I also enjoy engaging conversations like this, concerning Earth's geology. I was never too concerned about it until preparations leading up to my Grand Canyon trips. Now I read an absorb everything I can get my hands on, about it. I will definitely be reading this book.

I do see a few items that are contradictory to things that I have read, such as the Yellowstone eruptions causing mass human extinctions 70,000 years ago. The last known supervolcanic eruption was 640,000 years ago. There was an eruption 70,000 years ago but it was not an explosive eruption. It was merely a lava flow.

Quote:
The loosely defined term 'supervolcano' has been used to describe volcanic fields that produce exceptionally large volcanic eruptions. Thus defined, the Yellowstone Supervolcano is the volcanic field which produced the latest three supereruptions from the Yellowstone hotspot. The three super eruptions occurred 2.1 million, 1.3 million, and 640,000 years ago; forming the Island Park Caldera, the Henry's Fork Caldera, and Yellowstone calderas, respectively[5]. The Island Park Caldera supereruption (2.1 million years ago), which produced the Huckleberry Ridge Tuff, was the largest and produced 2,500 times as much ash as the 1980 Mount St. Helens eruption. The next biggest supereruption formed the Yellowstone Caldera (640,000 years ago) and produced the Lava Creek Tuff. The Henry's Fork Caldera (1.2 million years ago) produced the smaller Mesa Falls Tuff but is the only caldera from the SRP-Y hotspot that is plainly visible today.[6]

Non-explosive eruptions of lava and less-violent explosive eruptions have occurred in and near the Yellowstone caldera since the last supereruption. The most recent lava flow occurred about 70,000 years ago, while the largest violent eruption excavated the West Thumb of Lake Yellowstone around 150,000 years ago. Smaller steam explosions occur as well; an explosion 13,800 years ago left a 5 kilometer diameter crater at Mary Bay on the edge of Yellowstone Lake (located in the center of the caldera).[7][8] Currently, volcanic activity is exhibited via numerous geothermal vents scattered throughout the region, including the famous Old Faithful Geyser, plus recorded ground swelling indicating ongoing inflation of the underlying magma chamber.[9]




Quote:
No eruption that big has occurred while humans have walked the earth,

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Just because you don't take an interest in politics doesn't mean politics won't take an interest in you.... Pericles (430 B.C)