What are the signs before the earthquake? Thank you, everyone.

Before the earthquake, the phenomena related to earthquake preparation in nature are called earthquake precursors. In the long-term practice, the ancients in China have long recognized that earthquakes are precursors, and left rich records of earthquake precursors. For example, after the 1739 Yinchuan earthquake in Ningxia, it was inferred that there might be some relationship between the earthquake and well water changes, animal uneasiness, underground sound before the earthquake and abnormal weather phenomena. Six kinds of earthquake precursor phenomena summarized by the ancients are recorded in the ancient book Lund County Records. The in-depth study of modern earthquake science shows that there are indeed various precursor phenomena before earthquakes. Earthquake precursors are divided into macro precursors and micro precursors. 1. Macroscopic precursors of earthquakes can be directly perceived by human senses. The more common ones are the sudden rise and fall of well water, discoloration and odor, flowering and bubbling, temperature fluctuation, sudden change of spring water flow, sudden change of hot spring water temperature, abnormal animal habits, earth sound and earth light before the earthquake, etc. Macroscopic precursors play an important role in earthquake prediction. Before Liaoning 1975 Haicheng earthquake with M = 7.3 and 1976 Songpan-Pingwu earthquake with M = 7.2, seismologists and the general public had observed a large number of macroscopic anomalies, which provided important information for the successful prediction of these two earthquakes. However, we should also pay attention to the various macro phenomena listed above, which may be caused by various reasons, and are not necessarily signs of earthquakes. For example; The group fluctuation of well water and spring water may be related to rainfall, and may also be affected by nearby pumping, drainage and construction. The discoloration of well water may be caused by pollution, and the abnormal behavior of animals may be related to weather changes, diseases, estrus and external stimuli. Also be careful not to mistake welding arc light and lightning for earth light, thunder for earth sound, and fireworks and flares for underground fireballs. -once you find an abnormal natural phenomenon, don't easily draw the conclusion that an earthquake will happen soon, let alone panic. Instead, it is necessary to find out the time, place and relevant situation of abnormal phenomena, protect the site, report to the earthquake department or the government, and let the professionals in the earthquake department investigate and verify the truth. 2. The microscopic precursors of earthquakes can't be detected by human senses, and those that can only be measured by special instruments are called microscopic precursors of earthquakes, which mainly include the following categories: abnormal seismic activity. There is a certain relationship between large and small earthquakes. Although there are not many major earthquakes, there are many small and medium-sized earthquakes. Study the characteristics of moderate and small earthquakes. It is possible to help people predict the occurrence of future major earthquakes. Terrain anomaly. Before the earthquake, the crust near the epicenter may be slightly deformed, and the rocks on both sides of some faults may be slightly displaced. With the help of precision instruments, this very small change can be measured, and analyzing these data can help people predict the occurrence of future major earthquakes. Geophysical changes. In the process of earthquake preparation, some changes may occur in the physical properties of rocks in the source area and its surrounding areas. Using precision instruments to measure the changes of gravity, geoelectricity and geomagnetism in different areas can also help people predict earthquakes. Changes of underground fluid. Groundwater (well water, spring water, water contained underground), oil and natural gas and some other gases may be generated and stored in underground rock formations, which are all underground fluids. Measuring the chemical composition and some physical quantities of underground fluid with instruments and studying their changes can help people predict earthquakes. 3. In order to capture the microscopic precursors of earthquakes, it is necessary to establish an earthquake observation network covering an area for long-term accurate observation. An instrument for recording earthquakes is called a seismograph. Stations specializing in earthquake observation are called seismographs or seismographs. As early as 1800 years ago, Zhang Heng, a famous scientist in China, invented the world's first seismograph-"Houfeng seismograph". Modern seismographs adopt the most advanced electronic technology with high sensitivity, and there are even special submarine seismographs and deep well (borehole) seismographs. At present, a considerable number of seismic stations can automatically record seismic signals without special observation, and automatically transmit the signals to the receiving center through cables or radio waves, and then the signals are automatically processed by computers. This is the so-called telemetering seismic network. Modern telemetering seismic network has been established in many areas of China, including Sichuan Province. In addition, there are earthquake precursor observation stations such as geoelectricity, geomagnetism, gravity, topographic change and underground fluid. Before liberation, there was only one seismic station and three seismologists in old China, and the earthquake cause was extremely backward. After liberation, the earthquake cause in New China has made great progress. 1957. Chengdu Seismic Station, the first seismic station in Sichuan Province, was established in the western suburbs of Chengdu. 1966 After the Xingtai earthquake, with the cordial care of Premier Zhou Enlai, the earthquake cause in China accelerated. 197 1 year, the state seismological bureau (now seismological bureau of China) was established. After nearly 30 years of hard work, the earthquake observation network has begun to take shape. At present, more than I000 modern seismic stations (including local seismic stations) have been established in China, and seismic observation technology has been widely used. 1. The microscopic and macroscopic anomalies of the earthquake are relatively large. Various anomalies often occur before earthquakes, which has been confirmed by many earthquakes at home and abroad. All kinds of anomalies related to earthquakes are called earthquake anomalies, also known as earthquake precursors. Earthquake precursors can be divided into two categories, one is microscopic precursors and the other is macroscopic precursors. Micro-precursors refer to those abnormal phenomena that can only be observed by instruments, such as changes in the characteristics of small earthquakes, small deformation of the earth's crust, changes in the earth's gravity field, changes in the earth's magnetic field, changes in the earth's electric field and resistivity, changes in electromagnetic wave propagation, changes in groundwater dynamics and chemical composition, and so on. Seismologists use special instruments to observe and analyze microscopic precursors. Macroscopic precursors refer to abnormal phenomena that can be directly perceived by human senses, including small earthquake activities that people can feel. If people correctly and accurately judge macro-anomalies and take preventive measures in time, they will achieve remarkable disaster reduction effects. 2. The abnormal behavior of animals before the earthquake is one of the important macro-anomalies. It is observed that many animals will have abnormal reactions before a big earthquake. There are many such animals, including tigers, wolves, deer, pandas, monkeys, mice, eagles, swans, snakes, turtles, frogs, eels, ants and so on. Very sensitive to the coming earthquake. Horses, cows, donkeys, dogs, pigs, sheep, cats, rabbits, chickens, pigeons, bees, etc. Animals raised artificially also reacted before the earthquake. The night before the Tangshan earthquake, a rural child saw the mouse in the yard "moving" and was not afraid of people. He advised his mother to move out to sleep, saying that there might be an earthquake. As a result, an earthquake really happened a few hours later. Unfortunately, the mother didn't listen to the child's advice, and the clever child died in the earthquake. Before the Tangshan earthquake, a farmer's dog howled in the earthquake zone. The owner kicked the dog out of the door, and the dog forced the door open, barking even harder and even biting the owner. The owner was pestered by the dog until midnight. When the earthquake happened, the family ran out of the house in time because they were not asleep, and escaped the disaster. After the Tangshan earthquake, people noticed that rural farmers suffered the least casualties. None of the farmers in West Street 12 in Fengnan County who suffered the most were injured. The reason is that their livestock behaved abnormally before the earthquake. The breeder was busy raising them and was attracted to the outdoors, but they survived. There are many similar situations in other major earthquakes. 1975 Before the Haicheng earthquake of magnitude 7.3 in Liaoning Province on February 4, it was in the middle of winter, and hundreds of snakes were found to stop hibernating, climb out of caves and freeze in the snow. Some snakes have the first half frozen and the second half arched. Animals were abnormal before the earthquake because some of their sensory organs were particularly sensitive and could respond to small physical and chemical changes in nature before the earthquake. Scientists have found that pigeons have a small body in their legs and can feel tiny mechanical vibrations. There are more than 100 corpuscles, smaller than millet, connected by nerves. Vibration of a few tenths of a micron can make them emit nerve electricity. Scientists did an experiment to cut off the blood cell nerves of some domestic pigeons. Results Before the earthquake of magnitude 4 or above, most pigeons without corpuscles were scared to fly, while pigeons with corpuscles cut off were quiet as usual. 3. Before the earthquake, well water anomalies are also common macro anomalies, which are mainly manifested as abnormal fluctuation of water surface and frosting, foaming, discoloration and taste change of well water. 1970 65438+1On October 5th, an earthquake of magnitude 7.7 occurred in Tonghai, Yunnan. A few days before the earthquake, the taste of a sweet well in a village in the earthquake zone became salty and bitter. In another place, there is a well dedicated to making tofu. Before the earthquake, well water did not coagulate when making tofu, but it can make tofu again three days after the earthquake. Before the Tangshan earthquake, a 50-meter-deep well in Yangguan Village, Feng Run County smelled the small hole in the manhole cover. On July 25 and 26, steaming reached its climax, and the sound of steaming could be heard 20 meters away. A major earthquake occurred on the 28th, and the venting stopped several days after the earthquake. Abnormal changes in groundwater, such as well water before the earthquake, are due to abnormal extrusion of rock strata, changes in water pressure, or infiltration of substances that did not exist before. 4. Although the changes of the earth's light and sound are also macroscopic precursor phenomena, they are already the "ultimatum" issued by the earthquake because they are very close to the earthquake time. Before the Haicheng 1975M = 7.3 earthquake in Liaoning, more than 90 people saw the phenomenon of terrestrial light. Before 1976 Tangshan earthquake and Sichuan Songpan earthquake, many people saw the light of the earth and heard the voice of the earth. The ground light is flaky, banded, columnar and spherical; Colors are blue, red, white and so on. There are many kinds of ground sounds, some of which are "muffled thunder", some of which are like the whistling of the wind, such as the driving of heavy vehicles, or like the underground hordes of Ma Benteng. Before the Haicheng earthquake in Liaoning, the train from Dalian to Beijing was traveling in Haicheng, and a bright purple spark suddenly appeared in front of the driver. He realized that there was a situation and immediately braked urgently. Then an earthquake of magnitude 7.3 occurred, and the train avoided subversion in the extreme earthquake zone. 5. What should I do if I find something unusual? The phenomena in nature are very complicated, and macro anomalies should be carefully investigated and analyzed. First of all, we should distinguish between true anomalies and false anomalies. For this reason, we must accurately grasp the normal state. Secondly, it is necessary to analyze whether there are factors other than earthquakes that cause abnormalities. For example, abnormal animal behavior may be related to changing owners, changing environment, climate change, illness, and animal estrus. The change of well water may also be related to climate drought and flood and man-made water use; The acousto-optic phenomenon may also be the passing of heavy vehicles or the flash of electric welding. If any abnormality is found, it should be reported to the local government or earthquake management department immediately.