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Dealing with Volcanic Threats
Photo: Courtesy
of NGDC/NOAA What do you do when the volcano in your own back yard
erupts? Call your family volcanologist? ("Sandbag the river bank and call me in the
morning....") What if it is your responsibility to make an evaluation or to take
action? First, you must gather information to determine the current situation (seismic
activity, active eruption, etc.) and evaluate the potential type and magnitude of hazards
associated with the current situation. Then you must choose a response to the threat.
Options include, but are not restricted to the following:1. Ignore. The situation may warrant no further concern.
2. Wait and watch (Literally). The situation
may only need careful continuous monitoring without restricting the movement of the
people.
3. Put monitoring system in place. The
technology exists to put sensors in place that will detect a variety of changes in a
volcano, like inflation or seismic activity. A system of motion sensors high in a valley
prone to mudslides can give some early warning to communities farther down the valley.
(The warning time depends on the sensor's distance upstream and the speed--typically 40 to
50 mph--of the mudflow.) Many volcanoes already have some monitoring systems, but most do
not.
4. Restrict access to an area. Rather than
total evacuate, you may choose to allow certain types of people into the danger area, such
as businessmen or employees of companies operating in the area, owners of private homes in
the area, police or forest rangers, or geologists monitoring the volcano. You must decide
whom to restrict and why.
5. Evacuation of an area around the volcano.
The size and location of the evacuation area depends on the projected size and type of
eruption. You may only need to evacuate particular valleys (as in the case of local lava
flows or mudflows), or you may need to evacuate all around the volcano for many miles.
Some eruptions may throw ash high enough to affect passing aircraft, in which case you may
want to restrict movement in a large airspace around the volcano.
6. Brace for the "End of the World."
An eruption may be so large that there are no practical responses.
7. Something else? The possibilities are
limited only by your creativity.
Remember that any action taken will have consequences. Some, like #2 and
#3, cost money for equipment and/or people--money that will have to come out of somebody's
pocket. Any kind of access restriction or evacuation will cost money, disrupt lives, and
take time. Businesses, like hotels or grocery stores in a restricted area, will lose money
due to loss of customers; others, like lumber companies and mines, will lose access to
their means of production. You will have to balance the potential risk to public safety
against the needs and interests of private individuals. In our society, individuals can
often exert excessive pressure on decision makers to choose courses of action that may not
be in the public interest (remember St. Pierre). As an evaluator or decision maker,
you need to be as honest and accurate in your judgments as possible; because if you are
wrong, you may cause needless disruption, economic hardship, or the loss of life.
[ Volcanoes & Climate ] [ Monitoring Volcanoes ]
[ Volcanic Hazards ] [ Dealing with Volcanic Threats ]
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