A major complaint of inhabitants living in the danger zones
around active and potentiallyactive volcanoes is that they
do not know what is going on, particularly when the volcano
is inactive. Keeping the local population fully informed before
an emergency improves its response during a crisis.
School programmes are a particularly effective way of raising
hazard awareness among children and their families. Ensure
that teaching about the volcanic threat remains a part of
school curricula throughout the year.
Conduct periodic exercises to acquaint the public with procedures
and to test and refine emergency measures.
Many organizations (for example the United States Geological
Survey and the Montserrat Volcano Observatory) have produced
educational materials about volcanoes and volcanic hazards
that are ready to use.
Preparedness means investing in ways to minimize the impact
of disaster. Preparing today will save lives tomorrow.
The scientists' main task during an emergency is
to monitor the volcano, to forecast its behaviour,
and to deliver information to the Emergency
Management Committee. The information will
then be used by the EMC to issue warnings to
the general public. Remember that eruption
forecasting is not a precise science, so that the
monitoring team will be under pressure not only
to issue timely information, but also to interpret
reliably the signals obtained from the volcano. It
is therefore important to create conditions that
allow scientists to focus on their tasks without
distraction from other groups, especially from
the media, who may use leaks and incomplete
information to create an 'exclusive' story. It is
equally important, however, not to isolate the
scientists from the public, as this can engender a
degree of frustration and a feeling that the 'true
facts' are being with-held as part of a perceived
hidden agenda. |
Even using the most sophisticated methods, scientists cannot
provide perfect forecasts. They can, however, estimate the relative
probabilities of whether or not an eruption is imminent and
of the type or style of eruption. This means that their forecasts
will always contain some uncertainty. The case is similar to
forecasting the weather. For instance, when tracking a hurricane
across the Atlantic, forecasts can change by the hour as to
when a hurricane will reach the Caribbean and whether or not
it will strike a particular island. Normally, the monitoring
scientists will present a forecast as a probability. For example:
there is a ten percent chance of lava
dome collapse and associated moderate explosive eruption during
the next seven days. The scientists should also provide
supporting information - on the basis of hazard and risk maps
that they have compiled - about the resulting eruptive phenomena
and the area likely to be affected (see below). Armed with this
information, it will then become the EMC's responsibility -
and not that of the scientists - to decide how to react to an
eruption forecast. It is therefore crucial that you understand
and appreciate the limits to forecasting techniques.
Before an eruption, scientists can advise on:
The probability of an eruption in the mediumto- long term (10-100
years). This is based on the frequency with which your volcano
is known to have erupted in the past. Remember that records
are usually incomplete, so that the probabilities can only be
used as general guidelines for planning development and the
design of escape routes during a crisis.
Whether or not a volcano is becoming active. This is based on
unusual signs of unrest, such as local, small earthquakes or
ground uplift. Such signs do not mean that a volcano will erupt,
only that new processes are occurring beneath the surface and
that these might lead to an eruption. When such unrest does
lead to an eruption, it is commonly detected several weeks or
months before the eruption occurs. Enough time is thus normally
available to increase the efficiency of the network of instruments
monitoring the |
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