Volcanoes. Volcanic landforms Effusive eruptions (gentle flows, lots of lava) cinder cones shield...
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Transcript of Volcanoes. Volcanic landforms Effusive eruptions (gentle flows, lots of lava) cinder cones shield...
Volcanic landforms
Effusive eruptions (gentle flows, lots of lava)• cinder cones • shield volcanoes • plateau basalts
Explosive eruptions (viscous lava, trapped gases)• composite volcanoes• calderas
Cinder coneBig Cinder Butte, Craters of the Moon, Idaho
- forms small hills, less than 450 m high
- black scoria rock with air bubbles
Shield volcanoMauna Loa, Hawaii
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Low viscosity magmaGases readily escape From this magma
Effusive eruptions
Volcanic hazards and effects
• hot ash (pyroclastics)• steam and gas explosions• lava flows• poisonous gases (carbon dioxide, sulfuric acid)• landslides• tree blowdowns• lahars (steam-melted ice and snow cause flooding
and large mudflows)• increase in atmospheric dust (decreased global
temperatures)
Volcanic benefits
• new fertile soils
- Hawaii, Philippines
• geothermal energy
- Iceland, Italy, New Zealand
• new real estate
- Iceland, Japan, Hawaii