Effects of Volcanic Eruptions

1. Effects of Volcanic Eruptions

2. Volcanic Eruptions and Climate Change • Volcanic ash and gases spread throughout the atmosphere, they can block enough sunlight to cause global temperatures to drop. • Can cause average global temperatures to drop by as much as 0.5 degrees Celsius.

3. Different Types of Volcanoes • Volcanic eruptions can cause profound changes in climate. • There are three basic types of volcanoes which are: Shield, Cinder Cone, and Composite Volcanoes

4. Shield Volcanoes: are built of layers of lava released from repeated nonexplosive eruptions. • Lava is very runny • Spreads over a wide area • Gently sloping sides • Are enormous • Examples: Hawaii’s Mauna Kea (tallest on Earth) taller than Mount Everest.

5. Cinder Cone Volcanoes: are made of pyroclastic material usually produced from moderately explosive eruptions. • Form steep slopes • Small and usually erupt for only a short time • Occur in clusters, commonly on the sides of other volcanoes • Erode quickly because the pyroclastic material is not cemented together.

6. Composite Volcanoes: one of the most common types of volcanoes. • Form from explosive eruptions of pyroclastic material followed by quieter flows of lava • Broad bases and sides that get steeper toward the top. • Ex: Mount Hood, Mount Raineir, Mount Shasta, Mount St. Helens

7. Other Types of Volcanic Landforms • Such landforms as craters, calderas, and lava plateaus are also formed through volcanic activity. • Craters: • Around the central vent at the top of many volcanoes is a funnel-shaped pit.

8. Caldera: is a large, semicircular depression that forms when the chamber that supplies magma to a volcano partially empties and the chamber’s roof collapses. • Can appear similar to craters, but they are many time larger. • Yellowstone Park is made up of three large calderas that formed when volcanoes collapsed

9. Lava Plateaus: this a landform that results from repeated eruptions of lava spread over a large area. - Columbia River Plateau