The geographical characteristics of landslide prone areas are rich in precipitation and large intera

This can also be said to be one of the causes of the landslide, but it is not a sufficient condition. Typically, the main causes of landslides are:

First, geological conditions and geomorphological conditions; The second is the influence of internal and external forces (power) and human effects. The first condition is related to the following:

1) Rock and soil type: Rock and soil are the material basis for landslides. Generally speaking, all kinds of rocks and soils may constitute landslide bodies, among which the rocks and soils with loose structure, low shear strength and weathering resistance, and their properties can change under the action of water, such as loose overburden, loess, red clay, shale, mudstone, coal measure strata, tuff, schist, slate, phyllite, etc., and the slope composed of soft and hard rock layers is prone to landslides.

2) Geological tectonic conditions: the conditions that make up the rock and soil of the slope can only slide downward when they are cut and separated into a discontinuous state by various structural planes. At the same time, the tectonic plane provides a channel for water currents such as rainfall to enter the slope. Therefore, all kinds of joints, cracks and landslides.

Landslides are most likely to occur when the slopes with gaps, planes and faults are developed, especially when the structural planes of parallel and vertical slopes with steep dipping angles and the structural planes with gentle slopes along the slope are developed.

3) Topography and geomorphological conditions: landslides can only occur if they are in a certain landform position and have a slope with a certain slope. Generally, the slopes of rivers, rivers, lakes (reservoirs), seas and ditches, the slopes of open mountains at the front edge, the slopes of railways, highways and engineering buildings are all landform parts that are prone to landslides.

The slope is more than 10 degrees, less than 45 degrees, the slope shape is steep in the middle and gently in the middle, and the upper part is in a ring shape, which is a favorable terrain for landslides.

4) Hydrogeological conditions: groundwater activity plays a major role in the formation of landslides. Its role is mainly manifested in:

Soften the rock and soil, reduce the strength of the rock and soil, produce hydrodynamic pressure and pore water pressure, latent erosion of rock and soil, increase the bulk density of rock and soil, and produce buoyancy on permeable rock formations. In particular, the softening effect on the slippery surface (belt) and reducing the strength are the most prominent. As far as the second condition is concerned, in the areas where the earth's crust moves and the areas with frequent human engineering activities are landslide-prone areas, external factors and actions can change the basic conditions for landslides, thereby inducing landslides.

The main inducing factors are: precipitation and snowmelt, surface water scouring, soaking, continuous erosion of the slope foot by surface water bodies such as rivers; Unreasonable human engineering activities, such as excavation of the foot of the slope, loading on the upper part of the slope, blasting, reservoir storage (discharge), mining, etc., can induce landslides, as well as such as tsunamis, storm surge, freeze-thaw and other effects can also induce landslides.

This is not necessarily, although some areas have abundant precipitation, but the vegetation coverage is very high, so there will be no mudslides. And all this has no necessary relationship with inter-annual changes...

Wrong. Landslides are not only related to precipitation, but also to soil quality and vegetation coverage.

The terrain is steep, the geology is loose, rainfall is abundant, and vegetation is scarce.

Summary. <>

There are many landslides and debris flows in the southwest of the country, due to the active crust, concentrated heavy rains in summer, serious damage to the surface vegetation caused by indiscriminate deforestation, and some other factors lead to landslides and frequent debris flows.

1) The mountainous areas of China are vast, and landslides and debris flows are widely distributed and occur frequently, especially in the southwest region. Analyze the causes of multiple occurrences.

There are many landslides and debris flows in the southwest of the country, due to the active crust, concentrated heavy rains in summer, serious damage to the surface vegetation caused by indiscriminate deforestation, and some other factors lead to landslides and frequent debris flows.

Thank you for your patience <>, the above are "1) China's mountainous areas are vast, landslides and debris flows are widely distributed and occur frequently, especially in the southwest region. Analyze the causes of multiple occurrences", you refer to whether there is any unclear place to continue to consult. <>

Test question analysis: Southwest China is located at the junction of the Eurasian plate and the Indian Ocean plate, with active crustal movement and obvious rock faults, which are prone to landslides. The climate of this region has distinct dry and wet seasons, strong weathering in dry season, more detrital material in mountainous areas, more heavy rain in summer and autumn, strong flow of water, and easy to form debris flow.

The phenomenon of indiscriminate felling in mountainous areas is serious, and the slope fixation effect of plants is poor, which aggravates the probability of landslides and debris flows. There is little volcanic activity in this region, and internal forces are the main reasons for frequent landslides and debris flows.

<> test center: The main reasons for the frequent occurrence of landslides and debris flows in southwest ChinaComments: This question is of average difficulty and is a competency question, which mainly tests students' cognitive and analytical ability of the causes of landslides and debris flows in southwest China.

What are the measures to prevent them?

Debris flow prevention and control measures: avoidance measures in the debris flow development and distribution area, industrial and mining, villages and towns, railways, highways, bridges, reservoir site selection, tourism development, etc. must be carried out in the case of identifying the debris flow valley and its hazard status, and try to avoid areas and sections that may cause direct harm.

Biological measures: It is a long-term treatment method that helps to slow down the formation of debris flow and achieve certain prevention and control purposes. The main methods are to close mountains for afforestation, stop farming and return to forests, consolidate topsoil, maintain water and soil, and reduce the probability and scale of debris flows.

Debris flow prevention and control measures: engineering facilities are mainly for the protection of the harmful objects from damage and other engineering facilities, such as slope protection, retaining walls, dams, dams and other projects.

Comprehensive prevention and control measures: Combine biological measures with several engineering measures applicable to a debris flow hazard area to carry out comprehensive and unified remediation of small debris flow watersheds to effectively prevent and reduce the occurrence of disasters.

<> above information for your reference.

Teacher, are you a geography teacher?

I'm not a physics teacher, but my grades in physics are still good<>

It's okay for you to ask this question.

Teacher, I can't answer these two questions.

The current generation has new questions that need to be re-inquired.

The terrain is undulating.

Due to the large undulation of the terrain in the western region, coupled with the relatively large amount of rainfall and concentrated in the rainy season, rainwater erosion increases the sliding force of the landslide at the same time, the rainwater will corrode the rock, and gradually produce cracks under the action of pressure, forming an unstable area, due to the combined action of rainwater erosion and rock corrosion, the formation of landslide debris flow.

Landslides and debris flow disasters in China are concentrated in the southwest region, because they are located at the junction of plates, the first is frequent, so the rock is damaged, and the terrain is undulating, affected by the monsoon climate, the precipitation is concentrated and the heavy rain is heavy, and the vegetation is seriously damaged, so it leads to landslides and debris flows.

Test Center: This question examines the geological disasters that affect our country.

Causes: Mountainous and steep slopes, precipitation is concentrated and heavy rainfall.

Analysis: Due to the large undulation of the terrain in the western region, coupled with the relatively large rainfall and concentrated in the rainy season, the rainwater erosion increases the sliding force of the landslide and the rainwater will corrode the rock, gradually produce cracks under the action of pressure, forming an unstable area, and the landslide debris flow is formed due to the combined action of rainwater erosion and rock corrosion.

Debris flow is different from landslides, landslides and **, it is flowing, impact and carrying capacity is great, so, when in the debris flow area, can not run down or up along the ditch, but should run to the slopes on both sides, out of the ditch, river valley area.

Landslides and debris flow disasters in China are concentrated in mountainous areas, especially in Hengduan mountainous areas. The main reasons are: high mountains and deep valleys, rugged terrain; Multi-**, strata fragmentation; Heavy rains in summer; Poor vegetation cover.

When the moist air moves horizontally, when it encounters a mountain, it "climbs" along the slope, the temperature drops, the water vapor condenses, and the precipitation is formed

So the answer is: windward; Leeward

Summary. Rivers have an erosive effect, such as the impact of the tributaries of the Yellow River on the Loess Plateau, and the erosion of the Yangtze River has created the Three Gorges.

Accumulation, such as the Yellow River alluvial out of the North China Plain, the Yellow River Delta, the Yangtze River alluvial into the Yangtze River Delta, Chongming Island.

Rainfall causes soil erosion.

When rainwater falls to the ground, it infiltrates and carries some nutrients in the soil to the deep soil, making the topsoil barren. When rainwater infiltrates, it will also bring some salts to the deep soil to reduce the salinization of the surface soil. When rainwater collects into surface runoff, it carries away some of the material in the soil, which is known as soil erosion.

Changes in the terrain caused by rivers, rainfall, etc., are all changes to the terrain.

For example, the influence of the tributaries of the Yellow River on the Loess Plateau, and the erosion of the Yangtze River created the Three Gorges. Accumulation, such as the alluvial accumulation of the Yellow River out of the North China Plain and the Yellow River Delta, and the alluvial accumulation of the Yangtze River into the Yangtze River Delta and Chongming Island. Rainfall causes soil erosion.

When rainwater falls to the ground, it infiltrates and carries some of the nutrients in the soil to the deep soil, making the topsoil barren. When rainwater infiltrates, it will also bring some salts to the deep soil to reduce the salinization of the surface soil. When rainwater collects into surface runoff, it carries away some of the material in the soil, which is known as soil erosion.

The effects of rainfall on the land are: changes in topography; Inundation and erosion of farmland and roads, causing landslides and mudslides in trapped mountains, causing loss of sail limbs to people's lives and property.