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Obj. 1. Students will name and describe the hazards caused by
volcanoes.
III. Volcano Hazards
a. Gas – the three major gases produced by volcanoes are
water vapor (H2O), carbon dioxide (CO2), and sulfur
dioxide (SO2).
1. High concentrations of CO2 can cause death while
smaller amounts may cause brain damage.
2. High concentrations of SO2 can change global
temperatures by making it colder. The SO2 reflects
the suns rays which prevents heating of the Earth. SO2
when mixed with H2O creates sulfuric acid (H2 SO4)
which causes:
a. acid precipitation
b. burns the skin and respiratory tract
c. irritates the eyes and throat
b. Lahars – are incredibly deep rivers of natural concrete
(contains trees, water, rocks, dirt and lava) that buries
everything in the way.
c. Tephra (not lava) – are the objects that volcanoes spew
forth. They come in various shapes, with various names,
such as:
Dust – the smallest particles, Ash – slightly larger particles
than dust, Lapilli – pebble-like particles, Volcanic bombs –
are pieces of lava thrown from the volcano and hardened in
the shape of round boulders, and Volcanic blocks – pieces
of rock the size of cars or larger thrown from the volcano.
d. Pyroclastic flow (the worst kind of volcanic emissions) –
massive amounts of rocks, gases, ash and various other
tephra that follows the natural lines of the mountain. It
travels within the grooves and valleys of the mountain. It
contains major heat (1,000+ degrees), gases, and tephra all
which cause severe burning, choking and smashing.
e. Landslides – earthquakes caused by the volcano cause very
large sections (blocks) of mountain to fall away.
f. Mudslides – occur because of a major snow melt due to the
heat from the volcano. When the water and dirt mix, it
creates a mudslide.
g. Lava flows – molten rock from the volcano contains
(typically) high heat which burns and buries everything
within its path and then solidifies.