The hazards of volcanoes- Pyroclastic flows- hot, fast (200km/h)Contain poisonous gas, rocks and sand- Ash cloudsSuffocation , buildings collapse due to weight- Volcanic bombsChunks of rock fired out, range several km- LavaBuildings and crops hit, people mostly escape- Poisonous gasCarbon monoxide, sulphurous gases- acid rain
Locations... Even Ancient ones in Glencoe, Scotland &USA – Yellowstone,Wyoming; Scafell in Lake District!Long Valley, California; Siberia, RussiaLongridge, Oregon Kyushu, Japan Toba, Sumatra, Indonesia New Zealand
Recipe for a supervolcano Ingredients - A hot spotMethod1) Allow hot spot to spew magma2) Let the magma build up underneath the surface3) Ensure that the magma builds up to the point where the rock around begins to melt, creating a large chamber4) Wait until the pressure builds
Recipe for a supervolcano Ingredients - A hot spotYou know you have followedthe direcions carefully ifYour supervolcano blows thewhole surface of the magmachamber away, leaving acaldera (see photo)
Cause/Formation of a supervolcano... Yellowstone is caused by an undergroundHOTSPOT not plate margins...
Supervolcanoes• Erupts at least 1000km3 of magma- NOT characteristic cone shaped- depressions in the ground (very hard to spot)• last supervolcano to erupt was 74000 years ago in Indonesia a gigantic volcanic eruption shook the earth• The ash was thrown out 3000km, created global cooling and created a crater larger than the city of London (now Lake Toba)
Supervolcano vs volcanoWould eject more than • Mount St. Helens in1,000 cubic kilometers 1980 erupted less than(240 cubic miles) of one cubic kilometre ofpumice and ash in a single magmaevent
YellowstoneActive SupervolcanoOver 3 million people visit the park every yearhot spot beneath Yellowstone• 2 million years ago this hotspot settled under Yellowstone• 2.1 bil years ago- Caldera explosion= 80km mountains gone