Welcome to Science 10/21 Answer the following questions on your sheet of paper: 1. What is the title of Ch. 9 ? 2. What is the title of Ch. 9 Sec. 3? 3. What were the terms to learn for Ch. 9 Sec. 3? 4. In a short paragraph, describe the main idea of Ch. 9 Sec. 3.

Volcanoes and Plate Tectonics Section 1 What do you know?

Question of the Day Pictured below is a map of the world’s volcanoes and plate boundaries. What relationship between volcanoes and plate boundaries can be drawn from observing this map? Plate boundaries and volcanoes are found in close proximity. The movement of Earth’s plates creates volcanic mountains.

I. What is a volcano? Volcano-weak spot in the crust where molten material comes to the surface. Magma- a molten mixture of rock-forming substances, gases, and water from the mantle. Lava- magma that reaches Earth’s surface.

II. Where are most volcanoes found? Volcanic Belts- areas along plate boundaries where there are many volcanoes. Ring of Fire- major volcanic belt formed by the many volcanoes that rim the Pacific Ocean.

III. The Ring of Fire 75% of the world’s volcanoes are found in the Ring of Fire. 90% of the world’s EQs happens in the Ring of Fire. Why? The movements of the Pacific Plate.

IV. Volcanoes and Diverging Boundaries Volcanoes form at mid-ocean ridges and rift valleys, which are diverging plate boundaries. rift valley volcano

V. Volcanoes and Converging Boundaries These volcanoes form in 2 ways. Volcanoes can form when two oceanic plates collide or when an oceanic plate collides with a continental plate.

VI. Island Arc Volcano Tectonic Settings and Volcanic Activity Tectonic Settings and Volcanic Activity Form when 2 oceanic plates collide. The subducting plate melts to create magma. This magma rises up through the ocean floor to form volcanic islands.

VII.Continental Arc Volcano Tectonic Settings and Volcanic Activity Tectonic Settings and Volcanic Activity Form when an oceanic plate & a cont. plate collide. The oceanic plate is subducted under the cont. plate causing it to melt into magma. The magma rises through the continent to form volcanoes.

VIII. Hot Spot Volcanoes Hot spot- is an area where material from deep within the mantle rises and then melts forming magma. Hot spot can be near plate boundaries or in the middle of a plate.

IX. Hot Spot Tectonic Settings and Volcanic ActivityAnimation Tectonic Settings and Volcanic ActivityAnimation A volcano forms above a hot spot when magma erupts through the crust and reaches the surface. As the plate moves, new volcanoes will form over the Hot Spot.

TrackStar Activity TrackStar