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1) Types of Volcanoes2) What is magma made of?1Composition (What something is made of)

Determined by the where it is formedgeologic settingDetermines what it is made fromMixture of SiO2, Fe, Mg and other elements.Amount of SiO2 in the magma determines:TypeViscosityGas release ability2What kind of rocks form?LavaMafic-DarkIntermediateFelsic-LightRock TypeBasaltAndesiteRhyoliteSiO2%45-5050-6060+ViscosityLowMediumHighTemperature

Lower-700 C

Medium

Higher-1600 C

Why is it called lava??? I thought it was magma

3Shield VolcanoesBroaderNot explosive Constant gas releaseWhy do you think it is not explosive (hmm)?High ViscosityFlows really well so you get broad short volcano

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6Cinder ConesSteepMore explosiveGases trappedViscosityWhat do you thinkHigher or lower thanShield?

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8StratovolcanoesSteepestlarge and explosiveSymmetricGases trappedTallestAt subduction zonesMt. Fuji, JapanMt. Pinatubo, PhilippinesMt. Rainier, WashingtonViscosity?

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10Guess What?!11Attention Check Time

1) If you want to make yourself a Hawaiian Shield Volcano at home what would be a good substitute for the viscosity of magma that it has?A) SyrupB) WaterC) MolassesD) there shouldnt be any magma2) Which volcanoes are the most explosive? 3) Why are they so explosive (what are 2 things they have in common)?4) Can you think of a way to make a volcano more explosive?12