Presentation on theme: "Tom Pering “Super Volcanoes”. Today’s topics… What is a super eruption? Where do super eruptions occur? What do super volcanoes look like? “Super Volcanoes”"— Presentation transcript:
Tom Pering “Super Volcanoes”
Today’s topics… What is a super eruption? Where do super eruptions occur? What do super volcanoes look like? “Super Volcanoes” around the world. Yellowstone Caldera Chain Yellowstone Now What would an eruption at Yellowstone be like to live through? What are the chances of an eruption occurring in our lifetime?
What is a super eruption? You may know about super eruptions under the term “supervolcano”. Definition of a super eruption VEI 8 – Ultra-Plinian, Mega-Colossal
Lord Byron - Darkness “I had a dream, which was not all a dream. The bright sun was extinguished, and the stars Did wander darkling in the eternal space, Rayless, and pathless, and the icy earth Swung blind and blackening in the moonless air; Morn came and went -and came, and brought no day”
Plate Boundaries Hot Spots Mantle Plume Huge Magma Chambers Where do super eruptions occur?
What do super volcanoes look like? Caldera Volcanoes
Well known “super volcanoes” Yellowstone, USA Lake Toba, INDONESIA Taupo, NEW ZEALAND Not so well known “super volcanoes” La Garita Caldera, USA Cerro Galán, ARGENTINA Glen Coe, SCOTLAND Scafells, Lake District, ENGLAND
Glen Coe, Scotland Last eruption 420 million years ago Silurian (Paleozoic Era) 5 eruptions Roughly 500,000 years apart. Glaciations
Scafells, Lake District, England 440 – 520 million years ago (unknown last eruption) Ordovician (Paleozoic Era) Largest known phreatomagmatic eruption VEI 7 or 8? Glaciations
Lake Toba, Indonesia 74,000 years ago Largest Volcanic Lake in world Mankind survived
Taupo, New Zealand First Eruption – 300,000 years ago Oruanui Eruption 26,500 years ago Lots of volcanic activity nearby
La Garita Caldera, USA Colorado 26 million years ago Largest known eruption 5000 km ³
Cerro Galán, Argentina Andes Mountain Range 2.2 million years ago 1050 km ³
Yellowstone Caldera Chain
Yellowstone Eruptions Huckleberry Ridge Caldera, 2.1 million years ago 2450 km ³ Mesa Falls, 1.3 million years ago 280 km ³ Lava Creek, 640,000 years ago 1000 km ³ Source: USGS
Yellowstone Now National Park - over 3 million visitors a year. 307 million people in the USA An eruption at Yellowstone could be a small outflow of lava or an VEI 8 eruption. Large Magma Chamber
Warning signs of an imminent eruption High ground temperatures Increased volcanic gas emission Hydrothermal feature – activity increase Ground uplift Hydrothermal explosions Earthquakes Harmonic tremors
Possible regional effects of an eruption at Yellowstone Zone 1 – Pyroclastic Zone (Around 90,000 could be killed – 90% mortality rate) 100 km radius Zone 2 and 3 – Asphyxiation and Roof Collapse 3 million people trapped by ash Zone 4 Ashfall – 15cm Zone 5 Ashfall – 5cm Zone 6 Ashfall – 1cm
Different ways to die… Direct Asphyxiation Gas Poisoning Pyroclastic Flows Roof Collapse Burning Lahars Plane Crash Indirect Starvation / Drought Freeze Riots / Conflict
What could be the global effects of an eruption at Yellowstone? Water Contamination Food Shortages Increase Rainfall Economic Failure Extinction Volcanic Winter Triggering of an Ice Age
What are the chances of a super eruption occurring in our lifetimes? Are we overdue?
Further Reading http://www.yellowstonenationalpark.com/calderas.htm Yellowstone Volcano Observatory USGS
References Brenchley, P.J., Rawson, P.F., 1990? The Geology of England and Wales. The Geological Society. Bath. 256pp CIA World Fact book [Online] Cole, J.W., Milner, D.M., Spinks, K.D., 2005. Calderas and caldera structures: a review. Earth Science Reviews. 69, pp. 1-26 Grotzinger, J., Jordan, T.H., Press, F., Siever, R., 2006. Understanding Earth. W.H.Freeman. Basingstoke. Moore, I., Kokelaar, P., 1998. Tectonically controlled piecemeal caldera collapse: A case study of Glencoe volcano, Scotland. Geological Society of America Bulletin. 110 (11), pp. 1448-1466 Riciptu, L.R., Johnson, C.M., Sawyer, D.A., Lipman, P.W., 1995. Crustal and magmatic evolution in a large multicyclic caldera complex. Journal of Volcanology and Geothermal Research. 67, pp. 1 – 28 Wilson, C.J.N., 2001. The 26.5ka oruanui eruption, New Zealand: an introduction and overview. Journal of Volcanology and Geothermal Research. 112, pp. 133 - 174