1. Volcanoes Affect Earth
3-3 Notes
Volcanoes Affect Earth

2. Which volcano do you think is the most dangerous? Why?
Think About…
Which volcano do you think is the most dangerous? Why?
Mauna Loa – Shield Volcano
Mt. Shasta – Composite Volcano

3. Lava Flows Immediate Effects
Slow enough that people are able to get away
Knock down, cover, or burn everything in its path

4. Ash Immediate Effects Heavy (it is made of rock!) Makes roads slippery
Suffocates living things

5. Mudflows Immediate Effects
Snow and ice on the volcano melt, mixing with ash and soil and sliding downhill.
Entire towns can be buried by volcanic mudflows.

6. Pyroclastic Flows Immediate Effects
Can knock down, burn, and bury anything in its path.

7. Landslides Immediate Effects
Part of a volcano collapses and rock and soil slide downhill.
This can even cause a tsunami!

8. Steam Explosions Immediate Effects
When magma comes into contact with water.

9. A volcano can have effects that last for many years.
Long-Term Effects
A volcano can have effects that last for many years.

10. Long-Term Effects
Mudflows are a risk for years after an eruption as rainwater mixes with deposits of ash.

11. Volcanoes can also have positive effects

12. Positive Effects
When lava cools and breaks down, it forms rich, fertile soil that is excellent for growing plants and crops.

13. Positive Effects
Repeated eruptions can build landscapes of mountains and valleys with a lot of plant growth.
This makes some volcanic regions highly desirable places to live and visit (e.g. Hawaii).

14. Air
Volcanoes release gases into the air, mainly water vapor and carbon dioxide.

15. Volcanoes release gases before, during, and after eruptions.
Air
Volcanoes release gases before, during, and after eruptions.

16. Volcanoes release small amounts of other gases.
Air
Volcanoes release small amounts of other gases.
Some of these gases contain sulfur, which gives off an unpleasant odor.

17. Hydrogen sulfide gas smells like rotten eggs.
Air
Hydrogen sulfide gas smells like rotten eggs.

18. Sulfur dioxide is the compound you smell when you strike a match.
Air
Sulfur dioxide is the compound you smell when you strike a match.

19. Air
Many gases released by volcanoes are dangerous because they make breathing difficult or can damage the lungs of people and animals.

20. Carbon dioxide can be deadly in large quantities.
Air
Carbon dioxide can be deadly in large quantities.
It is especially dangerous because it has no color or odor.

21. Air
In West Africa, a lake with a volcano under it built up toxic levels of carbon dioxide.
The carbon dioxide was released at once, killing 1700 people in

22. Air
Some volcanic gases (e.g. sulfur dioxide) form acids when they mix with water in the air.
These acids then fall back to Earth as rain, snow, or sleet, which can damage forests and kill wildlife.

23. Air
Large amounts of volcanic gases can change the weather around the entire world.

24. Air
Ash clouds can travel thousands of miles, sometimes blocking out so much sunlight that global temperatures drop.

25. Air
The eruption of Mt. Pinatubo in caused global temperatures to drop in both and 1993.

26. Air
The ash clouds released by Mt. St. Helens in caused so much ash to be released that some cities had to turn their streetlights on during the day!

27. Volcanoes heat water on the surface or in the crust near the volcano.

28. Hot Springs, Geysers, Fumaroles
Hot Springs – places where heated water flows to Earth’s surface.

29. Hot Springs, Geysers, and Fumaroles
Geyser – a type of hot spring in which water shoots into the air through a narrow channel.

30. Hot Springs, Geysers, and Fumaroles
Fumarole – similar to a hot spring, but steam and other gases are released instead of liquid water.

31. Deep-Sea Vents
Deep-sea vents are underwater hot springs that form at spreading centers in the ocean.

32. The hot water has a lot of dissolved minerals and gases in it.
Deep-Sea Vents
The hot water has a lot of dissolved minerals and gases in it.

33. Deep-Sea Vents
The water released by deep-sea vents is often black because of the dissolved minerals.

34. As the hot water cools, the minerals harden into chimneys of rock.
Deep-Sea Vents
As the hot water cools, the minerals harden into chimneys of rock.

35. Deep-Sea Vents
Deep-sea vents create interesting ecosystems with many unusual organisms, including one-celled organisms that do not rely on sunlight.

36. Vent Octopus

37. Yeti Crab

38. Giant Tube Worm

39. Review
1. What are some of the effects of volcanic eruptions on Earth’s atmosphere?
A. An increase in the amount of sunlight that reaches Earth and a decrease in acid rain.
B. A decrease in the amount of sunlight that reaches Earth and an increase in Earth’s temperature.
C. An increase in acid rain and an increase in Earth’s temperature.
D. An increase in acid rain and a decrease in Earth’s temperature.

40. Review
2. What does a fumarole release?
Hot, liquid water
Cold, liquid water
Steam and other gases
Magma