VUL101

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VUL101 March 24, 2006 ENV235Y
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what is lava?
molten rock
different compositions
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how?
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where?
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where?
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magma vs. lava
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types of volcanoes subaerial submarine
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subaerial volcanoes
stratovolcanoes (Mt. St. Helens, Mt. Fuji)
shield volcanoes (Hawaii)
9 by 150 km (Hawaii) 3 by 15 km (Vesuvius) .3
by 1.5 km
cinder cones
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main dangers

• nuee ardente (pyroclastic flow)
• volcanic bombs
• gas
• Lahars (mud slides)
• landslides
• tsunamis
• earthquakes

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nuee ardente Mt. Pelee, May 8, 1902 St. Pierre,
Martinique
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fumes, ash, heat, blast 2 survivors
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lahars water, rock, sand, mud Nevado del Ruiz,
Colombia 1985
50 km/hr Surges Cement-like
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gas H2O, SO2, H2S, CO2 Lake Nyos, Cameroon, 1986
maar caldera-type depression from steam blast
above magma chamber
200 m deep (high P at bottom) dissolved CO2
became insoluble due to some instability
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climate Iceland, 1783
ash, SO2, CO2, aerosols, over Europe Ben
Franklin, 1989 eruption gt cold spell? Cold
spell gt
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Not all bad!!!

• creation of continents
• source of life at MORs (hydrothermal vents)
• creation of atmosphere oceans
• active role in plate tectonics

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volcano monitoring

• Active (past few centuries)
• Dormant (hundreds to thousands of years)
• Extinct
• gas (Mt. Pinatubo)
• heat flow
• ground deformation (Mt. St. Helens, Etna)
• remote sensing
• seismic

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ground deformation
electronic distance measurement
tiltmeters
satellite radar interferometry
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gas
SO2/CO2 fly-bys
direct sampling (long-term monitoring)
continuous monitoring
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Seismicity
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Mt. Pinatubo, 1991 2nd largest in 20th c.
800 dead 100,000 homeless SO2 decreases world
temperatures for years USGS saved 1000s