Why was the earthquake not predicted?

Those who say they can't predict always confuse the audience with an accurate prediction before speaking. The current weather forecast cannot be accurately predicted.

Tangshan is only115km away from Tangshan, where 46W people in Qinglong County, Hebei Province did not die. You can find them online.

The 30th anniversary monument of Haicheng earthquake prediction was unveiled.

Anshan Daily News (Chief reporter Meng Tie) On the morning of 20th, the State Seismological Bureau and the provincial government held the unveiling ceremony of the 30th anniversary monument of successful earthquake prediction in Haicheng. Director of the State Seismological Bureau, Governor Zhang, Vice Governor, city leaders, Zhang Jiehui, Sun Chunshan and Li Shikai, secretary general of the municipal government Liu Shengxi, and leaders, experts and scholars from all provinces and cities in China who came to attend the 30th anniversary of Haicheng earthquake and academic seminar attended the unveiling ceremony. The unveiling ceremony was presided over by Mayor Zhang Jiehui.

Under the action of in-situ stress, in the process of stress and strain gradually accumulating and strengthening, rock mass will cause a series of abnormal changes in physics, chemistry, biology and meteorology of the source and nearby materials. We call these abnormal changes related to earthquake preparation and occurrence as earthquake precursors (also called earthquake anomalies). It includes microscopic earthquake anomalies and macroscopic earthquake anomalies.

Macroscopic anomaly of (1) earthquake

Earthquake anomalies that can be directly perceived by human senses are called earthquake macroscopic anomalies. The manifestations of earthquake macro-anomalies are diverse and complex, with hundreds of kinds of anomalies and thousands of anomalies, which can be roughly divided into groundwater anomalies, biological anomalies, geoacoustic anomalies, geooptical anomalies, electromagnetic anomalies, meteorological anomalies and so on.

1, groundwater anomaly

Groundwater includes well water, spring water, etc. The main anomalies are turbidity, bubbling, flowering, temperature rise, discoloration, odor change, sudden rise, sudden drop, borehole deformation, sudden exhaustion or spewing of spring water, etc. People summed up the proverbs of well water changes before the earthquake:

Well water is a treasure, and earthquakes have precursors.

When it doesn't rain, the spring water is turbid, and when it dries, well water emerges.

The water level rises and falls, and flowers are bubbling.

Some change color, some change taste.

2. Biological abnormality

Some organs of many animals are particularly sensitive. They can know some disasters ahead of humans, such as jellyfish in the ocean can predict storms, mice can avoid mine disasters or harmful gases in advance, and so on. As for the organs of vision, hearing, touch, vibration and balance, which plays the main role and which plays the role of assisting judgment may be different for different animals. Physical and chemical changes (vibration, electricity, magnetism, meteorology, abnormal radon content in water, etc.). ) The accompanying earthquake can often stimulate some sensory organs of some animals and cause abnormal reactions. If the gravity of an area changes, some animals may be able to feel it through its balance organs; Some animals' hearing organs may be able to detect abnormal vibrations. Before the earthquake, the underground strata have been moving slowly day by day, showing a creeping state, and there is strong friction between fault planes, so some people think that there will be low-frequency sound waves on the friction fault planes, only a few to ten times per second, which is lower than human hearing. People need more than 20 sound waves per second to feel it, but animals don't. Very sensitive animals will be frightened when they feel this sound wave, resulting in abnormal phenomena such as winter snakes coming out of holes, fish jumping out of the water, pigs and cows jumping in circles, dogs barking and wolves growling. There are many kinds of animal anomalies, including large livestock, poultry, cave animals, hibernating animals, fish and so on. The abnormal situation of animals, people also have a few words to sum up well:

Animals have signs before earthquakes, so it is very important to prevent and treat them by groups.

Cattle, sheep, mules and horses don't enter the stables, and pigs don't eat dogs and bite people.

Ducks don't go into the water and make noise on the shore, but chickens fly up the tree and scream loudly.

The snake came out of the hole in the ice and snow, and the mouse ran with the mouse in its mouth.

The rabbit jumped and bumped, and the fish jumped into the water.

Bees are moving noisily, but pigeons are too scared to fly back to their nests.

Every household observes and reports any abnormality.

In addition, some plants also had abnormal reactions before the earthquake, such as germination, flowering, fruiting or large-scale withering, abnormal exuberance and so on.

3. Meteorological anomalies

People often describe earthquake prediction scientists and technicians as "managing the sky, the ground and the hollow", which is indeed reasonable. Before the earthquake, the weather often appeared abnormal. There are mainly sultry before the earthquake, anxiety and irritability, long drought without rain or heavy rain, yellow fog, dark sunshine, strange wind, hail in June and so on.

4. Abnormal ground sound

Geosound anomaly refers to the sound emitted underground before the earthquake. Its sound is as changeable as cannon and thunder, like the driving of heavy vehicles and the surge of strong winds. When an earthquake occurs, longitudinal waves radiate from the source and propagate along the ground, making the air vibrate and sound. Because of the high speed but weak potential of longitudinal wave, people only smell its sound, but don't feel it unconsciously until the arrival of shear wave. Therefore, there is often a record in the epicenter that "before every earthquake, the underground sound expands like gas, like boiling water in a tripod". If you are in the epicenter, you can often hear the sound of a magnitude 3 earthquake. Geosound is the result of the structure and structure of underground rocks and the movement of liquid and gas contained in them, and a considerable part of it is a sign of impending earthquake. Mastering the knowledge of geosound may have a good effect on earthquake prediction and prevention.

5, abnormal grounding light

Geophysical anomalies refer to the light emitted underground before the earthquake, which has various colors, such as silver blue, white purple, etc., which are rare in daily life, but mainly red and white; Its forms are also different, such as ribbon, sphere, column, diffusion and so on. Generally speaking, the earth's light appears in a wide range, mostly within a few hours to a few minutes before the earthquake and lasts for a few seconds. In China, colorful luminous phenomena appeared during and before the Haicheng, Longling, Tangshan and Songpan earthquakes. Terrestrial light is often accompanied by natural phenomena such as earthquakes, landslides, landslides, collapses, sand blasting, water spraying and air jetting, and often moves regularly along a fault zone or an area, and is synchronized with other macro and micro anomalies, and its causes are always closely related to crustal movement. And controlled by geological conditions and the state of the surface and atmosphere, it can cause different degrees of harm to people, animals and plants.

At present, all the geomagnetic anomaly reports we have are from a few seconds before the earthquake to 1 minute. Such as Haicheng earthquake, Lancang earthquake and Gengma earthquake, similar reports have been collected.

6. Abnormal ground gas

Geo-atmospheric anomaly refers to the fog generated underground before the earthquake, also known as geo-aerosol or geo-fog. This kind of fog, with white, black and yellow colors, sometimes colorless, often appears in the days to minutes before the earthquake, often accompanied by strange smell, sometimes accompanied by noise or high temperature.

7. Abnormal ground movement

Abnormal ground motion refers to the ground shaking before the earthquake. It is a well-known phenomenon that the ground vibrates violently during an earthquake. But before the earthquake, sometimes I feel the ground shaking. This kind of shaking is different from an earthquake, and it swings very slowly. Seismographs often can't record it, but many people can feel it. The most obvious ground motion anomaly occurred before the Haicheng earthquake of magnitude 7.3 on February 4th, 1975. From the end of February to the end of June, there were 65438+ anomalies in Dandong, Kuandian, Fengcheng, Shenyang and Xiuyan.

8. Abnormal grounding drum

The ground uplift anomaly refers to the uplift on the ground before the earthquake. 1973 About half a year before the magnitude 7.9 earthquake in Luhuo, Sichuan, a drum appeared on a lawn in Tuoba District, Ganzi County. It was shaped like an inverted iron pot, about 20 cm high, and cracks appeared intermittently around it. The swelling disappeared after a few days, and it was repeated many times until the earthquake occurred.

Anomalies similar to ground heave include ground fissures and subsidence.

9. Electromagnetic anomalies

Electromagnetic anomalies refer to the anomalies of household appliances such as radios, televisions and fluorescent lamps before the earthquake. The most common electromagnetic anomaly is radio failure, and fluorescent lamps were also common before the North China earthquake. 1a few days before the Tangshan earthquake of magnitude 7.8 on July 28, 976, many radios in Tangshan and its surrounding areas broke down, with loud and small sounds, inaccurate frequency modulation and sometimes continuous noise. Also before the Tangshan earthquake, some people in the city saw fluorescent lamps turn red first and then light up at night. Some people in Beijing turn off the fluorescent lamp before going to bed, but the light is still on.

Electromagnetic anomalies also include abnormal operation of some motor equipment, such as abnormal microwave stations, interference from wireless power plants, and failure of electronic alarm clocks.

Macroscopic anomalies of earthquakes play an important role in earthquake prediction, especially in short-term and imminent prediction. Before the 1975 Haicheng M = 7.3 earthquake and the 1976 Songpan and Pingwu M = 7.2 earthquakes, 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, it should also be noted that the above macro phenomena may be caused by various reasons, not all of which are signs of earthquakes. For example, the 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 is about to happen, 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 government or the earthquake department, and let the professionals in the earthquake department investigate and verify to find out the truth.

(2) Microscopic anomalies of earthquakes

The seismic anomalies that can't be detected by human senses and can only be measured by special instruments are called microscopic anomalies 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.

Abnormal topographic changes: 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 weak change can be detected, 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 around the source area. Using precision instruments to measure the changes of gravity, geoelectricity and geomagnetism in different areas can also help people predict earthquakes.

Changes of underground fluids: Groundwater (well water, spring water, water contained in underground rock formations), oil and natural gas, and other gases may be generated and stored in underground rock formations, all of which are underground fluids. Using instruments to measure the chemical composition and some physical quantities of underground fluid and study their changes can help people predict earthquakes.