What are the precursors before the earthquake?

Precursors before the earthquake include: water anomaly, biological anomaly, meteorological anomaly, ground sound anomaly, ground light anomaly, ground gas anomaly, ground motion anomaly, ground heave anomaly and electromagnetic anomaly.

1, abnormal water

Groundwater includes well water, spring water, etc. The main anomalies are turbidity, bubbling, flowering, temperature rise, discoloration, off-flavor, sudden rise, sudden drop, sudden exhaustion or gushing.

2. Biological abnormality

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.

3. Meteorological anomalies

Before the earthquake, the weather often appeared abnormal. There are mainly sultry before the earthquake, anxiety and irritability, long drought or continuous rain, yellow fog scattered, dark sunshine, strange wind raging, hail (flying snow) in June and so on.

4. Abnormal ground sound

Geosound anomaly refers to the sound emitted underground before the earthquake. It sounds like cannon and thunder, as well as heavy cars and strong winds.

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.

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, which is scientifically called foreshock. The definition of foreshock is that all vibrations before the maximum magnitude are called foreshocks.

8. Abnormal grounding drum

The ground uplift anomaly refers to the uplift on the ground before the earthquake.

9. Electromagnetic anomalies

Electromagnetic anomalies refer to the anomalies of household appliances such as radios, televisions and fluorescent lamps before the earthquake.

Extended data:

The place where the earthquake started is called the source, and the ground directly above the source is called the epicenter. The strongest ground motion of a destructive earthquake is called the extreme earthquake zone, which is often the area where the epicenter is located. Earthquakes often cause serious casualties, which can cause fires, floods, toxic gas leakage, the spread of bacteria and radioactive substances, and may also cause secondary disasters such as tsunami, landslides, collapses and ground fissures.

According to statistics, there are about 5 million earthquakes on the earth every year, that is, tens of thousands of earthquakes occur every day. Most of them are too small or too far away to be felt; There are about a dozen or twenty earthquakes that can really cause serious harm to human beings; About one or two earthquakes will cause particularly serious disasters.

Earthquakes that people can't feel must be recorded by seismographs; Different types of seismographs can record earthquakes with different intensities and distances. Thousands of various seismic instruments are running around the world, monitoring the trend of earthquakes day and night.

References:

Baidu encyclopedia-earthquake precursors