Day 30: Volcanism Objective: Warm-Up You will use the theory of plate tectonics to explain the changes that occur in the earth’s surface. (Volcanism) KWL Chart about volcanoes (3 for each column) I will call on 9 people to fill in the chart on the IWB so be ready!

REVIEW PLATE TECTONICS Day 30: Volcanism Objective: Warm-Up You will use the theory of plate tectonics to explain the changes that occur in the earth’s surface. (Volcanism) REVIEW PLATE TECTONICS

(4 Sentences OR 8 Bullets) Volcanoes 101 After the video clip, you will be asked to SUMMARIZE the video clip. Be sure to include the main points. (4 Sentences OR 8 Bullets)

Volcano Terminology (Volcanism) Vulcan – Roman god of fire and metalworking. Lived under mount Etna . Mountains which spit fire were known as volcanoes.  Volcano – Landform that develops on the surface of the earth where magma and gases erupt through a vent.  Magma – molten rock. Intrusive (inside the earth)  

Volcano Terminology (Volcanism) Lava – molten rock. Extrusive (outside, on the surface)  Volcanology – the study of volcanoes.  Volcanologist – a scientist who studies volcanoes

How do Volcanoes Form? Volcanoes form two ways – Plate tectonics and Hot spots.

Plate tectonics – convergent plate boundaries (colliding) ocean / continental –volcano ocean / ocean – island arc The ocean plate in both cases is subducted beneath the other plate. The ocean plate is melted. Forms magma. The magma rises. The rising magma puts pressure on the surface causing it to dome upward, forming a volcano. The volcano erupts if the pressure continues. 

Plate tectonics – convergent plate boundaries (colliding) ocean / continental –volcano ocean / ocean – island arc Subduction Zone

Hot Spots An area in the mantle where magma is created and continuously rises to the surface. It is believed that a hot spot is responsible for the creation of the Hawaiian Islands.

WHERE ARE VOLCANOES FOUND:  Volcanoes are usually found near convergent plate boundaries.   Ring of fire – An area which encircles the Pacific Ocean where there is a great deal of volcanic activity. Fissure – a crack in the Earth’s surface where lava flows out from. Similar to a volcano only the crust does not dome upward.

Ring of Fire- Pacific Plate Think Back: What is happening to the Pacific plate? Why?

Fissure

Closure What types of plate boundaries result in the formation of volcanoes? The Pacific plate is shrinking because it is being subducted on all sides. What is the boundary’s nickname?

Objective You will use the composition, size and eruption type of volcanoes in order to classify volcanoes Match the following terms: Vulcan A. molten rock intrusively Volcanologist B. molten rock extrusively Volcanology C. Roman god of fire Lava D. Person who studies volcanoes Magma E. The study of volcanoes

Types of Volcanoes

Viscosity The resistance to flow. Substances which do not flow easily have a high viscosity. (HONEY or MOLASSAS) Substances which flow easily have a low viscosity.

Types of Eruptions: Silica- high viscosity- violent eruption Violent Eruptions-Explosive Quiet Eruptions Silica- high viscosity- violent eruption Water- low viscosity- quiet eruption

Volcanic Activity: Active Volcanoes which have erupted during recent times.

Volcanic Activity: Dormant Volcanoes that have not erupted in recent times but show some signs of volcanic activity.

Volcanic Activity: Extinct Volcanoes which have not erupted during recorded history and do no seem capable of erupting.

VOLCANIC FEATURES

Pipe or Vent: Magma Chamber Vertical tunnels extending from the magma chamber to the surface of the earth. The channel or pathway the lava flows during an eruption. Area below the surface where magma collects

Plume Pyroclastic Rock A large volcanic dust cloud which occurs during a violent eruption. Contains pyroclastic rock and gases. Any rock formed when lava or solid rock erupts explosively Types of Pyroclastic Material: Fine ash Coarse ash Cinders Volcanic bombs

Ash Flows Glowing cloud a mixture of volcanic ash, gases, and pyroclastic particles that flows rapidly along the earth’s surface at speeds up to 300 km/hr. EXTREMELY HOT!

Caldera A large circular hole that forms when part of the volcano collapses into the magma chamber after an eruption

Closure 1. How are cinder cone volcanoes formed? What is its explosion type? 2. Provide some of the characteristics of a shield volcano? What is its explosion type? 3. Why does a composite volcano have alternating layers of ash and lava? What is its explosion type?