Types of Natural Hazards

Natural hazards are events caused by environmental processes and have the potential to cause harm to the environment, people, or the economy.

These hazards occur without the influence of humans, but their impact is significant when they interact with human activities. Understanding the different types of natural hazards is important for assessing risk and implementing appropriate measures to reduce their effects.

Categorising Natural Hazards

Natural hazards can be categorised based on their causes.

Tectonic Hazards

Tectonic Hazards are hazards associated with the movement and interaction of the Earth’s tectonic plates. These hazards result from geological processes occurring beneath the Earth’s surface. For example:

  • Earthquake – A sudden shaking or trembling of the ground caused by the movement of tectonic plates beneath the Earth’s surface.
  • Volcanic Eruption – The release of molten rock, ash, and gases from a volcano, often accompanied by explosions and lava flows.
  • Tsunami – A series of ocean waves triggered by large-scale disturbances, such as underwater earthquakes or volcanic eruptions.

Geomorphological Hazards

Geomorphological Hazards are hazards from natural processes shaping the Earth’s surface. These hazards are caused by various geomorphological phenomena, such as erosion, deposition and slope instability. For example:

  • Floods – Overflow of water onto normally dry land, usually caused by heavy rainfall, melting snow, or dam failure.
  • Landslides – The movement of soil, rocks, or debris down a slope, often triggered by excessive rainfall, earthquakes, or human activities.

Atmospheric Hazards

Atmospheric Hazards are hazards related to weather and atmospheric conditions. These hazards result from natural atmospheric processes, including storms, extreme temperatures and other weather-related phenomena. For example:

  • Tropical Storms – Intense low-pressure systems with strong winds and heavy rainfall, such as hurricanes, typhoons, or cyclones.
  • Droughts – Prolonged periods of significantly below-average rainfall, resulting in water shortages and dry conditions.
  • Tornadoes – Violently rotating columns of air extending from a thunderstorm to the ground, capable of causing severe damage.

Biological Hazards

Biological Hazards are hazards associated with living organisms and ecological systems. These hazards involve the transmission of diseases, the impact of invasive species on ecosystems and the harmful effects of pests on human health, agriculture, or the environment.

  • Pests – Organisms that negatively impact human health, agriculture, ecosystems, or the economy, such as insects, rodents, or invasive species.
  • Diseases – Illnesses or conditions caused by pathogenic microorganisms, including viruses, bacteria, parasites, or fungi.

Factors Affecting Hazard Risk

Hazard risk refers to the probability of an area or population being affected by a natural hazard. Several factors influence the level of hazard risk:

  • Population – The growing world population leads to more people residing in areas vulnerable to natural hazards. This increases the potential impact on human lives and infrastructure.
  • Urbanisation and Population Density – Urban areas with higher population density are more susceptible to the effects of natural hazards due to concentrated human settlements and infrastructure.
  • Frequency and Magnitude – The frequency and intensity of hazard events play a crucial role in determining the level of risk. Higher frequency or more severe events pose a greater risk.
  • Level of Development – High-income countries are generally better prepared and more resilient in dealing with the effects of natural hazards compared to low-income countries and newly emerging economies.
  • Prediction – The ability to predict specific hazards, such as earthquakes, plays a significant role in mitigating their impact. A lack of predictability can increase vulnerability.
  • Human Activities – Human actions, such as deforestation and urbanisation, can heighten the level of hazard risk by altering natural processes and increasing exposure to hazards.