2. What is a
Volcano?
A volcano is a rupture in the crust of a planetary-mass object,
such as Earth, that allows hot lava, volcanic ash, and gases
to escape from a magma chamber below the surface. On
Earth, volcanoes are most often found where tectonic plates
are diverging or converging, and most are found underwater.
What is a Volcanic Hazard?
A volcanic hazard is the probability
a volcanic eruption or related
geophysical event will occur in a
given geographic area and within a
specified window of time
4. Lava Flows
Major hazards of lava flows --
burying, crushing, covering,
burning everything in their
path. Sometimes lava melts
ice and snow to cause floods
and lahars. Lava flows can
dam rivers to form lakes that
might overflow and break their
dams causing floods.
6. Ashfall can cause minor to
major damage to vehicles
and buildings, contaminate
water supplies, disrupt
sewage and electrical
systems, and damage or kill
vegetation. After ashfall,
affected airports must be
closed until ash is removed
because of its hazard to jet
engines.
Ashfall
8. Pyroclastic Flows & Surges
Pyroclastic flows are so
fast and so hot that they
can knock down, shatter,
bury, or burn anything in
their path. Even small
flows can destroy
buildings, flatten forests,
and scorch farmland.
10. Lahars
Lahar is an Indonesian word describing a mudflow or
debris flow that originates on the slopes of a volcano.
Small debris flows are common in the Cascades, where
they form during periods of heavy rainfall, rapid snow
melt, and by shallow landsliding.
12. Volcanic Gases
The effects of volcanic gases on life may be direct,
such as asphyxiation, respiratory diseases and skin
burns; or indirect, e.g. regional famine caused by the
cooling that results from the presence of sulfate
aerosols injected into the stratosphere during
explosive eruptions.
14. Volcanic Landslides
Landslides are common on
volcanic cones because they are
tall, steep, and weakened by the
rise and eruption of molten rock.
Magma releases volcanic gases
that partially dissolve in
groundwater, resulting in a hot
acidic hydrothermal system that
weakens rock by altering minerals
to clay.
16. Balistic Projectiles
Ballistic Hazard and Risk Management.
Ballistic projectiles are a risk to life on
active volcanoes and can cause
substantial damage to exposed
infrastructure and the environment due to
their high kinetic energy, mass, and often
high temperatures (Blong 1984).
18. Tsunami
Tsunamis can cause
great loss of life and
property damage in
coastal areas. Very large
tsunamis can cause
damage to coastal regions
thousands of miles away
from the earthquake that
caused them. Beaches,
lagoons, bays, estuaries,
tidal flats and river mouths
are the most dangerous
places to be.
