Volcanic eruptions can have immediate and long-term effects on the surrounding land, air, and water. Immediate effects include lava flows, volcanic ash, mudflows, pyroclastic flows, landslides, and steam explosions. Long-term effects involve continued mudflows over time, crater collapse, hardened lava forming new rock layers, and ash helping to build new landscapes. Eruptions release gases like sulfur dioxide and carbon dioxide into the air, and can produce acid rain by releasing acids. They also affect water by creating hot springs, geysers, fumaroles, and deep sea vents.

1. Volcanoes affect Earth’s land, air, and water Pages 156-162 (section B)

2. Immediate Effect of Volcanic Eruptions Lava Flows Most lava flows move slowly enough that people can move away and not be hurt. Lava flow can knock down, cover, or burn nearly everything in its path

3. Immediate Effect of Volcanic Eruptions Volcanic Ash Volcanic ash is heavy because it is made up tiny pieces of rock The weight of volcanic ash can cause the roofs to collapse Volcanic ash can clog machinery, including cars and airplanes Can suffocate animals and people

4. Immediate Effect of Volcanic Eruptions Mudflows Landslides that occur when loose rocks and soil and rocks are mixed with water Heat from an eruption can melt any ice and snow very quickly Also form as ash mixes into rivers Fast flowing mudflows have buried entire towns

5. Immediate Effect of Volcanic Eruptions Pyroclastic flows Tend to rush downhill, following valleys, BUT can have enough force to climb up hills Can leave a thick layer of volcanic rock fragments as it passes through an area The most dangerous type of eruptions: in 1902 almost 30,000 people were killed within a few minutes

6. Immediate Effect of Volcanic Eruptions Landslides Part of a volcano can collapse and start a landslide A landslide can cause a tsunami if a large amount of material falls into the ocean

7. Immediate Effect of Volcanic Eruptions Steam explosions Relatively uncommon, but can be devastating They occur when magma comes near water or into contact with it. A steam explosion may have caused the destruction of Krakatau, in 1883

8. Long-term Destructive Effects of Volcanic Eruptions Mudflows can continue to develop over time when rain mixes with the rock fragments thrown out Water can fill in the crater of the volcano. The upper part of the crater is weak and easily collapse When the lava cools, it forms a layer of hard rock

9. Long-term Positive Effects of Volcanic Eruptions After many years, the hardened lava can break down and it creates rich soil Highly productive farmland surrounds some active volcanoes Over time, repeated volcanic eruptions can build a magnificent landscape of mountains and valleys. People chose to live in these areas for the natural beauty, many tourist visit for the areas as well.

10. Volcanic Gases and Ash affect the Air Sulfur dioxide, which smells like rotten eggs, is a gas common in volcanic eruptions Carbon dioxide, which is odorless and colorless, can be fatal to humans Gases from the volcano can help to carry ash 100’s of miles

11. Acid Rain Acid Rain - rain that contains large amounts of acid Volcanic eruptions are a source of acid rain Human activity is the most common source of acid rain

12. Volcanic Activity affects Water Hot springs form as magma heats water In most hot spring, the water flows out in calm pool Geyser- a type of hot spring that shoots water into the air.

13. Volcanic Activity affects Water Fumarole- similar to a hot spring, instead of water a fumerole releases steam and other gases

14. Volcanic Activity affects Water Deep- Sea Vent- hot spring that form at spreading centers in the ocean.