition, which generally refers to all tropical cyclones in the northwest Pacific. )

From 1897 to 1996, the number and months of typhoons in the western Pacific Ocean and the South China Sea of China were counted. On average, 24 typhoons are generated every year, with the most typhoons occurring in August, followed by September and July.

tornado

It is a rather violent weather phenomenon, which is formed by the vertical hollow tube caused by the rapid rotation of clouds. This phenomenon appears in the global storm, and the "tornado alley" is the most famous in the vast areas of the midwest and south of the United States. Although the United States suffers more tornadoes than any other country, Britain suffers the most tornadoes in the world if the relevant land area is included.

outfall

Tornadoes are not confused with other meteorological eddies, such as dust rolls, which usually do not come from thunderstorms, but are completely different natural phenomena. According to the frequently asked questions about tornadoes from the National Weather Service, tornadoes are tornadoes on water-usually non-supercell tornadoes on water. Tornadoes usually occur along the southeast coast of the United States, especially in southern Florida and reefs (in the Gulf of Mexico), and oceans, bays and lakes all over the world may appear. Although a tornado is often defined as a tornado, in fact, in a formal definition, it cannot be classified as a tornado unless it attacks the land. Their destructiveness is smaller and weaker than that of the most powerful prairie, but they are still quite dangerous. Tornadoes can overturn ships and destroy them. When they land, they will do more damage and take lives. When tornadoes may occur or are already visible in coastal waters, the National Weather Service usually issues special warnings at sea, or issues tornado warnings when tornadoes will move to land.

Tornado common sense and safety

According to the data of Environment Canada, the probability of being directly overturned by a tornado is 1 20,000:1. Some people may change the year or region, but the actual possibility is low. Tornadoes do cause millions of dollars in economic and material losses, unemployment and casualties every year.

Every year at the beginning of the tornado season, schools and media circles in tornado areas spend time telling the public about the dangers and educating them on how to improve the survival rate in tornadoes. In America, people are often advised to buy NOAA weather radios. They are relatively cheap, costing only $20 now, and they will be warned of dangerous weather by the National Weather Service. The alarm was broadcast on both radio and TV. Most societies have civil defense alarms, which will be activated before they think a tornado is coming.

After the tornado warning was issued, all citizens were told to go to the refuge area. In most buildings, if possible, it is suggested to find a room with no window in the center or a corridor below the ground. If a tornado hits a building, it will cause a lot of debris to fall and hit people hiding indoors. Therefore, it is recommended to squat under the beam at the solid door or hide under the solid door furniture. However, when a tornado comes, light buildings such as mobile homes may be seriously damaged. Residents living in such houses will be told to evacuate their homes before the arrival of the tornado and look for stronger shelters, whether they go to designated shelters or the homes of nearby friends. In some areas, the storm cellar is also a refuge for people.

When a tornado strikes, the situation of vehicles is extremely dangerous. If the tornado is visible in the distance and the current traffic is smooth, you can move at right angles to the straight line of the tornado path to stay away from the tornado path. Otherwise, please park your car safely outside the traffic line as soon as possible (even if you find your car out of the soil afterwards, it is better than leaving it on the road and causing an accident). ), and look for solid buildings or trenches as shelters. Remember: under no circumstances should you stay in the car when a tornado comes. Under the strong wind force caused by tornado, any vehicle is very easy to be rolled up and thrown out.

Some people choose to take refuge under the continental bridge in the storm, but those places are not the best places to take refuge. The National Weather Service in Normandy, Oklahoma once made a report on the use of land bridges as cover in the tornado attack in Oklahoma on May 3, 1999. At that time, there were three land bridges on the tornado route in Oklahoma City, and at least one person died under each bridge. Land bridges have various architectural forms, and many of them will not provide any strong protection against strong winds and flying debris. In addition, the traffic jam caused by people parking their vehicles under or beside the bridge is likely to hinder the driving of other vehicles, thus indirectly depriving the latecomers of the opportunity to escape safely.

hurricane

Traditionally, it is a general term for tropical cyclones in the Atlantic Ocean and the eastern North Pacific Ocean.

Meteorologically, it refers to tropical cyclones in the Atlantic Ocean and the eastern North Pacific Ocean, with continuous winds of 63 knots/1 17 kilometers per hour.

In meteorology and navigation, the name of the twelfth wind in Beaufort scale; The wind force is greater than 63 nautical miles per hour/1 17 kilometers.

The old name of the ancient typhoon in China.

Volcanic eruption:

Volcanic eruption will do harm to human beings, but it also brings many benefits. Many gems are formed by volcanic eruptions; Volcanic eruption can also expand the land area, and the Hawaiian Islands were formed by volcanic eruption.

Scientific discoveries now show that there are volcanoes on many planets and satellites. There is also volcanic activity in the solar system, which is Io, the satellite of the Earth and Jupiter. On average, there are about 50 volcanic activities on earth every year. But most of them are at the bottom of the sea, in inaccessible mountainous areas, so there are few volcanic activities that have an impact on human beings.

Tsunami:

Tsunami is a powerful and destructive wave. When there is an earthquake on the seabed, the sea water fluctuates violently due to the power of seismic waves, forming powerful waves, moving forward and flooding the coastal areas one by one. This is the so-called tsunami.

Tsunami is called tsunami in many western languages, and the word comes from the Japanese word "tsunami", that is, "waves by the harbor" ("Tianjin" means "harbor"). This also shows that Japan is a country that is often hit by tsunamis. At present, human beings can only prevent or reduce the losses caused by sudden disasters such as earthquakes, volcanoes and tsunamis through observation and prediction, but they can't stop them from happening.

Tsunamis are usually caused by undersea earthquakes, with a focal point less than 50 kilometers below the seabed and a magnitude of 6.5 on the Richter scale. The wavelength of the tsunami is greater than the maximum depth of the ocean, and its spread near the seabed will not be greatly hindered. No matter how deep the ocean is, waves can pass through. The propagation speed of tsunami in the ocean is about 500 to 1000 kilometers per hour, and the distance between two adjacent waves may be as far as 500 to 650 kilometers. When the tsunami wave enters the continental shelf, the wave height suddenly increases because of its shallowness, and the wave height rolled up by this wave movement can reach tens of meters. The waves caused by earthquakes are different from those on the sea. Generally, waves only fluctuate in a certain depth of water layer, while the water body fluctuation caused by earthquake is the fluctuation from the sea surface to the whole water layer on the seabed. In addition, submarine volcanic eruptions, landslides and artificial underwater nuclear explosions can also trigger tsunamis. In addition, the meteorite impact will also trigger a tsunami, and the "water wall" can reach 100 feet. Moreover, the tsunami caused by meteorites can occur in any water area, not necessarily in the earthquake zone. However, the tsunami caused by meteorites may only happen once in a thousand years.