1. Volcanoes

2. Volcano Eruption A volcano – is an opening in Earth’s crust through which molten rock, rock fragments, and hot gases erupt.

3. Magma Composed of silicon and oxygen compound Also contains gases, which expand as the magma rises Pressure builds up until the gases blacks out in a violent explosion

4. Magma Magma rises toward Earth’s surface if it is less dense than the surrounding rock. Magma chambers – holds magma until it can not hold any more and forces the magma out through an eruption.

5. Lava Lava – is magma that has reached Earth’s surface

6. Rock Fragments Ash – tiny rock fragments. Size of dust to rice grain. Can be carried long distances by wind (even all the way around Earth) Block – Can be the size of houses are solid pieces of rock. Fall quickly after eruption Cinders – bigger than ash, contain holes and tunnels left by escaping gases

7. Volcano Shapes and Sizes Shapes of Volcanoes depend on Magma Feeding 1.) Most erupt from openings in bowl-shaped pits called craters. 2.) Some erupt from long cracks in the ground

8. Shield Volcano Shaped like a broad, flat dome. Low silica (flows easily) Largest Volcano on Earth and one of the most active! Name: Mauna Loa Location: Hawaii Height: 10.5 miles most is underwater!

9. Cinder Cone A steep, cone-shaped hill formed by the eruption of cinders and other rock fragments that pile up around a single crater. One of the most famous volcanos Name: Parícutin Location: Mexico Height: 1.73miles

10. Composite Volcano A cone-shaped volcano built up of layers of lava and layers of rock fragments. High silica (flows slower and is pasty) Deadliest and most destructive volcanic event in the history of the US Name: Mount St. Helens Location: Washington, US Height: 1.58 miles

11. Monitoring Volcanoes Scientist monitor ▫Magma movement ▫Temperatures at openings, sprins, and lakes on volcanoes ▫Amount and type of gases given off ▫Rising temperatures ▫Changes in volcanic gases