What Are Natural Hazards?
Natural hazards are natural events that pose a threat to people, property, infrastructure, and the environment. Hazards only become disasters when they affect people and cause significant damage.
Natural hazards can be grouped into two main categories:
Tectonic Hazards
These are caused by movements of the Earth’s tectonic plates.
Examples:
- Earthquakes
- Volcanic eruptions
- Tsunamis
Atmospheric Hazards
These are caused by weather and climate processes.
Examples:
- Tropical storms
- Droughts
- Flooding
- Heatwaves
- Blizzards
Tectonic Hazards
The Structure of the Earth
The Earth is made up of four main layers:
- Crust
- Mantle
- Outer Core
- Inner Core
The Earth’s crust is broken into tectonic plates that move slowly due to convection currents in the mantle.
Plate Margins
Constructive Plate Margins
- Plates move apart.
- Magma rises to fill the gap.
- New crust is formed.
- Volcanoes and small earthquakes occur.
Destructive Plate Margins
- Plates move towards each other.
- The denser oceanic plate is subducted beneath the continental plate.
- Powerful earthquakes and volcanoes occur.
Conservative Plate Margins
- Plates slide past each other.
- Friction causes pressure to build up.
- Sudden release of energy causes earthquakes.
Earthquakes
Causes
Earthquakes happen when tectonic plates become stuck due to friction. Pressure builds up and is released suddenly, creating seismic waves.
Effects
Primary Effects
Immediate impacts:
- Buildings collapse.
- Roads and bridges are damaged.
- Injuries and deaths occur.
- Power and water supplies may fail.
Secondary Effects
Impacts that happen later:
- Fires from damaged gas pipes.
- Tsunamis.
- Landslides.
- Disease outbreaks.
Reducing Impacts
- Earthquake-resistant buildings.
- Emergency planning.
- Public education.
- Monitoring and hazard mapping.
Volcanoes
How Volcanoes Form
At constructive and destructive plate margins, magma rises through cracks in the Earth’s crust. When it reaches the surface, it erupts as lava.
Benefits of Volcanoes
- Fertile soils for farming.
- Tourism opportunities.
- Geothermal energy.
- Valuable minerals.
Problems Caused by Volcanoes
- Death and injury.
- Damage to buildings and infrastructure.
- Air pollution from ash.
- Destruction of crops and habitats.
Managing Volcanic Hazards
- Monitoring seismic activity.
- Measuring gas emissions.
- Using satellite imagery.
- Evacuation plans.
Tropical Storms
Conditions Needed for Formation
- Sea temperatures above 27°C.
- Deep warm ocean water.
- Low wind shear.
- Formation between 5° and 30° north and south of the Equator.
Formation Process
- Warm ocean water evaporates.
- Warm moist air rises.
- Air cools and condenses.
- Heat is released, providing energy.
- Air spirals inward due to the Earth’s rotation.
- A tropical storm develops.
Effects
- Strong winds.
- Heavy rainfall.
- Storm surges.
- Flooding.
- Damage to homes and infrastructure.
Managing Tropical Storms
- Early warning systems.
- Evacuation procedures.
- Emergency shelters.
- Improved building design.
Climate Change and Natural Hazards
Climate change may increase:
- Heatwaves.
- Droughts.
- Intense rainfall events.
- Flooding.
- Stronger tropical storms.
Mitigation
Reducing climate change by:
- Using renewable energy.
- Improving energy efficiency.
- Planting trees.
- Reducing greenhouse gas emissions.
Adaptation
Adjusting to the effects by:
- Building flood defences.
- Conserving water supplies.
- Designing heat-resistant buildings.
- Improving warning systems.
GCSE Practice Questions
1 Mark Questions
Q1
What is a natural hazard?
Q2
Name one tectonic hazard.
Q3
Name one atmospheric hazard.
Q4
What is the name of the layer beneath the Earth’s crust?
2 Mark Questions
Q5
Give two primary effects of an earthquake.
Q6
State two conditions needed for a tropical storm to form.
Q7
Give two benefits of living near a volcano.
Q8
Give two examples of secondary effects of an earthquake.
3 Mark Questions
Q9
Explain how a conservative plate margin causes earthquakes.
Q10
Explain why people continue to live in volcanic areas.
Q11
Explain how tropical storms can cause flooding.
Q12
Explain how climate change may increase the risk of natural hazards.
4 Mark Questions
Q13
Describe the differences between primary and secondary effects of an earthquake.
Q14
Explain how monitoring can help reduce the impacts of volcanic eruptions.
Q15
Explain how preparation can reduce the impacts of tropical storms.
6 Mark Questions
Q16
Explain the formation of a tropical storm.
Q17
Explain the causes of earthquakes at destructive plate margins.
Q18
Assess the advantages and disadvantages of living near a volcano.
9 Mark Questions
Q19
“Monitoring and prediction are the most effective ways of reducing the impacts of tectonic hazards.” Evaluate this statement.
Q20
“Climate change is increasing the challenge of managing natural hazards.” To what extent do you agree?
Answers
Q1 (1 Mark)
A natural event that threatens people, property, or the environment.
Q2 (1 Mark)
Earthquake.
Q3 (1 Mark)
Tropical storm.
Q4 (1 Mark)
Mantle.
Q5 (2 Marks)
- Buildings collapse.
- Roads and bridges are damaged.
Q6 (2 Marks)
- Sea temperatures above 27°C.
- Low wind shear.
Q7 (2 Marks)
- Fertile soil for farming.
- Tourism creates jobs and income.
Q8 (2 Marks)
- Tsunamis.
- Landslides.
Q9 (3 Marks)
At a conservative plate margin, two plates move past each other. Friction causes the plates to become stuck. Pressure builds up and is released suddenly, causing an earthquake.
Q10 (3 Marks)
People continue to live near volcanoes because the soil is fertile for farming. Tourism provides jobs and income. Some volcanic areas also offer geothermal energy.
Q11 (3 Marks)
Tropical storms bring very heavy rainfall. Rivers can overflow and drainage systems may become overwhelmed. This leads to flooding of homes and land.
Q12 (3 Marks)
Climate change causes higher temperatures and warmer oceans. This can increase the intensity of storms and lead to more extreme weather such as floods and heatwaves.
Q13 (4 Marks)
Primary effects happen immediately after an earthquake, such as building collapse and injuries. Secondary effects occur after the event and are triggered by the initial damage. Examples include fires, landslides, and tsunamis.
Q14 (4 Marks)
Scientists monitor earthquakes, gas emissions, and ground movement around volcanoes. These signs can indicate an eruption is likely. Warnings can then be issued and people evacuated. This helps reduce deaths and injuries.
Q15 (4 Marks)
Preparation includes emergency plans, evacuation routes, and public education. Early warnings allow people to leave dangerous areas. Stronger buildings can also reduce damage caused by high winds and flooding.
Q16 (6 Marks)
Tropical storms form over oceans where temperatures exceed 27°C. Warm water evaporates and moist air rises. As the air rises, it cools and condenses to form clouds. Heat is released, giving the storm more energy. More air is drawn into the low-pressure system and begins to spin because of the Earth’s rotation. Over time, the storm grows stronger and develops into a tropical storm.
Q17 (6 Marks)
At a destructive plate margin, an oceanic plate moves towards a continental plate. The denser oceanic plate is forced beneath the continental plate in a process called subduction. Friction causes pressure to build up between the plates. When the pressure is released, seismic waves are produced. These waves travel through the Earth and cause an earthquake.
Q18 (6 Marks)
Living near a volcano has several advantages. Volcanic soils are fertile and support farming. Tourism creates employment and income, while geothermal energy can provide electricity. However, eruptions can cause deaths, destroy homes, and damage infrastructure. Overall, although there are significant risks, the economic benefits encourage many people to remain in these areas.
Q19 (9 Marks)
Monitoring and prediction are important because they provide warnings before volcanic eruptions and allow evacuations to take place. This can greatly reduce loss of life. However, earthquakes are difficult to predict accurately, which limits the effectiveness of these methods. Other strategies such as earthquake-resistant buildings, hazard mapping, emergency planning, and public education can also reduce impacts. Developed countries often have better resources to invest in these measures. Overall, monitoring and prediction are effective, but they work best when combined with planning and protection strategies.
Q20 (9 Marks)
Climate change is making natural hazard management more difficult because it increases the frequency and intensity of some weather-related hazards. Stronger storms, heatwaves, droughts, and flooding can affect larger numbers of people. However, tectonic hazards such as earthquakes and volcanoes remain highly destructive and can occur without warning. Effective management requires both mitigation of climate change and adaptation to changing conditions. Overall, I agree to a large extent because climate change increases the risk of multiple hazards across many regions of the world and creates long-term challenges for governments and communities.
