What this lesson teaches
I can explain the hazards, impacts and benefits of earthquakes and volcanoes for nature and people.
Syllabus K329, Topic 4.2, Key Question 4. How might tectonic hazards affect the natural and human systems?
Make a guess
Millions of farmers live on the slopes of volcanoes in Java, Indonesia. What is the most likely reason?
- Volcanoes in farming areas have stopped erupting.
- Fresh ash helps crops grow straight away.
- Weathered volcanic ash makes fertile soil.
- The government forces them to live there.
Show the answer
Weathered volcanic ash makes fertile soil.
As volcanic deposits break down, they release mineral nutrients. Over time this forms rich soil that supports farming.
Volcanic areas can offer fertile soil, minerals, geothermal energy and tourism, which helps explain why people live near them.
Volcanic soils can support farming once the deposits weather, or break down, and release mineral nutrients. Fertile soil takes time to form, and also needs suitable climate, drainage and care. Fresh ash may first bury crops and farmland.
Volcanic activity and hot water underground can concentrate valuable minerals. Basalt, pumice and other deposits are used as building materials. Mining and quarrying provide jobs and construction materials, but poor management can scar landscapes, pollute water and endanger workers.
Volcanic heat warms underground water, which can be used for geothermal electricity or heating. This needs heat, water, permeable rock, technology and investment. Not every volcano offers a usable energy source, and development still needs environmental care.
Scenery, hot springs and geological heritage attract visitors, supporting guides, hotels and other services. Tourism adds jobs, but can collapse when a volcano becomes restless. It can also bring people into danger zones, so access and information must follow the monitoring.
People may stay for work, family, culture or land they own. Some cannot afford to move or have no alternatives. So weigh these benefits and limits against the hazards. Monitoring, planning and livelihoods that can survive disruption are still needed.
- Fertile soil
- Weathered volcanic material releases nutrients over time.
- Geothermal energy
- Volcanic heat used for power or heating.
- Tourism
- Scenery and hot springs create jobs.
Step by step
Materials help livelihoods
Soil, minerals and building stone.
Heat and scenery add value
Geothermal power and tourism.
People weigh options
Work, family, land and the cost of moving.
Real examples to use
Iceland
About 90% of homes in Iceland are heated with geothermal hot water from underground.
Java, Indonesia
Millions of farmers live on the slopes of volcanoes such as Merapi because weathered volcanic ash makes very fertile soil.
Worked example: Loss now, benefit later
An ash fall can destroy this year's crop. Yet older volcanic deposits, weathered over time, make the region's soil rich. Both are true, over different timescales.
Watch out for this
Fertile soil means eruptions help everyone straight away.
Fresh ash can destroy crops. Soil takes time to form, and benefits are shared unequally.
Check your understanding
How do volcanoes help farming?
- Fertile land makes the slopes safer, so farmers can stay.
- Weathering releases nutrients and forms fertile soil.
- Each fresh ash fall improves the crops straight away.
Show the answer
Weathering releases nutrients and forms fertile soil.
Yes. The benefit takes time.