Natural disasters refer to natural phenomena that bring harm to human survival or damage to the human living environment, throughout history, the destructive power and influence of this natural disaster have a huge impact on human life for a very long time, such as the Tangshan University in 1976, which killed more than 240,000 people and seriously injured more than 160,000 people. With the passage of time, people have a deeper understanding of natural disasters, which has also become an important test point in the geography part of the public examination, for example, to examine the formation of natural disasters, the impact of natural disasters, measures to cope with natural disasters and escape, etc., today summarized the two natural disasters commonly tested in the public examination:
1. Heavy rain and flooding.
Heavy rains and floods in China mainly occur in summer and autumn, except for the western desert areas, there are heavy rains, and there are extremely heavy rains and heavy rains in the south and east. Whether it is the severe rainstorm disaster in Henan in 2021, which caused serious damage to transportation facilities such as the subway, or the severe rainstorm disaster in Guangdong in 2023, which allowed Shenzhen to break the record of the largest precipitation since meteorological records began, we can see the extent of the damage caused by heavy rainfall. The occurrence of heavy rain is mainly affected by atmospheric circulation, weather and climate systems, and is a natural phenomenon. But the factors that contribute to the serious consequences of heavy rains are manifold:
1. Natural factors: Weather and climatic factors are the direct causes of heavy rainfall. Due to their blocking effect, plateaus and mountains often form terrain and are prone to heavy rainfall. At the same time, secondary disasters such as landslides and debris flows are induced. Encountering high-intensity, large-scale rainstorms, especially persistent heavy rains, is prone to serious consequences.
According to China's meteorological regulations, the rainfall in 12 hours is 300～69.9 mm or 50 rainfall in 24 hours0～99.Heavy rain between 9 mm; 70 rainfall in 12 hours0～139.9 mm or 100 rainfall in 24 hours0～249.Heavy rain between 9 mm; 1400 mm or 250 rainfall in 24 hoursBetween 0 mm is extremely heavy rain. For example, Shenzhen's maximum cumulative rainfall in September was 4690 mm, known as a heavy rainstorm.
2. Human factors: indiscriminate logging, destruction of vegetation, and serious soil erosion; The water storage capacity of the lake decreases; Excessive groundwater pumping in large and medium-sized cities has caused land subsidence and exacerbated the danger of urban flooding.
In the event of a flood, how to avoid danger? Stay calm and follow commands; When you have no time to transfer or are trapped outside, do not panic, you can move to a higher place (such as a sturdy building roof, on a big tree) and wait for rescuers to rescue you; If the flood is severe and the water level is constant, you should be prepared for escape (plan your route in advance and use the floating objects around you).
2. The vibration caused by the rapid release of energy from the earth's crust is a natural phenomenon that will produce **waves during the period, which is called. On the earth, the plates and plates squeeze and collide with each other, resulting in the dislocation and rupture of the plate edge and the plate inside, which is the main reason for the cause, China is in one of the world's three major belts - the Pacific Rim belt, more frequent, according to our current understanding of the world, the early warning time is limited, how to correctly absorb the shock is very important, and it is also a very popular content in the general knowledge exam. First of all, we must distinguish a few concepts:
Hypocenter: The place where the rupture of the Earth's inner rock layers causes a vibration.
Epicenter: The point where the ground is directly opposite the hypocenter.
Magnitude: Magnitude, which is related to the amount of energy released. The magnitude standard currently used in China is the internationally accepted Richter scale, which is divided into 9 grades. Generally less than 2Level 5 ** person has no feeling, 2People above level 5 have feelings, and ** above level 5 will cause damage.
Severity: Indicates the degree of impact and damage to the ground at **.
Distinction: There is only one magnitude at a time, and there can be multiple intensities. Intensity is also closely related to the depth of the epicenter, the distance between the epicenter, the geological structure and the ground structure.
*How to save yourself and escape after the incident?
1. Indoor: If you are at home, you can choose to hide under the bed in the bedroom, under the bathroom or other sturdy furniture; If you're at school or in the office, you can hide under your desk or desk. When evading, cover your mouth and nose with a towel or clothing to prevent smoke and dust from being inhaled. Open the door to facilitate the escape and rescue after the first day; Turn off the power switch and gas valve to avoid secondary disasters caused by **, thereby reducing the difficulty of rescue; Do not take the elevator to escape, do not jump off the building to escape, wait for the strong earthquake to pass before evacuating quickly and orderly.
2. Outdoor: If we are in a relatively open place, squat in a safe place and do not move around at will; If we are at the bottom of the mountain, we should be careful to avoid the mountainside area, because there is a possibility of landslides and mudslides after **; If you encounter landslides and mudslides after **, you should quickly flee in the direction of movement perpendicular to the rolling stones.
Test Question Practice] (Multiple Choice)**Natural disasters such as typhoons often cause huge property damage and people**. The following statements about natural disasters are true:
a.Debris flows have the characteristics of suddenness, fast flow speed and strong destructive power, and generally occur in areas with special topography and landforms.
b.A typhoon is a tropical cyclone that occurs in the western Pacific Ocean and the South China Sea, and the wind strength in the eye of the typhoon is the basis for determining the typhoon level.
c.Volcanic eruptions are a form of energy released from within the earth, and volcanoes throughout the earth are distributed on land and are divided into extinct volcanoes, active volcanoes, and dormant volcanoes.
d.It mostly occurs at the junction of the earth's plates or in the crustal fissures, and the intensity is the degree of influence and damage to the ground, and the deeper the epicenter, the greater the intensity.
Answer] a. Analysis: Debris flow refers to a special torrent that carries a large amount of sediment and stones due to landslides caused by heavy rain, heavy snow or other natural disasters in mountainous areas or other ravines and areas with steep terrain. option a is correct; In option b, it is a tropical cyclone that occurs in the western Pacific Ocean and the South China Sea, but the typhoon wind strength is divided into six categories according to the maximum average wind speed near the center of the bottom of the typhoon: tropical depression, tropical storm, severe tropical storm, typhoon, severe typhoon, and super typhoon. The wind in the eye of the typhoon is very small, and the weather is sunny, so b is not selected; Volcanic eruptions are a form of energy release within the earth, but volcanoes on the earth are not only distributed on land, but also in the oceans, so C is not selected; For ** with the same magnitude, the shallower the source, the greater the intensity, and the greater the damage, so D is not selected.
The correct answer is A.
The knowledge points examined in this question are mainly the natural disasters in physical geography, which belongs to the content of the geography part. This kind of question is relatively comprehensive in public knowledge, and it requires a certain understanding of daily common sense problems, and this question is no exception. In recent years, regarding the common natural disasters in China, especially in the examination cycle, frequent natural disasters are more likely to appear in the exam, and candidates can pay more attention.