Earthquakes, volcanic eruptions and volcano opportunities
Describe earthquake and eruption features, interpret earthquake location and magnitude, and weigh opportunities people may gain from volcanoes.
Section 6 · Natural hazards
This original StudyForA sequence supports Cambridge IGCSE Environmental Management 0680 Topics 1–4 for exams in 2027, 2028 and 2029. Named local examples are chosen by the learner and centre; verify current conditions and local context with reliable sources. It is not a Cambridge paper, official grade or complete course.
Before you begin
- Use the 2027–2029 syllabus and check your exam year and centre's entry arrangements. Topics 1–4 are taught on this page; Topics 5–7 are still being built.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which scale is named for earthquake magnitude?
What you will learn
- Describe earthquake and eruption features, interpret earthquake location and magnitude, and weigh opportunities people may gain from volcanoes.
- Use evidence from an unfamiliar case to explain a cause-and-effect link and justify a suitable response.
Describe an earthquake
An earthquake releases energy. The focus is where the earthquake starts within Earth, and the epicentre is the point on Earth's surface directly above the focus.
Earthquake magnitude is measured using the Moment Magnitude Scale. Do not confuse the focus with the surface location or treat magnitude as the same as the number of people affected.
Recognise volcanic eruption features
Magma rising to Earth's surface forms lava. Eruptions can also produce ash, water vapour, carbon dioxide and sulfur dioxide, acid rain, volcanic bombs and pyroclastic flows.
The materials and processes create different hazards. A pyroclastic flow is a fast-moving hot mixture; ash and gases can travel beyond the vent, depending on conditions.
Explain opportunities and trade-offs
Volcanoes can provide fertile soils, minerals, building materials, geothermal power and tourism. These may support farming, industry, energy supply and local income.
People living near volcanoes also face risk. An opportunity should be evaluated alongside exposure, monitoring, preparedness and the cost of maintaining safe development.
Sources for this lesson
Pause and explain
Which is an opportunity provided by volcanoes?
Worked example
An earthquake begins beneath a settlement and a nearby volcano erupts. Define focus and epicentre, name two eruption products and one opportunity from the volcanic setting.
Show the worked solution
- The focus is where earthquake energy is released; the epicentre is the point on the surface above it.
- The eruption may produce lava and ash, gases, acid rain, bombs or pyroclastic flows.
- A local opportunity could include fertile soil, geothermal power or tourism, but its benefit needs to be weighed against hazard exposure.
Answer The focus is underground and the epicentre is directly above it at the surface. Volcanic products include lava and ash, while opportunities such as fertile soils do not remove the need to manage risk.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
An earthquake begins 12 km below a town. Explain what the 12 km describes and where the epicentre would be located.
Give me a hint
Distinguish the underground focus from the surface point above it.
Compare my reasoning
- The location where energy is released underground is the focus.
- The epicentre is at Earth's surface directly above the focus.
- The Moment Magnitude Scale measures earthquake magnitude; depth and magnitude describe different features.
The 12 km depth locates the focus. The epicentre is the surface point directly above it.
Look for these in your work
- Focus identified
- Epicentre located
- Magnitude distinguished from depth
A volcano supplies fertile soil and geothermal energy to a community. Explain two benefits and one reason the community still needs hazard planning.
Give me a hint
Balance opportunities with the possibility and consequences of eruptions.
Compare my reasoning
- Fertile soils can support farming and food production.
- Geothermal power can provide an energy resource where the setting is suitable.
- Eruptions may produce ash, gases, lava, bombs or pyroclastic flows, so monitoring and preparation are still needed.
Fertile soil and geothermal energy are opportunities, but volcanic hazards remain possible and need active management.
Look for these in your work
- Two opportunities explained
- At least one eruption hazard named
- Need for planning retained
Two towns have similar volcanic opportunities, but one is closer to a likely flow path and has fewer evacuation routes. Explain why their risk and planning needs differ.
Give me a hint
Separate the hazard from exposure and capacity to respond.
Compare my reasoning
- Both towns may benefit from fertile soil, resources, energy or tourism.
- The town near a likely flow path has greater exposure to that hazard.
- Fewer evacuation routes can reduce response capacity, so land use, warning and evacuation planning should reflect the local evidence.
Similar opportunities do not mean equal risk. Exposure and response capacity differ, so planning must be specific to each town.
Look for these in your work
- Opportunity acknowledged
- Exposure compared
- Response capacity considered
Common mistakes
- Calling the epicentre the underground starting point
- Confusing magma beneath the surface with lava at the surface
- Treating every eruption product as equally mobile
- Discussing tourism without considering volcanic risk
What can you explain now?
What is the epicentre?
Compare with the explanation
The surface point directly above the earthquake focus
The correct answer is “The surface point directly above the earthquake focus”. The alternatives “The underground point where an earthquake begins” and “The point where lava cools into rock” do not match the syllabus concept. Describe earthquake and eruption features, interpret earthquake location and magnitude, and weigh opportunities people may gain from volcanoes.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Distinguish earthquake focus and epicentre, describe eruption features and evaluate opportunities alongside risk.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.