8.2 Notes8.2 NotesTypes of Types of

VolcanoesVolcanoes

Key ConceptKey Concept: Tectonic : Tectonic Plate Motions can result in Plate Motions can result in volcanic activity at plate volcanic activity at plate

boundariesboundaries Which boundary has explosive volcanoes? Which boundary has explosive volcanoes?

Why?Why?

Which boundary has nonexplosive (quiet Which boundary has nonexplosive (quiet runny lava) volcanoes? Why?runny lava) volcanoes? Why?

What is the difference between magma What is the difference between magma and lava?and lava?

Lava Lava isis magma once it reaches Earth’s magma once it reaches Earth’s surfacesurface

4 types of lava:4 types of lava:1.1.AaAa2.2.PahoehoePahoehoe3.3.Pillow lavaPillow lava4.4.Blocky lavaBlocky lava

There are 3 types of There are 3 types of VolcanoesVolcanoes

Shield volcanoShield volcano Cinder cone volcanoCinder cone volcano Composite volcanoComposite volcano

Shield VolcanoesShield Volcanoes Usually form at hot spotsUsually form at hot spots Form from many layers of Form from many layers of nonexplosive nonexplosive

eruptions (quiet flows of lava)eruptions (quiet flows of lava) The lava is very runny, so it spreads over The lava is very runny, so it spreads over

a wide areaa wide area Gently sloping sides – not steepGently sloping sides – not steep Very large (meaning wide – not tall)Very large (meaning wide – not tall)

Cinder Cone VolcanoesCinder Cone Volcanoes Smallest type of volcanoSmallest type of volcano Most common type of volcanoMost common type of volcano Made of pyroclastic materialMade of pyroclastic material ModeratelyModerately explosive eruptions explosive eruptions Steep sidesSteep sides Wide summit craterWide summit crater Usually only erupts onceUsually only erupts once

Composite VolcanoesComposite Volcanoes Also known as a stratovolcanoAlso known as a stratovolcano Most recognizable of all volcanoesMost recognizable of all volcanoes Form from both explosive eruptions and Form from both explosive eruptions and

quieter flows of lavaquieter flows of lava Broad base and steep sidesBroad base and steep sides Erupts many times (every hundred years Erupts many times (every hundred years

or so)or so)