AQA GCSE Geography

## What a natural hazard is A **natural hazard** is a natural event that threatens people and property. The event itself is only a hazard when people or their buildings are in its way: an earthquake in an uninhabited part of Antarctica is a natural event, while the same earthquake under a city is a hazard. The harm a hazard does depends on where it happens, how strong it is and how well the people there are prepared. ## Types of natural hazard Natural hazards fall into groups according to the process behind them. | Group | Examples | Cause | |---|---|---| | Geological (tectonic) | Earthquakes, volcanic eruptions, tsunamis | Movement of the Earth's crust and release of magma | | Geomorphological | Landslides, avalanches, coastal erosion | Gravity acting on slopes, waves acting on cliffs | | Atmospheric (weather) | Tropical storms, tornadoes, droughts, heatwaves, blizzards | Conditions in the atmosphere | | Hydrological | Floods, storm surges | Excess water from rain, rivers or the sea | Some hazards trigger others. An earthquake under the sea can cause a tsunami, an earthquake on land can cause landslides, and a tropical storm brings both flooding from rainfall and a storm surge along the coast. These secondary hazards often do as much harm as the original event. ## Factors that affect hazard risk **Risk** is the chance that a hazard will cause harm to people and property in a particular place. Some factors raise the risk and others lower it, which is why identical hazards…