Understanding Natural Hazards and Risk Mitigation

A natural hazard is the probability that a small or large population in an area suffers damage or a catastrophe as a result of natural processes.

Factors:

• Hazard Probability: Probability of occurrence in a geographical area at a determined time. Depends on geographical areas of distributions of certain natural phenomena.
• Geographic Area Affected: Recurrence interval or return period.
• Degree of Danger: Characteristics of the phenomenon and intensity of interference.
• Vulnerability: Total human and material assets exposed to risk factors, such as population density and the economic value of assets exposed.
• Harm: The percentage of human life or property exposed that can be affected by a natural phenomenon.

Factors Influencing Harm:

• Existence of prevention plans to prevent or mitigate damage.
• Response measures that exist when damage occurs.

Erosion is the removal of materials from one area due to agents involved in external geological processes.

Reasons for Erosion:

• Loss of resources.
• Action of the materials themselves when immobilized.

Gravitational Processes and Associated Risks:

The possibility that moving materials can hit, raze, or bury persons or buildings. The fact is based on those people, infrastructure, etc., moving down the slope.

Actions to Prevent Gravity Risks:

• Reduction of the inclination of the slope.
• Removal of weight in addition to head and foot.
• Strengthening and adding weight to the foot of the slope.
• Drainage.
• Reinforcement anchors.

The prediction, anticipation, and prevention of natural catastrophes is to identify processes and risk factors that can pose a danger to the population in a determined area.

• Prediction: Knowing and announcing before a phenomenon occurs, the place and time it will occur.
• Provision: Defining in advance the likelihood of a phenomenon occurring and its different levels of intensity.
• Prevention: Includes all measures and activities implemented to avoid the detrimental impact of dangerous phenomena.
• Mitigation: Implementing all decisions and protections established before a disaster occurs because of certain anticipated risks. These measures can range from the construction of resistant buildings to the application of risk evaluation techniques.

Causes of Floods:

• Weather conditions
• Melting
• Coastal flooding
• The snapping of natural dikes
• Anthropogenic causes

Risks Associated with the Type of Subsoil:

• Risks due to subsidence or subsidence.
• Risks due to expansive soils.
• Risks due to karst formations.

Risks Associated with River Dynamics:

Floods occur when water covers land not usually submerged.

Effects:

• Loss of human lives.
• Loss of crops and livestock.
• Economic losses.
• Deterioration of infrastructure.

Littoral Processes:

Factors:

• Coastal geological processes.
• Large storms.
• Human activities.

Volcano Hazard:

• The explosiveness of eruptions.
• Type of exhaust products.
• Lahars.
• Lava.

Seismic Precursors:

• Seismic movements in the vicinity of the volcano.
• Elevations.
• Changes in magnetic fields.
• Anomalies in the value of gravity.
• Fumaroles and hot springs.