Analyzing Natural Hazards: Subsoil, Hydrology, and Atmospheric Risks

Natural Hazards and Disaster Factors

Risks Associated with Subsoil Types

Land subsidence is a process that usually does not cause direct victims but leads to significant economic losses.

• Expansive Soils: These soils can swell, compromising the stability of foundations and structures.
• Karstic Risks: Due to the morphology and linearity of limestone terrain, these risks can generate ground subsidence.

Risks Associated with Snow and Ice

• In very cold areas, the presence of snow and glaciers determines phase changes in the volume of soil water and rocks, causing swelling, cracking, and disintegration.
• The presence of glacial ice masses conditions the stable or unstable nature of associated risks.
• In Spain, risks associated with snow and ice are limited to areas of medium and high mountains, and certain low-lying areas with significant altitudes.

Risks Associated with River Dynamics (Flooding)

Flooding is the most important risk related to river dynamics. Floods occur when water covers an area that is usually not submerged.

Main Effects of Floods

• Loss of human lives (more significant the larger the settled population).
• Loss of crops and livestock.
• Economic losses in industry and commerce.
• Deterioration of infrastructure.

Causes of Floods

• Weather conditions: Heavy rainfall concentrated in a few hours.
• Thaw: The rapid melting of ice and snow on mountains.
• Coastal flood zones: Unexpected increase in sea level.
• Sudden breakage of natural levees.

Risks Associated with Atmospheric Dynamics

Torrential rains and wind phenomena are the most important weather risks.

• High Winds: Gusts reaching speeds of 80 km/h or more can cause significant damage.
• Tropical Cyclones: Very violent storms originating from warm air masses in hot water areas close to the Equator, giving rise to strong winds and rain.

Understanding Natural and Anthropogenic Disasters

Definition of Catastrophes

Catastrophes (or disasters) are events resulting from the interaction of natural phenomena with a vulnerable population. These events not only cause damage and loss but can ruin a country's economy. Events causing disasters are considered those resulting in damage of various types and degrees.

Main Effects of Catastrophes

Disasters result in human, economic, and environmental losses. Beyond the immediate loss of human life, they impact the means of production and income generation, braking development. The effects of disasters can severely impact the capacity of countries to maintain sustainable development.

Factors that Increase Catastrophe Risks

• Rampant population growth.
• Conditions of underdevelopment.
• Inadequate urbanization actions.
• Inappropriate use of high-risk technologies.
• Environmental degradation.

Classification of Disasters

Natural disasters are manifestations of nature (often associated with geological or meteorological processes). Anthropogenic processes are those resulting from human actions and development.