---
title: "Why Earthquakes Happen"
description: "Explain how sudden movement of rocks underground releases energy that shakes the ground"
canonical: https://lightmysky.com/learn/science/why-earthquakes-happen-mt_NVr4AhsvIq
source: https://lightmysky.com/learn/science/why-earthquakes-happen-mt_NVr4AhsvIq.md
retrieved: 2026-10-19
---

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# Why Earthquakes Happen

Explain how sudden movement of rocks underground releases energy that shakes the ground

Subject: Science · Area: Volcanoes & Earthquakes · Ages 7 to 9
Page: https://lightmysky.com/learn/science/why-earthquakes-happen-mt_NVr4AhsvIq

## Ready when they can

- 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

## Lesson: Why the Ground Starts to Shake

You know an earthquake makes the ground shake suddenly. Underground rocks may stick while forces keep pushing or pulling them. The rocks slowly bend and store energy. When they suddenly slip along a crack, or break, they release energy. That energy travels through the ground as shaking. A slip can happen along a crack that is already there.

*(drawing: Stored energy is released when stuck rocks suddenly move.)*

**Example.** Rocks slip underground near a town. The sudden movement sends energy through the ground. People in the town feel shaking. Another town farther away may feel it too. Shaking usually weakens as it travels farther, though the kind of ground also affects it. The rock movement is the cause. The shaking people feel is an effect.

**Tip.** Ask two questions: What moved underground? What did people feel at the surface?

**Recap.** Earthquakes start when underground rocks suddenly move or break, sending shaking out through the ground around them.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [What Is an Earthquake](https://lightmysky.com/learn/science/what-is-an-earthquake-mt_e29VrLfmYt)

## Opens up

- [Plate Boundaries](https://lightmysky.com/learn/science/plate-boundaries-mt_-JnOhdei6F)
- [Ring of Fire](https://lightmysky.com/learn/science/ring-of-fire-mt_bhwf_rDXQL)
- [Measuring Earthquake Strength](https://lightmysky.com/learn/science/measuring-earthquake-strength-mt_mdZ3nBWChW)
- [Tsunamis](https://lightmysky.com/learn/science/tsunamis-mt_Wu-ftkzoiE)