--- title: "Plate Boundaries" description: "Explain how plate boundaries cause earthquakes and volcanoes: plates pushing together, pulling apart, or sliding past each other create the forces that trigger these events, and mountains form where p" canonical: https://lightmysky.com/learn/science/plate-boundaries-mt_-JnOhdei6F source: https://lightmysky.com/learn/science/plate-boundaries-mt_-JnOhdei6F.md retrieved: 2026-10-19 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Plate Boundaries Explain how plate boundaries cause earthquakes and volcanoes: plates pushing together, pulling apart, or sliding past each other create the forces that trigger these events, and mountains form where plates collide Subject: Science · Area: Volcanoes & Earthquakes · Ages 9 to 11 Page: https://lightmysky.com/learn/science/plate-boundaries-mt_-JnOhdei6F ## Ready when they can - Describe three types of plate boundary movement: convergent, divergent, and transform - Explain that earthquakes occur when plates grind or collide at boundaries - Explain that volcanoes form where plates pull apart or one slides under another, allowing magma to rise ## Lesson: Where plates meet: boundaries that shake and build You know Earth's outer shell has huge, slow-moving plates. Where two meet is a boundary. At a convergent boundary, plates push together. Two colliding continents can squeeze and thicken the crust, raising tall mountains. At a divergent boundary, plates pull apart. At a transform boundary, plates slide past each other sideways. Sideways grinding and sudden jolts point to a transform boundary. Earthquakes can happen where plates grind or collide. Parts of their edges may stick while the plates keep moving. Stress builds as the moving plates push or pull the stuck rock. When the rock suddenly slips, stored energy spreads as earthquake waves. At some convergent boundaries, one plate sinks under another. This is subduction. As the sinking plate heats up, it releases water. The water helps some hot mantle rock above it melt into magma. Magma can rise and feed volcanoes. The usual cause is melting above the sinking plate, not the whole plate melting. Volcanoes can also form where plates pull apart, so they occur at both kinds of boundary. At a divergent boundary, plates pull apart. Hot mantle rock rises and partly melts as pressure drops. The magma can cool into new crust, often under the ocean. At a transform boundary, sideways movement can cause earthquakes. The sliding itself does not usually produce magma. **Example.** The San Andreas Fault in California is a transform boundary. Some parts stick as the plates move past each other. Stress builds until the stuck rock slips, sending out earthquake waves. Other parts creep more steadily. **Tip.** Push together can raise mountains or feed volcanoes. Pull apart can grow new crust. Slide past can cause earthquakes. Earthquakes occur at all three kinds of boundary. **Recap.** Plate movement helps explain mountains, volcanoes, and earthquakes. Water from a sinking plate helps mantle rock above it melt. ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Why Earthquakes Happen](https://lightmysky.com/learn/science/why-earthquakes-happen-mt_NVr4AhsvIq) - [Tectonic Plates](https://lightmysky.com/learn/science/tectonic-plates-mt_XrvPx5kUfO) ## Opens up - [How Tectonic Plates Move](https://lightmysky.com/learn/science/how-tectonic-plates-move-mt_gv_uoHkdjR) - [Plate Tectonics: the Evidence and the Engine](https://lightmysky.com/learn/science/plate-tectonics-the-evidence-and-the-engine-mt_K4hJlyOZ7p) - [Famous Eruptions & Pangaea](https://lightmysky.com/learn/science/famous-eruptions-and-pangaea-mt_rML9unnd9x) - [Eruption Types & Volcano Shape](https://lightmysky.com/learn/science/eruption-types-and-volcano-shape-mt_W4j7T_PnGH) - [Earthquake-Resistant Design](https://lightmysky.com/learn/science/earthquake-resistant-design-mt_yDZbQODIwp) - [Monitoring Volcanoes](https://lightmysky.com/learn/science/monitoring-volcanoes-mt_ZRoQVXf_aD)