Natural disasters refer to phenomena such as casualties, property losses, social instability, and resource destruction caused by abnormal natural changes or a series of events. Its formation must have two conditions: First, there must be natural mutations as incentives, and second, there must be people, property, and resources that have been damaged as objects to withstand disasters.

Formation and development: All kinds of events that endanger animals and plants are called disasters. Looking at the history of mankind, we can see that there are two main causes of disasters: one is natural variation and the Other is human influence. Therefore, the disasters that are mainly caused by natural variations are often called natural disasters such as earthquakes, storms, and tsunami; the human-caused disasters are called man-made disasters such as man-induced fires, traffic accidents, and acid rain.

The process of the formation of natural disasters is long, short, and short. Some natural disasters, when the change in the hazards exceeds a certain intensity, will behave as disasters in days, hours, or even minutes or seconds, like volcanic eruptions, earthquakes, floods, hurricanes, storm surges, hailstorms. Snow disasters, storms, etc. These kinds of disasters are called sudden natural disasters. Droughts, crops, and forest diseases, insects, and weeds, although generally occurring within a few months, the formation and end of disasters are still relatively rapid and obvious, so they are also included in sudden natural disasters. . In addition, there are some natural disasters that gradually develop into disasters in the long-term development of disaster-causing factors such as land desertification, soil erosion, and environmental degradation. These types of disasters usually take several years or more to develop. It is a delayed natural disaster.

Many natural disasters, especially high-level and high-intensity natural disasters, often induce a series of other disasters. This phenomenon is called the disaster chain. The earliest occurring disasters in the disaster chain are called primary disasters; those induced by primary disasters are called secondary disasters. After a natural disaster took place, it destroyed the harmonious conditions for human survival. This can also lead to a series of other disasters. These disasters are generally called derivative disasters. After the drought, extreme depletion of surface and shallow fresh water forced people to drink deeper groundwater with high levels of fluoride, which led to fluorosis. These are called derivative disasters.

Of course, the process of disasters is often complicated. Sometimes a disaster can be caused by several kinds of disasters, or a disaster can cause several different types of disasters at the same time. At this time, the type of disaster is determined according to the leading cause of disaster and its main form of expression. This article was first published by China Rescue Equipment Network.