Volcanoes - Ministry of Civil Defence and Emergency Management

experts and workshopped through the probabilities, we
cannot get away from the fact that we do have a major
problem in the hazard field with volcanoes.
Now that the CDEM Act 2002 is a reality, we
have formed our Bay of Plenty Civil Defence Emergency
Management (CDEM) Group. Along with the support of
the Coordinating Executive Group (CEG) our relevant
working groups are going through a very robust process
of deciding on the hazards affecting the Bay of Plenty
Region, with volcanic eruption high on the list.
RESEARCH INDICATORS
Major earthquake and volcanic features of the Bay of Plenty
occur. How prepared will the community be? How
prepared will those vested with the responsibility of Civil
Defence Emergency Management be? The problem will
not go away. The community must be resilient and accept
that there are precautions and measures we all must take.
The effects of a volcanic eruption and the effects
of a distal eruption have been well researched over
the past few years. Environment Bay of Plenty has
commissioned a number of studies with the Institute of
Geological and Nuclear Sciences (GNS) and universities.
These studies have proved to be invaluable in coming
to grips with the magnitude of the problem. A number
of graduates have prepared theses for Doctorates and
Masters Degrees on various aspects of the effects of the
“Big One”. This big one being a volcano rather than our
other major hazard of earthquakes. The fact that these
people are interested in delving into the reasons why,
and the possible effects of volcanic activity has certainly
been a huge asset for those deciding on an emergency
management approach. Having ploughed through the
valuable data available and sought the advice of the
The 1315AD eruption from Mt. Tarawera was
the largest volcanic episode to have occurred in New
Zealand in the last 1000 years. Environment Bay of
Plenty held a “Kaharoa Eruption Hazards Workshop”
in October 2000 where the event was studied and
implications drawn for a present day scenario. The
results, as found by Russ Martin and Ian Nairn for
“Volcanic Hazard Planning” in summary were:
• The need to manage lengthy pre-eruption phases
(1-10 years duration), with the likelihood of false
alarms, conflicting scientific views on the likely
outcome, sensational media treatment, public anxiety,
and possibly severe adverse local economic effects.
• The need to make detailed plans for an impending
event of unknown start time, size, duration and
(wind-controlled) ashfall scenarios.
• The need to manage a long-duration eruption with
multiple large explosive events so that some areas
receive repeated ashfalls over several months.
• How to recognise (and guarantee) that the
eruption has ended.
• Assessment of the necessity and feasibility of
engineering intervention to reduce post-eruption
flooding and sedimentation hazards.
• The post-eruption impact on local government in the
region and its functions.
• When to start on clean-up operations, how to fund
these, and how to select the priority areas.
• How to manage the situation of accommodating and
rehabilitating perhaps up to 200,000 evacuees from
the region?
We can see from the above that the hazard
implications are a grave cause for concern. For a
Project Manager such as myself with the task of editing
and putting together the Bay of Plenty Civil Defence
Emergency Management Group Plan, these studies are
invaluable. Our Plan will go a long way to make the
critical decision-making easier.
As we read through the implications, the
enormity of a volcanic eruption quickly becomes
apparent. We are not talking about days, weeks or
months but possibly years before anyone is allowed
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TEPHRA
June 2004