Definition and types of natural hazard, hazard risk; plate tectonics theory, plate margins, and the effects of and responses to a tectonic hazard in a contrasting pair of countries.

What this dot point is asking

This is AQA GCSE Geography (8035) Paper 1, Section A (3.1.1 The challenge of natural hazards). AQA expects you to define a natural hazard, classify hazard types, explain the factors that affect hazard risk, describe the structure of the Earth and the theory of plate tectonics, distinguish the three plate margins, and use a named example of a tectonic hazard in two contrasting countries to explain primary and secondary effects, immediate and long-term responses, and why people continue to live in hazardous areas.

Types of natural hazard and hazard risk

A natural hazard is a natural event (such as an earthquake, tropical storm or flood) that has the potential to cause loss of life or damage to property. Hazards are usually grouped as tectonic (earthquakes, volcanoes) and atmospheric (storms, drought).

Plate tectonics theory

The Earth has a dense core, a semi-molten mantle, and a thin outer crust broken into tectonic plates. Convection currents in the mantle, driven by heat from the core, drag the plates and make them move. There is thin, dense oceanic crust and thick, less dense continental crust.

The three plate margins

• Constructive (divergent): plates move apart, magma rises to form new crust and gentle volcanoes (for example the Mid-Atlantic Ridge under Iceland).
• Destructive (convergent): an oceanic plate is subducted under a continental plate, melting to feed explosive volcanoes and triggering powerful earthquakes.
• Conservative (transform): plates slide past each other; no crust is made or destroyed, but friction causes strong earthquakes (for example the San Andreas Fault).

Contrasting tectonic hazards: Nepal and Italy

The 2015 Nepal earthquake (magnitude 7.8) struck a lower-income country. Primary effects: about 9,000 deaths and 600,000 buildings destroyed. Secondary effects: avalanches on Everest and landslides blocking roads. Immediate responses relied on international aid; long-term responses included repairing heritage sites to restore tourism.

The 2009 LAquila earthquake in Italy (magnitude 6.3) struck a higher-income country. There were around 300 deaths and 67,000 left homeless, but better building standards, organised search-and-rescue, insurance and a wealthier economy meant recovery was faster. Comparing the two shows that magnitude alone does not decide the impact: the Nepal quake was stronger yet caused far more death and damage largely because of poverty, building quality and remote terrain. This is the core "level of development" point AQA wants in the higher-mark answers.

Why people live in hazardous areas. Despite the risk, people stay in tectonic regions for fertile volcanic soils (the slopes of Mount Etna and Vesuvius are intensively farmed), geothermal energy (Iceland generates much of its electricity and heating from it), tourism (volcanoes and hot springs attract visitors and income), mineral deposits, and simply because it is home, with family, jobs and community ties that are hard to leave. Many also judge that a major event is rare in their lifetime, or trust that monitoring, building codes and planning will protect them.

Try this

Q1. Define the term hazard risk. [2 marks]

• Cue. The probability or chance that a community will be affected by a natural hazard.

Q2. Explain why earthquakes occur at conservative plate margins. [2 marks]

• Cue. Plates slide past each other, friction locks them, and the sudden release of built-up pressure causes the earthquake.