What are the phenomena of natural disasters?

"Natural disaster" is an abnormal phenomenon in the nature on which human beings depend, and the harm caused by natural disasters to human society is often shocking. Among them are earthquakes, volcanic eruptions, mudslides, tsunamis, typhoons, floods and other sudden disasters; There are also gradual disasters, such as land subsidence, land desertification, drought, coastline changes, etc., which can only gradually appear in a long time; There are also environmental disasters caused by human activities such as ozone layer change, water pollution, soil erosion and acid rain. There is a complex relationship between these natural disasters and environmental damage. It has become the common theme of the international community to scientifically understand the occurrence and development of these disasters and minimize their harm.

Natural variations on the earth, including those induced by human activities, occur all the time. When this mutation brings harm to human society, it constitutes a natural disaster. Because it has brought different degrees of damage to human production and life, including the relationship between man and nature through labor and the interpersonal relationship related to it. Disasters are negative or destructive. Therefore, natural disasters are a manifestation of the contradiction between man and nature, with the dual attributes of nature and society, and are one of the most severe challenges faced by mankind in the past, present and future.

The main sudden natural disasters in the world are: drought, flood, typhoon, storm surge, freezing injury, hail, tsunami, earthquake, volcano, landslide, debris flow, forest fire, agricultural and forestry diseases and insect pests, etc.

There are many kinds of natural disasters in China. Earthquake, typhoon, rainstorm, flood, waterlogging, high temperature, lightning, fog, haze, debris flow, landslide, tsunami, road icing, tornado, hail, snowstorm, collapse, land subsidence, sandstorm, etc. It occurs in all parts of the country and local areas every year, causing extensive damage or devastating blows in local areas.