Overview of Volcanoes Gentle Eruption Lava Flows Violent

Overview of Volcanoes Gentle Eruption = Lava Flows Violent Eruptions = Pyroclastic Flows

Types of Volcanoes Compare the composition and size of a shield volcano and a Composite Cone

Shield Volcano - Big Island of Hawaii

Lava Fountain What is the viscosity of this lava? It’s volatile content? What’s its chemical composition?

Lava River Is this behavior gentle or violent?

Lava flow cause localized damage.

When this lava cools It forms basalt Two types of flows Aa Pahoehoe

Composite Cone - Philippines

Anatomy of a Composite Cone

Composite Cones Erupt Violently

Composite Cones Also Erupt Gently What is the viscosity of this lava? It’s volatile content? What’s its chemical composition? When this lava cools it forms Andesite

Volcanic Dome - Oregon

Volcanic Domes Fail Suddenly

SOME QUESTIONS What is the viscosity of this lava? It’s volatile content? What’s its chemical composition? When this lava cools it forms Rhyolite

Volcanic Hazards • Lava Flows • Volatiles • Pyroclastic Explosions • Lahars • Tephra

Volcanic Hazards - Lava Flows

Volcanic Hazards - Volatilities - VOG

Volcanic Hazards - Volatilities Carbon Dioxide Asphyxiation

Volcanic Hazards Volatilities - Laze

Volcanic Hazards - Pyroclastic Explosion Nuee Ardente

Volcanic Hazards - Lahar

Lahars are caused by either: Intense rainfall around a volcanic summit Suddenly melting snows and glaciers

Volcanic Hazards Tephra

Tephra or Volcanic Ash is thickest closest to a volcanic eruption