This dataset shows the tsunami evacuation zones for the
Chatham Islands Council, drawn in December 2017.
What do the zones mean? The Red Zone is the shore
exclusion zone, including beaches, estuaries, river mouths and Te Whanga
Lagoon. Even if a tsunami is not big enough to flood land, it can cause strong
and unusual currents in the water, and unpredictable surges onto beaches, which
can knock people off their feet. The Orange and Yellow Zones are land
evacuation zones. The Orange Zone could be flooded in a large tsunami, and the
Yellow Zone could be flooded in a rare, very large tsunami. You need to
move out of all zones if you feel an earthquake that is either long (shakes for
more than a minute) OR strong (shaking so strong it is hard to stand up),
without waiting for an official warning or for anyone else to tell you what to
do – a tsunami may arrive from nearby. In an official tsunami warning –
when we have more time before the tsunami will arrive – you will be told which
zones you need to move out of, depending on how big the tsunami is likely to be
when it arrives.
How are the zones drawn? The area flooded a tsunami depends
on many things – the size of the earthquake, the direction it is coming from
and the tide level when the waves arrive. We can never say for sure exactly
which areas will be flooded in a tsunami. When drawing tsunami
evacuation zones we consider many different tsunami scenarios. The evacuation
zone boundaries are drawn further inland than the worst tsunami flooding we
would expect in a 2500 year time frame – we’d rather err on the side of
caution. The zone boundaries often follow some sort of feature that
is easy to see on the ground, like roads, so that you know whether you are in
or out of the zone.
You can find more information on how and when to evacuate on
the Chatham Islands Council website at www.cic.govt.nz,
or visit the Chatham Islands Council office in Waitangi.
