APM Welcome, APM North West Network Conference, Synergies Across Sectors
Volcanic Hazards.pptx
1.
2. A volcano is a mountain
or hill, typically
conical, having a crater
or vent through which
lava, rock fragments,
hot vapor, and gas are
being or have been
erupted from the
earth’s crust.
3. A volcanic hazard
refers to any
potentially dangerous
volcanic process that
puts human lives,
livelihoods or
infrastructure at risk
of harm.
6. Tephra is a general
term for airborne
pyroclastic material
ejected during the
course of a volcanic
eruption.
7. Ash fall is a rain of
airborne ash resulting
from a volcanic
eruption. It can have
serious detrimental
effects on agricultural
crops and livestock
depending mainly on ash
thickness.
9. Pyroclastic surges are
low density flows of
pyroclastic material.
The reason they are
low density is because
they lack a high
concentration of
particles and contain a
lot of gases.
10. There are three types of pyroclastic
surges: 1) base surge, 2) ash cloud surge,
and 3) ground surge. A base surge is usually
formed when the volcano initially starts to
erupt from the base of the eruption column
as it collapses. An ash cloud surge forms
when the eruption column is neither buoying
material upward by convection or collapsing.
A ground surge usually forms at the base of
a pyroclastic flow.
11. Volcanic gases are
composed mainly of
water, carbon dioxide,
and sulfur dioxide.
During violent
eruptions, these gases
are injected into the
stratosphere.
12. Lava flows are streams
of molten rock that
pour or ooze from an
erupting vent. Lava is
erupted during either
nonexplosive activity or
explosive lava
fountains.
13. A debris avalanche is
a large-scale landslide
that travels at high
speed of up to
100m/s, and can flow
for distances of 10km
or more.
