Geography · Year 10 · The Challenge of Natural Hazards · Autumn Term

Earthquakes: Causes and Measurement

Investigating the causes of earthquakes, their measurement, and seismic waves.

• National Curriculum Attainment Targets
• GCSE: Geography - Natural Hazards
• GCSE: Geography - Tectonic Hazards

About This Topic

This topic focuses on the specific weather hazards that affect the UK, including extreme cold, heatwaves, and, most frequently, flooding. Students examine the meteorological causes of these events, such as the meeting of different air masses and the role of the jet stream. We use recent case studies, like the Somerset Levels floods or the 'Beast from the East,' to understand the social, economic, and environmental impacts of extreme weather on British soil.

For Year 10 students, this topic makes the abstract concepts of meteorology personal and local. It highlights the UK's vulnerability even in a temperate climate and the increasing frequency of 'unprecedented' events. The curriculum also looks at how the UK manages these risks through the Met Office warning system and local flood defenses. This topic comes alive when students can analyze real-time weather data or simulate the emergency response to a local flooding event.

Key Questions

1. Explain how seismic waves are generated and measured during an earthquake.
2. Compare the Richter and Mercalli scales for measuring earthquake intensity.
3. Analyze the relationship between fault lines and earthquake occurrence.

Learning Objectives

• Explain the primary mechanisms that generate seismic waves at fault lines.
• Compare and contrast the Richter and Mercalli scales, analyzing their strengths and weaknesses in measuring earthquake impact.
• Analyze the spatial relationship between major fault lines and the historical occurrence of significant earthquakes.
• Calculate earthquake magnitude using seismograph data, demonstrating an understanding of wave amplitude and distance.

Before You Start

Plate Tectonics and Plate Boundaries

Why: Understanding how tectonic plates move and interact is fundamental to explaining the causes of earthquakes at fault lines.

Earth's Structure

Why: Knowledge of the Earth's internal layers is necessary to comprehend how seismic waves propagate through the planet.

Key Vocabulary

Fault Line	A fracture or zone of fractures between two blocks of rock. Movement along fault lines is a primary cause of earthquakes.
Seismic Waves	Waves of energy that travel through the Earth's layers, originating from the point of an earthquake's origin or an explosion.
Epicenter	The point on the Earth's surface directly above the focus, where an earthquake's rupture begins.
Magnitude	A measurement of the energy released by an earthquake, typically determined by the amplitude of seismic waves recorded on a seismograph.
Intensity	A measure of the effects of an earthquake at a particular place, based on observed damage and human reactions.

Watch Out for These Misconceptions

Common Misconception

The UK doesn't have 'real' extreme weather compared to the tropics.

What to Teach Instead

While we don't have hurricanes, our infrastructure is often not built for the extremes we do get, such as 40°C heat or prolonged heavy rain. A gallery walk of UK flood damage helps students realize the massive economic cost of 'moderate' hazards.

Common Misconception

A '1 in 100 year flood' only happens once every century.

What to Teach Instead

This is a statistical probability (1% chance every year), not a schedule. You can have two '1 in 100 year' floods in two years. Using a dice-rolling simulation helps students grasp the concept of probability in hazard planning.

Active Learning Ideas

Mock Trial: The Flooding Blame Game

Following a simulated flood event, students take on roles such as the Environment Agency, local farmers, property developers, and residents. They must argue who is responsible for the damage and who should pay for future defenses.

50 min·Whole Class

Think-Pair-Share: Social Media vs. Official Warnings

Students compare a Met Office weather warning with a viral social media post about an upcoming 'weather bomb.' They discuss the dangers of misinformation and how to communicate risk effectively to different age groups.

20 min·Pairs

Inquiry Circle: UK Weather Records

Groups are given data sets of UK temperature and rainfall from the last 100 years. They must identify trends and 'extreme' outliers, then link these outliers to specific historical weather events they have studied.

40 min·Small Groups

Real-World Connections

• Structural engineers use seismograph data and intensity scales to design earthquake-resistant buildings and infrastructure in seismically active regions like California and Japan, ensuring public safety.
• Emergency management agencies, such as FEMA in the United States, utilize earthquake prediction models and historical data to plan evacuation routes and allocate resources for disaster response following major seismic events.
• Geologists working for oil and gas exploration companies analyze fault lines and seismic activity to assess geological risks and identify potential resource locations.

Assessment Ideas

Quick Check

Provide students with a simplified seismograph reading showing P-wave and S-wave arrival times. Ask them to calculate the time difference between the waves and explain what this difference indicates about the earthquake's distance from the seismograph.

Discussion Prompt

Present students with descriptions of two different earthquake scenarios: one with a high Richter magnitude but low observed damage, and another with a lower magnitude but significant destruction. Ask: 'Which earthquake would be described as more intense, and why? How do the Richter and Mercalli scales help us understand these differences?'

Exit Ticket

On an index card, ask students to draw a simple diagram illustrating the relationship between a fault line, the focus, and the epicenter of an earthquake. They should label each component and write one sentence explaining how fault movement causes seismic waves.

Frequently Asked Questions

What is the 'Beast from the East'?

It was a period of extreme cold and heavy snow in early 2018 caused by a change in the jet stream that brought cold air from Siberia to the UK. It caused widespread disruption to transport, school closures, and several deaths, highlighting the UK's lack of resilience to extreme cold.

How does the Met Office warn people about weather?

The Met Office uses a color-coded system: Yellow (be aware), Amber (be prepared), and Red (take action). These warnings are based on both the likelihood of the event and the potential impact it will have on people and infrastructure.

Why is the UK getting more flooding?

It is a combination of climate change (warmer air holds more moisture, leading to heavier rain) and human factors like building on floodplains and increased paving in urban areas, which increases surface runoff. Students should consider both factors in their exam answers.

How can active learning help students understand UK weather hazards?

Active learning, such as role-playing a local council meeting, helps students understand that weather management is not just about science, it's about money, politics, and community priorities. By analyzing real hydrographs and weather maps in groups, students develop the practical skills needed to interpret geographical data, making the theory of 'extreme weather' much more concrete.