RSVP: Joseph Evinger (jdevinger@comcast.net)
When:
Every 2nd Thursday of the month, 3:00-4:30 pm
Where: Zoom - https://us02web.zoom.us/j/84801461083?pwd=elp5eDJ3V0F4bUhUVzFwS2MzWm1oZz09
Meeting ID: 848 0146 1083
Passcode: science
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Meeting ID: 848 0146 1083
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Science and Ideas Group
Volcanic Super-Eruptions and Yellowstone
Professor Stephen Self
Earth and Planetary Science Dept
University of California, Berkeley
Talk summary:
Every now and again, Earth suffers from tremendous explosive volcanic eruptions, much bigger than those witnessed in modern times, which have a truly global impact. Although the return period for such events is long, perhaps every 20-100,000 years, it is more likely that Earth will next experience a super-eruption (defined here as one producing > ~ 400 km3 of magma) than a large meteorite impact.
Depending on where the volcano is located, the effects of such an event will be felt world-wide, or at least by a whole hemisphere, and the associated phenomena will spread quickly within a couple of weeks. These effects include temporary darkness with loss, or severe reduction, of solar radiation reaching the surface, unseasonable cooling and warming, coupled with strange weather patterns, and, of course, widespread ash fallout. Major disruptions of all services that our present society depends on can be expected for periods of months, to even a few years.
Past explosive super-eruptions, including the latest huge one, the Toba event in Sumatra 74,000 years ago, will be discussed. We will put the likely risk of another great eruption at Yellowstone into its proper scientific perspective. We must ask: Is our global society ready for the next explosive super-eruption?
Professor Stephen Self: Steve has studied volcanic rocks in many parts of the world, concentrating on large (flood) lava effusions, explosive eruptions, and the impact of volcanism on the atmosphere. His current research interests include mechanisms and products of flood basalt and explosive super-eruptions plus several other projects (see www.stephenself.com). He has published and lectured widely on the impact of large-scale volcanic eruptions on the environment and society, relevant to both our present and future world, and past Earth history. Steve lives in Alameda, California, and retired in 2018 from his position as Senior Geologist/Volcanologist with the US-Nuclear Regulatory Commission. Steve is a Fellow of the American Geophysical Union, the Geological Society of America, and the Geological Society (London). He is pictured in 2019 at Stonehenge in England.