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