How do tsunamis move? Caused by underwater earthquake, landslide, or volcanic eruption. The tectonic movement causes the ocean water to move about 500 miles an hour across the ocean. As they approach the coastline, they slow down and grow in height and energy.
What happens when it hits land? A tsunami produces a vacuum effect that sucks coastal water out into the ocean. Causes the sea water to retreat right before it strikes land. Occurs about 5 minutes before it hits this is a warning sign to leave the beach.
https://www.youtube.com/watch?v=oWzdgBNfhQU
What are volcanoes? Volcanoes are a place on Earth’s surface where hot, molten rock (called magma) breaks through.
What are volcanoes? Active volcanoes erupt or show seismic (earthquake) activity. Dormant volcanoes have not erupted for a long time, but could erupt again one day. Extinct volcanoes will never erupt again.
Why do volcanoes erupt? Lower density of magma relative to surrounding rocks cause it to rise (like air bubbles in syrup). The gas bubbles in the magma dissolve and create large amounts of pressure. This pressure brings magma to the surface and forces it into the air.
Types of Volcanoes
Types of Volcanoes Cinder Cone Volcano Small volcanoes (< 300 m tall) with no layers. Steep conical hill of volcanic debris and small crater on top. Explosive eruption.
Types of Volcanoes Shield Volcanoes Large (10s of kms wide) volcanoes built mostly from fluid lava vents. Quiet eruptions Looks like a warriors shield from the sky. These types of volcanoes make up the Islands of Hawaii
Types of Volcanoes Composite Volcano (Stratovolcano) Large (1-10 km wide) Made of layers of solid lava mixed with layers of rocks. Explosive eruption
What is a hot spot? Mantle plumes are areas of hot upwell mantle. A hot spot develops over a mantle plume as magma rises though the lithospheric plate producing a volcano. As the plates move, oceanic volcanoes move away from the hot spot, cool and subside, and produce island. Eventually they become extinct volcanoes.
What is an example of hot spot? The Islands of Hawaii were created from a hot spot within the Pacific Plate. This hot spot created 3,750 miles of volcanic chain of islands.