Volcano

• The Tick

• ETVolcanoonVenus

How Volcanoes Erupt

• “Gases dissolved in magma rush out, carrying the magma with them.”

• Magma Chamber

• Pipe (Sill – Dike)

• Vent

• Lava Flow – Pyroclastic Flow – Ash

• Crater

Generic Volcano

Strato Volcano

• Ash

• Lava

• Pyroclastic

Ash Eruptions

Characteristics of Magma

• It’s all about the Silica!

• Lots of Silica – thicker, stickier, lighter

• Not much Silica – smoother,darker

• Question – What kind is Hawaiian lava?

• Rhyolite

• High Silica

• Pumice

• High Silica

• Lots of gas

• Obsidian

• Mafic or Felsic?

• Oops, now in English, lots of Silicaor not much?

• (tricky!!!)

• Basalt

• Low Silica

• Dark

• Dense

• Pahoehoe

• High or lowsilica??

• ‘A‘a

• HighorlowSilica?

Slow cooling Basalts

• Columnar basalt – cools slow – this one is also a volcanicneck

Eroded Interiors

• Volcanic neck and Dike of a volcano

• The resthas erodedaway – Soyou can see the interior

Types of Volcanic Eruptions

• Quiet – Hawaiian Style– Pahoehoe – ‘A’a

• Explosive – Mt St Helens, Vesuvius

• http://pirate.shu.edu/~schoenma/volcanoes.htm

Stages

• Active

• Dormant

• Extinct