Plate Tectonics and Associated Hazards Hazard management of Volcanoes:

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Plate Tectonics and Associated Hazards
Hazard management of Volcanoes:
Prediction:
Easy to locate but difficult to predict exactly when activity will take place
The study of previous eruption history is important to understanding the type of activity
produced.
Research is being conducted to see if it's possible to predict the time of eruption using shock
waves that are produced as magma approached the surface when it expands cracks and
breaks rocks. ­ There was some success in predicting Popacatapetl in Mexico, 2000 but it
remains to be seen if techniques can be applied to all volcanoes
Example: late 1984 Nevado del Ruiz, a Colombian volcano came to life with smallscale
activity but Volcanologists were unable to predict where a major event would take place so
the majority of the population did not evacuate their homes. On 13th November 1985, a
violent eruption occurred with almost all the people still in their area. Melted snow and ice
resulted in Lahars sweeping down the valley and killing 20,000.
.
Protection:
Preparation for an event.
Monitoring the volcano to suggest a time when an area should be evacuated ­ looking at
land swelling, earthquake activity, changes in ground water level and chemical composition,
emission of gases, magnetic field and magma shock wave analysis.
Governments making risk assessments and producing a series of alert levels to warn the
public
Geological studies of deposits from former eruptions and associated ash falls ­ making it
possible to identify areas at risk and avoid building in such places
Divert lava flow
Foreign aid ­ monitoring, evacuation , emergency shelter, food, long0term resettlement and
restoration of the economic base and area's infrastructure.
Examples:
New Zealand government has produced a 5stage table to warn of the level of hazard to an
area.
Digging Trenches ­ Mt Etna, Sicily
Expolosive activity ­ Mt Etna, Sicily, 1983
Artificial barriers that also protect from lahars ­ Hawaiian islands
Pouring water on the lava front ­ Haeimaey, Iceland, 1973

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