When an earthquake occurs, the intensity of the earthquake in this area is affected by the distance from the epicenter and the magnitude. The higher the magnitude, the closer to the epicenter, and the stronger the earthquake. According to the information of focal center position, predicted intensity and early warning magnitude, the earthquake early warning system issues early warning notices of different earthquake sensitivity levels to the equipment in different distance areas from the epicenter. In areas where the earthquake is weak, you may only receive the notification bar message; Areas farther from the epicenter and hardly affected will not receive early warning notice.
It should be noted that in order to receive earthquake warning, the mobile phone needs to turn on positioning, maintain networking status, and turn on the earthquake warning function in the mobile phone settings. Not all types and models of mobile phones have earthquake warning function. When people turn on the earthquake early warning function, they can consult the relevant mobile phone manufacturers and turn it on under the guidance of the staff. If the phone doesn't have a built-in earthquake warning function, you can search for the keyword "earthquake warning" in the App store and download the related app yourself.
Earthquake precursor phenomenon
1, micro precursor
Before the earthquake, people's senses were not easy to detect, so they could only measure the changes with instruments. For example, the deformation of the ground, the change of the earth's magnetic field and gravity field, the change of the chemical composition of groundwater, the activity of small earthquakes, etc.
2. Macroscopic precursors
Earthquake precursors that can be perceived by human senses. Most of them are near the earthquake. Such as fluctuation and turbidity of well water, abnormal animal behavior, ground sound and ground light, etc.
3. Electromagnetic anomalies
Electromagnetic anomaly refers to the failure of household appliances such as radios, televisions and fluorescent lamps before the earthquake. The most common phenomena are radio failure, cell phone signal weakening or disappearing, and electronic alarm clock failure.