Supervolcano eruptions are extremely rare in Earths history. Its a good thing because they are unimaginably large. A supervolcano must erupt more than 1,000 cubic km (240 cubic miles) of material, compared with 1.2 km3 for Mount St. Helens or 25 km3 for Mount Pinatubo, a large eruption in the Philippines in 1991. Not surprisingly, supervolcanoes are the most dangerous type of volcano.
The exact cause of supervolcano eruptions is still debated. However, scientists think that a very large magma chamber erupts entirely in one catastrophic explosion. This creates a huge hole or caldera into which the surface collapses (Figure 1.1). The caldera at Santorini in Greece is so large that it can only be seen by satellite.
The largest supervolcano in North America is beneath Yellowstone National Park in Wyoming. Yellowstone sits above a hotspot that has erupted catastrophically three times: 2.1 million, 1.3 million, and 640,000 years ago. Yellowstone has produced many smaller (but still enormous) eruptions more recently (Figure 1.2). Fortunately, current activity at Yellowstone is limited to the regions famous geysers. Click image to the left or use the URL below. URL: The Yellowstone hotspot has produced enormous felsic eruptions. The Yellowstone caldera collapsed in the most recent super eruption.
supervolcano eruptions and life on earth
A supervolcano could change life on Earth as we know it. Ash could block sunlight so much that photosynthesis would be reduced and global temperatures would plummet. Volcanic eruptions could have contributed to some of the mass extinctions in our planets history. No one knows when the next super eruption will be. Interesting volcano videos are seen on National Geographic Videos, Environment Video, Natural Disasters, Earth- quakes: One interesting one is Mammoth Mountain, which explores Hot Creek and the volcanic area it is a part of in California. Click image to the left or use the URL below. URL:
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this is the largest supervolcano found in north america.
a) mt. pinatubo b) mount st. helen c) mount shasta --> d) yellowstone
a circular shaped hole into which a volcano collapses during an eruption:
--> a) caldera b) volcanic neck c) batholith d) plateau
a) is usually mafic in composition. --> b) ejects an extremely large magma chamber of material in one huge explosion. c) has lava and ash layers like a composite volcano. d) all of these.
this famous geyser can be found at yellowstone national park.
a) old mcdonald --> b) old faithful c) old woman d) el tatio
supervolcanoes can cause mass extinctions.
--> a) true b) false
eruptions of hotspots beneath continents are extremely explosive because
a) the eruptions occur frequently. b) the eruptions release enormous amounts of felsic lava. --> c) a massive plume massive enough to penetrate continental crust is very hot. d) both a and c.
supervolcano eruptions happen somewhere on earth about every 1,000 years.
a) true --> b) false
a supervolcano can change life on earth by
--> a) blocking sunlight so that photosynthesis stops or slows. b) raising temperature worldwide for years. c) covering the entire surface of a continent with lava flows. d) all of these.
where do supervolcanoes usually form?
a) convergent boundary b) divergent boundary --> c) continental hotspots d) all of these
yellowstone is a supervolcano that has had three massive eruptions.
--> a) true b) false
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