Do now How are volcanoes and earthquakes related? Can you name some famous volcanoes or areas of the world where there was a big eruption?
Earthquakes vs. volcanoes Earthquakes caused by the movement of plates against each other. Volcanoes caused by the movement of magma
Where? Volcanoes also form along the tectonic plate boundaries and at hot spots.
Magma- Less Dense Iceland
Volcanoes also form along convergent plate boundaries Volcanic Mountain Ranges Volcanic Island Arcs
Mt vesuvius-italy Pompeii
Hot spots
Famous hot spot volcano Mauna loa Famous hot spot volcano
Vent Parts of a volcano Crater Pipe Magma Chamber Lava Flow Ash, Dust, Rock Lava Flow Vent Pipe Rock and Ash Lavers Magma Chamber
Do now Where do volcanoes occur? Name examples for each area where volcanoes occur.
Types of eruptions Why are some eruptions quiet and others explosive? Trapped Gases Magma Composition
Trapped gases Water vapor and carbon dioxide trapped in magma build up. Less pressure as the magma rises. Quiet eruption- Gas escapes easily from magma Explosive eruption-Gas builds to high pressures
Types of magma- Low amounts of Silica Quiet Eruptions-Magma is fluid Examples-Hots spots (Hawaii) and divergent boundaries (Iceland) High amounts of Silica Explosive Eruptions-Magma is thick Examples-Mt. St Helens (Washington State)
Mauna Loa- Hawaii-QUIET Mt. St. Helens- Washington State-EXPLOSIVE Explosive vs quiet Mauna Loa- Hawaii-QUIET Mt. St. Helens- Washington State-EXPLOSIVE
Forms of volcanoes Shield Cinder Cone Composite Depends on whether the volcano is Quiet or Explosive
Shield volcano Broad volcanoes with gently sloping sides Low silica magma Quiet Eruptions Mauna Loa-Hawaiian Islands
Cinder cone volcano -Steep volcanoes build up by ash that settles on the slopes -High Silica Magma -Explosive Eruptions -Paricutin-Mexico
Composite volcano Tall, conical volcanoes formed by different layers of ash, lava, dust and rock High silica magma Quiet and explosive eruptions Mt Vesuvius-Italy Mt St. Helens
Do now What are the three types of volcanoes and name an example of each?
Volcanic rock features Igneous rock= cooling of lava and magma Batholith=magma cools underground. Does not erupt.
-Cooled magma exposed by erosion batholiths -Cooled magma exposed by erosion
Dikes and sills Sills-Magma cooled along horizontal cracks in the rock Dikes-Magma cooled along vertical cracks in the rock Sills-Magma cooled along horizontal cracks in the rock
Necks and caldera Neck-Hardened magma within a volcanic vent. Caldera-Volcano collapses onto itself.