1. Plate Tectonic features
Volcanoes
Plate Tectonic features

2. Definition
Vent in Earth’s surface out of which lava, debris, and gases are released
Magma and gases build up, resulting in explosions
i. Can be explosive: lava, rock, ashes
ii. Less gas means less explosive but with more oozing lava

4. B. Magma varies
i. Runny
ii. Thick and sludge-like

5. Terms Magma chamber: large underground pool of magma
Lava: magma, once it reaches the surface
Crater: bowl-shaped basin in the top of the volcano
Vent: central tube which magma travels through

6. V. Volcanic bombs: larger material thrown out by the force of an explosive eruption
VI. Ash, gas, steam: material thrown out by volcanoes

7. Image
Image we associate with volcanoes is a result of volcanic activity
Mountain-like mounds formed from the hardened matter spewed during explosions
i. Can occur from a few weeks to millions of years

8. Danger Level Flows of lava can reach 2000 degrees fahrenheit
Burns all in its path, including entire towns
Can include boulders of hardening lava
Mud caused by rapidly melting snow can strip land of its nutrients and topsoil

9. D. Ash and gases can burn lungs and can be toxic
II. In the past 300 years, the estimate is that over 260,000 have died from volcanic activity and its aftermath

10. Activity Most common along plate boundaries
90% of all volcanoes are found along the Ring of Fire along the edges of the Pacific Ocean
II. Of all volcanoes on Earth, about 1900 are said to be active
Show some level of activity and are likely to explode again

11. III. Dormant volcanoes are not currently active but are likely to be so at some time in the future
IV. Extinct volcanoes are those expected never to be active again

12. Types of Volcanoes Composite Characteristics:
i. Steep sides and cone-shaped
ii. Made of layers of ash and lava
iii. Lava is sticky, not flowing very far
iv. Eruptions tend to be often and gentle
Example: Mount Etna in Italy

14. II. Shield
Characteristics:
i. Gently sloping sides
ii. Runny lava covers a wide area
iii. Gases escape easily here
iv. Eruptions tend to be pyroclastic
Example: Mauna Loa in Hawaii

15. C. Pyroclastic:
i. Mixture of hot steam, ash, rock, and dust
ii. Can roll down sides of volcanoes extremely quickly

17. Supervolcanoes What makes it “super”
Massive scale (at least 1000km³ of debris, while normal volcanoes spew 1km³ of debris)
Forms a depression called a caldera rather than a cone shape
Often surrounded by a ridge of higher land

18. D. Erupts less frequently - hundreds of thousands of years between eruptions
II. Example: Yellowstone
At a volcanic hotspot

19. Why Studied To predict future eruptions
To gather info about Earth’s surface and interior
Soil near volcanoes is very fertile due to minerals that act as fertilizer to plants
i. Igneous rock, that formed from hardened magma: basalt contains iron and rhyolite contains silica

20. B. The slower the magma cools, the larger the crystals in the igneous rock

21. Tops of underwater mountains
Islands
Tops of underwater mountains