Volcanoes and Tectonic Plates

Study Notes

Volcanoes and Tectonic Plates

What are Volcanoes?

A landform that occurs when magma from the Earth's interior rises to the surface, resulting in eruptions of molten rock, ash, and gas
Can be found on land and under the ocean

Types of Volcanoes

Shield Volcanoes: gently sloping, rounded volcanoes with a broad base and gentle slopes
- Formed by the eruption of fluid lava flows
- Examples: Hawaiian Islands, Iceland
Stratovolcanoes: tall, conical volcanoes with steep slopes
- Formed by a combination of lava flows, ash, and other pyroclastic material
- Examples: Mount St. Helens, Mount Fuji
Cinder Cones: small, steep-sided volcanoes formed from accumulated ash and cinder
- Examples: Paricutin volcano in Mexico

What are Tectonic Plates?

Large, rigid slabs of the Earth's lithosphere (outer layer) that fit together like a jigsaw puzzle
In constant motion, sliding over the more fluid asthenosphere (upper mantle) below

Plate Boundaries

Divergent Boundaries: where plates move apart, new crust is formed
- Example: Mid-Atlantic Ridge
Convergent Boundaries: where plates collide, crust is destroyed or thickened
- Example: Andean mountain building
Transform Boundaries: where plates slide past each other horizontally
- Example: San Andreas Fault

Volcanoes and Plate Tectonics

Most volcanoes are located at plate boundaries, where the Earth's crust is being stretched or compressed
The movement of tectonic plates is the driving force behind volcanic activity
Volcanic arcs form when an oceanic plate is being subducted beneath a continental plate
- Example: Andes mountain range

Hotspots

Areas of volcanic activity that are not located at plate boundaries
Thought to be caused by mantle plumes, upwellings of hot rock that rise from the Earth's core-mantle boundary
Example: Hawaiian Islands

Description

Learn about the different types of volcanoes, including shield, stratovolcanoes, and cinder cones. Understand how volcanoes are formed and their relationship with tectonic plates. Discover how plate boundaries and hotspots affect volcanic activity.