Why Earthquakes Happen
Understand that earthquakes happen when rocks underground suddenly move or break, releasing energy that shakes the ground
What a learner can do afterwards
- Explain that earthquakes are caused by rocks underground suddenly moving
- Describe how this movement sends shaking through the surrounding ground
- Distinguish between the underground cause and the surface effects of an earthquake
The lesson
Far under the ground, huge slabs of rock press against each other all the time. For a while they hold still, even though they are being pushed hard. Then, when the push gets too strong, the rocks suddenly slip or crack. That sudden movement is what starts an earthquake.
Think about bending a ruler. At first it just bends, and nothing happens. Push harder, and it holds a little longer, then suddenly snaps. Underground rocks act the same way. They hold under pressure, then suddenly break or slip, and that sudden break sends shaking out into the ground around it.
Remember: the cause of an earthquake happens underground, where the rocks move. The shaking you feel is the effect, and it can travel far from the spot where the rocks actually broke.
Earthquakes start when underground rocks suddenly move or break, sending shaking out through the ground around them.
Watch it
Where it sits
Learn first
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.