Earthquakes and Volcanoes
Natural Hazards - Plate Tectonics - Geomorphology
Earthquakes and volcanoes are usually taught together because both are linked to plate movement. In Grade 10 Geography, you need to know how they happen, how they are measured or classified, and what effects they have on people and the environment.
Earthquakes
A sudden vibration or shaking of the Earth's crust, caused by the release of energy along geological faults.
Key Anatomy
Focus
The actual point deep underground where the earthquake begins.
Epicentre
The point on the surface directly above the focus; most intense shaking.
Seismic Waves
Energy released travels as waves through the Earth.
Seismic Waves
P-waves
Primary waves - fastest, travel through solids and liquids.
S-waves
Secondary waves - slower, travel only through solids.
L-waves
Surface waves - cause the most damage due to rolling motion.
Measurement
Seismograph
Instrument that records the force and duration of an earthquake.
Richter Scale
Magnitude scale (1-10); each step = 10x amplitude and about 31.6x energy.
Mercalli Scale
Intensity scale based on observed physical damage.
Impacts
Building Collapse
Structural failures causing loss of life and property.
Tsunamis
Underwater earthquakes displace water, devastating coastlines.
Landslides
Shaking triggers landslides in hilly regions.
Volcanoes
Openings in the Earth's crust allowing magma, ash, and gases to escape.
Classification by Activity
Active
Currently erupting or showing signs of potential eruption.
Dormant
"Sleeping" but expected to erupt again.
Extinct
Not expected to erupt again.
Main Types of Volcanoes
Shield Volcano
Broad, gentle slopes from low-viscosity lava.
Composite (Stratovolcano)
Steep-sided cones from alternating ash and viscous lava.
Cinder Cone
Small, conical mounds from ejected volcanic fragments.
Human & Environmental Impact
Negative Impacts
- Loss of life and injuries
- Destruction of infrastructure
- Air pollution from volcanic ash
Positive Impacts
- Fertile soil from volcanic ash
- Geothermal energy
- Tourism (geysers, volcanic landscapes)
Practice & Assess
Six interactive games to test your knowledge. Each game has a working reset button.
Quiz 1 - Earthquake Anatomy
Where does an earthquake begin underground?
Quiz 2 - True/False
"S-waves travel through liquids."
Match - Volcano Types
Fill - Surface Point
The point on the surface directly above the focus is the ______ .
Fill - Magnitude Scale
The ______ Scale measures earthquake magnitude from 1-10.
Order - Activity Status
Arrange from most active to least active (click to reorder):
Key Terms
Key Recap
Keep the basics clear: earthquakes release energy along faults, while volcanoes allow magma and gases to escape to the surface. In tests, learners should be able to define the main terms, identify hazards, and give both negative and positive effects.
