* Volcanic
Eruptions
Convection
currents in the
mantle below.
subduction.
Magma
The Vent
Volcanic
eruptions are the
result of several
processes.
Movement of the
earth’s plates is
called…
When 2 plates
are pushed
towards each
other the heavier
or the …
In New Zealand
this process
happens off the
East coast of the
North Island in
the …
This collects in
vast chambers
where pressure
builds up because
of gases like..
As it moves
through this
towards the
surface it causes
small…
Plate Tectonics
Oceanic plate
Hikurangi Trench
The plates on
the crust move
about because
of large….
Is forced below
the lighter
continental
plate. This is
called…
As the plates
subduct friction
results. This
melts
surrounding
rock to form…
Sulphur Dioxide
and Hydrogen
Sulphide.
These cause the
magma to rise
through weak
spots towards
the surface in a
pipe called..
Earthquakes
These are
measured using
a…
Seisomograph.
Evacuate
Ash Cloud.
Water
Tangiwai.
Breathing
especially if you
have asthma
Another warning
a volcano is likely
to erupt is when
the temperature
suddenly
increases in the ..
The main
authority who
organises this is
the …
Rises into the air
often several km
high. Then solid
material called …
The other major
hazard is when
the heat of the
magma melts
snow on top of a
cone creating a..
When a rail
bridge was swept
away moments
before a train
from Wellington
came. It caused ..
The ash can also
get into engines
so roads are
closed and
airplane routes
are
Crater Lake.
Civil Defence
Tephra
Lahar.
153 people to
die.
Diverted
This will prompt
the authorities
to warn people
to be ready to ..
The first thing
that happens
when the
eruption begins
is that a large ..
May be ejected.
There may be
violent
explosions
especially if the
magma hits..
These move
very fast and
can sweep away
everything in
their path. This
happened at..
Other major
hazards result
from volcanic
eruptions.
People may
have difficulty..
The ash also
contains many
chemicals which
makes it..
Acidic
roofs
The All clear is
Given
Rehabilitation
This means that it
corrodes vehicles The water supply
and can make it a
health hazard if it
gets into ..
People are told
to disconnect
water supplies
and to sweep
their..
As the weight of
ash can collapse
them. It is
important to tell
people caught up
in an eruption
that they must
The most
immediate need
is to look after
the dead and
injured and
ensure ..
And Shut all the
windows. They
must stay here
until..
This is the first
Food and Shelter
stage of the
is given to those
recovery
affected
process. Long
term recovery is
called…
This involves the
repair of buildings
and roads. It also
ensures future
effects are
minimised by ..
This means
building walls to
direct lahar
flows and
zoning areas
most at risk.
Stay Indoors
Mitigation