1. What are the three types of volcanoes and what type of eruptions does each volcano have?

2. What do you know about volcanoes? And… Do you know of any famous volcanoes?

3. Volcanoes

4. The cause of it all… What do you think causes volcanoes to erupt? The shift in the Earth’s plates are what causes volcanoes to form and erupt.Earth’s plates As the plates join or separate some of the molten rock is exposed.

5. Where do volcanoes erupt? There are three places… Convergent plate boundaries – where two of Earth’s plates join together Divergent plate boundaries – where two of Earth’s plates move apart RING OF FIRE!!RING OF FIRE Hot spots – active areas below the earths crustHot spots

6. Volcanoes of the World

7. Structure of a Volcano Magma – the molten, or liquid-like, rock within the Earth Lava – magma that reaches Earth’s surface and is exposed to O 2 (two types of lava are Pahoehoe and Aa) Lava Viscosity~ Low viscosity = water high viscosity = maple syrup Vent – an opening through which molten (liquid-like) rock flows onto Earth’s surface Crater- the central opening at the top or summit of volcano. Volcanoes always have one central vent, but can also have several smaller side vents. (thickness), resistance of a liquid to flow.

8. Structure of a Volcano magma central vent side vent lava old layers of lava ash cloud Earth’s crust

9. Stages of a Volcano Magma chamber- the chamber below the volcano that stores the magma. Magma chamber- Without a magma chamber attached to the volcano it will be come extinct. With it, it is still considered active. If the volcano is still attached to its magma chamber but hasn’t erupted recently (100 years) it is considered to be dormant. It can still erupt at anytime!!

10. Types of Volcanoes There are three major types of volcanoes:major  Shield volcanoes  Composite volcanoes  Cinder cone volcanoes But there is also a fourth major volcanoe  Lava domes

11. Shield Volcanoes The flowing lava gives the volcano gently sloping sides. They have mild Eruptions that can occur several times. The lava tends to flow great distances. The magma rich in iron and magnesium and is very fluid (low viscosity).

12. Shield Volcanoes They have mild Eruptions that can occur several times. Mauna Loa and Kilaeua in Hawaii are examples of a shield volcanoes.

13. Mauna Loa (Shield Volcano)

14. Kilauea Caldera

15. Kilauea Crater

16. Composite Volcanoes They have much steeper slopes than shield volcanoes. They have alternating layers of lava and cinders. Eruptions can be flowing lava or explosions. Explosive eruptions come from the trapped gases and produce cinders and ash.

17. Composite Volcanoes The magma is rich in silica and much thicker than magma from a shield volcano. Gases get trapped inside this thicker magma. Mount Fuji in Japan and Mount St. Helens in Washington State in the US are examples of composite volcanoes.Mount St. Helens

18. Mt. Fuji (Composite Volcano) Stands over 13,000 ft. tall Surrounded by 5 lakes Last erupted in 1707-08.

19. Mount St. Helen’s Composite Volcano

20. Mount St. Helen’s Thermal Imaging

21. Mount St. Helen’s before and after eruption 19791980

22. Cinder Cone Volcanoes Cinder Cones have very steep sides! Usually only active for a short time and then become dormant (inactive). The magma inside a cinder cone volcano has large amounts of silica (63%) and gas trapped in it. The large amounts of hot ash and lava thrown out of the vent fall to the ground forming the cone shape that these volcanoes have.

23. Cinder Cone Volcanoes Violent and explosive eruptions because of all the gas trapped in the magma. Paricutin in Mexico and Mount Vesuvius in Italy are examples of a cinder cone volcanoes.

24. Paricutin Volcano (Cinder Cone) Grew over 5 stories in the first week Continued to erupt for 8 years reaching a height of over 1,300 ft.

25. Mount Vesuvius What do you notice in this picture?

26. Mount Vesuvius Thermal Imaging

27. Volcanic Dangers Pyroclastic flows Lahars Lava Volcanic ash Volcanic gas Which volcanic danger kills most people? Volcanic Ash

28. Pyroclastic flows Pyroclastic flows mixtures of hot gases, ash and rocks that travel about 450mi/hr down the sides of volcanoes. Dangerous because… The poisonous gases can be as hot as 1,000 degrees. They destroy anything in its path! They are rare and don’t happen in every eruption!

29. Pyroclastic Flows can even travel across water!

31. Ash and Pumice distribution

32. People of Pompeii

33. Animals of Pompeii

34. Lahars Lahars are mudflows formed by the mixing of volcanic particles and water. Dangerous because… Carry large boulders and logs down the side of a volcanoes. Can easily crush or shear off anything in its path!

35. Damage caused from Lahars

36. Lava Lava is molten rock expelled by a volcano during an eruption. Lava is a liquid at temperatures ranging from 1,300 °F to 2,200 °F. Although lava is about 100,000 times the viscosity of water, it can flow great distances before cooling and solidifying. Dangerous because… Lava can kill people, animals, and destroy property and even bury entire towns!

37. Types of Lava Pahoehoe lava is runny and fast moving (up to 50 km/h). Has high iron content. Pahoehoe Lava

38. Types of Lava Aa flows are chunky and slow moving lava flows Has a high silica content Aa Lava

39. Kona Lava Fields

40. Lava Tubes

41. Thurston’s Lava Tube