Year 8 Geography: Natural Hazards and Tectonic Activity

What Are Natural Hazards?

Natural hazards are extreme events that can cause damage to people, property, and the environment. They include things like earthquakes, volcanoes, floods, and storms. In this lesson, we will focus on one type of natural hazard: tectonic activity.

What is Tectonic Activity?

Tectonic activity relates to the movement of the Earth’s plates. The Earth’s crust is made up of large pieces called tectonic plates. These plates are constantly moving, but they move very slowly—only a few centimetres each year!

Key Points to Understand

1. Tectonic Plates: The Earth’s surface is divided into several large and small plates. They float on a hot, semi-fluid layer called the mantle.
2. Plate Boundaries: Where these plates meet is called a boundary. There are three main types of plate boundaries:
   • Convergent Boundaries: Plates push against each other. This can cause earthquakes and mountains to form.
   • Divergent Boundaries: Plates move apart from each other. This can cause volcanic activity.
   • Transform Boundaries: Plates slide past each other. This can also lead to earthquakes.
3. Natural Hazards: The movement of tectonic plates can lead to natural hazards like:
   • Earthquakes: Sudden shaking of the ground caused by the release of energy when plates move.
   • Volcanoes: When magma from inside the Earth escapes to the surface, we get a volcanic eruption.

Examples of Tectonic Activity

• Earthquake: The 2011 earthquake in Japan was caused by tectonic movements along a convergent boundary, leading to significant destruction and a tsunami.
• Volcano: Mount Vesuvius in Italy is a famous volcano that erupted in AD 79, burying the city of Pompeii.

Tips and Tricks to Remember

• Think of tectonic plates like a big jigsaw puzzle that keeps changing shape.
• Use maps to see where earthquakes and volcanoes are located. Most of these hazards occur along the edges of tectonic plates.
• Remember the three types of plate boundaries: convergent, divergent, and transform. This will help you understand how different natural hazards occur.

Questions to Test Your Knowledge

Easy Level Questions

1. What are natural hazards?
2. What are tectonic plates?
3. What is the mantle?
4. Name one type of natural hazard.
5. What happens at a convergent boundary?
6. What happens at a divergent boundary?
7. What happens at a transform boundary?
8. Give an example of an earthquake.
9. Give an example of a volcano.
10. Why do tectonic plates move?

Medium Level Questions

11. What is an earthquake?
12. How can earthquakes affect buildings?
13. What causes volcanic eruptions?
14. Describe what happens during a volcanic eruption.
15. Where do most earthquakes occur?
16. What is the Ring of Fire?
17. How do scientists measure earthquakes?
18. What is the difference between magma and lava?
19. How can we prepare for earthquakes?
20. Why are some areas more prone to tectonic activity than others?

Hard Level Questions

21. Explain the difference between primary and secondary effects of earthquakes.
22. How do tectonic movements create mountains?
23. What role do tectonic plates play in creating tsunamis?
24. Describe how scientists predict volcanic eruptions.
25. What is subduction, and why is it important?
26. How do human activities impact tectonic activity?
27. What is faulting?
28. Name a country that is located on a transform boundary.
29. Discuss the social and economic impacts of a major earthquake.
30. How can technology help in disaster management related to tectonic hazards?

Answers and Explanations

Easy Level Answers

1. Natural hazards are extreme events that can cause damage.
2. Tectonic plates are large pieces of the Earth’s crust.
3. The mantle is a semi-fluid layer below the Earth’s crust.
4. Earthquake, volcano, flood, or storm.
5. Plates push against each other, which can cause earthquakes.
6. Plates move apart from each other, leading to volcanic activity.
7. Plates slide past each other, causing earthquakes.
8. The 2011 Japan earthquake.
9. Mount Vesuvius.
10. They move due to heat and convection currents in the mantle.

Medium Level Answers

11. An earthquake is the shaking of the ground caused by the movement of tectonic plates.
12. Earthquakes can cause buildings to collapse, leading to injuries and loss of life.
13. Magma rises to the surface due to pressure and can result in a volcanic eruption.
14. During a volcanic eruption, magma escapes from the Earth, causing lava flows and ash clouds.
15. Most earthquakes occur along plate boundaries.
16. The Ring of Fire is a region in the Pacific Ocean with many earthquakes and volcanoes.
17. Scientists measure earthquakes using a seismometer.
18. Magma is molten rock inside the Earth; lava is molten rock that reaches the surface.
19. We can prepare for earthquakes by having emergency kits and plans.
20. Areas near plate boundaries experience more tectonic activity.

Hard Level Answers

21. Primary effects are immediate impacts like shaking; secondary effects are long-term impacts like tsunamis.
22. Tectonic movements push the Earth’s crust up, forming mountains.
23. Tectonic movements can displace water, creating tsunamis.
24. Scientists study seismic activity and gas emissions to predict eruptions.
25. Subduction is when one plate goes beneath another; it can cause earthquakes and volcanoes.
26. Human activities like mining can induce minor seismic activity.
27. Faulting is the breaking of rocks along a fault line due to stress.
28. The San Andreas Fault in California.
29. Major earthquakes can lead to loss of life, displacement, and economic loss.
30. Technology like GPS can monitor plate movements and enhance preparedness.

By understanding tectonic activity and its effects, we can better prepare for and respond to natural hazards. Keep exploring this fascinating subject!