Quartz
July 14, 2006, 11:47pm
1
The BBC has had a volcano week. One of the types of volcanoes mentioned was the supervolcano, specifically the Yellowstone one, with dire warnings of what would happen if / when it blows. But how do they know it’s going to do a Krakatoa and not be like the Hawaiian volcanoes with a ‘gentle’ but sustained outpouring of lava?
Squink
July 14, 2006, 11:56pm
2
Three extraordinarily large explosive eruptions in the past 2.1 million years each created a giant caldera within or west of Yellowstone National Park with the spread of enormous volumes of hot, fragmented volcanic rocks as pyroclastic flows over vast areas within times as short as a few days or weeks.
The long-term nature of volcanism in this part of North America suggests that more eruptions will occur as the Yellowstone National Park continues to evolve. The most recent series of eruptions, 160,000 to 70,000 years ago, extruded more than 20 thick rhyolite lava flows and domes, most of them within the youngest caldera. Other postcaldera lavas are basalts, erupted around the margins of the rhyolitic calderas. Based on Yellowstone’s history, the next eruptions are likely to expel lavas, which might be either rhyolites or basalts, possibly accompanied by moderate explosive activity. Far less likely would be another enormous outpouring of material that could lead to a fourth caldera.
Basically, because that’s what supervolcanoes do. Scientific American had an article last month that goes into some detail about what we know here.
Quartz
July 15, 2006, 8:41am
4
Ooh! Excellent.
I was particularly interested to see that it took the Earth at most 6 years to fully recover from Toba.