Sunday 13 March 2011

Look at the ways that volcanic eruptions can be predicted

Why predicting the eruption of volcanoes are important:
  • Volcanoes are able to destroy large areas of land during eruption
  • Volcanoes can kill and injure many people during eruption

Ways to watch on volcanoes:
  • Volcanoes can be continuously watched on by accurate measurements
  • But the methods used to monitor the volcanoes are expensive
  • They require skillful operators with complicated instruments in observatories
  • Not all countries can afford to watch on their volcanoes

Most important methods & instruments used to predict eruption:
-Seismographic monitoring
http://www.yourdemocracy.net.au/drupal/files/images/IRIS%20Seismic%20Monitor.jpg
  • Magma rising from a volcano causes moderate Earth tremors
  • As magma gets closer to the surface of the Earth, the tremors would occur more frequently and get stronger
  • These volcanic tremors are probably the most reliable sign to tell us that a volcano is going to erupt soon
  • These tremors can be detected by automatic telemeter recorders, where the results are immediately sent to an observatory for analysis
-Tiltmeters
http://www.ags.gov.ab.ca/graphics/turtle_mountain/Tiltmeters_figure_sm.jpg
  • Tiltmeters are made up of 3 graduated pots put together into a triangle
  • They are either filled up with water or mercury and are very accurate
  • Ground deformation is frequently caused by magma rising within a volcano
  • Tiltmeters measures ground deformation
  • When the rising magma causes a bulge, tilting is measured
  • As the volcano is about to erupt, this process takes place slowly
  • This process is expensive and is still in its developing stages
  • However, it may be the best way to predict volcanic eruptions in the future
  • The Global Positioning System (GPS), is used to measure displacement on the ground, including those near to volcanoes, which might predict eruptions
  • Orbiting satellites help the GPS to collect data
The above 3 methods are commonly used together

Signs of a volcanic eruption:
-Gas and steam may emit from a volcano before an eruption
  • An increased amount of gas emissions and steam from furmaroles, mudpots, and solfataras usually show that the magma is rising nearer to the surface of the Earth
  • Furmaroles are vents giving off gases or steam and are found on both active and dormant volcanoes
  • Solfatara is an Italian word used to describe a furmarole that gives off sulfurous gases
  • These information are not easy to collect as the gas emissions may damage the instruments and also harm the people collecting these information
After a volcano is studied:
-Hazard assessment maps may be created
  • These maps show the areas of most danger and highest risk around a volcano
  • It is important for the dangerous and risky areas to be correct and highlighted in detail
  • This is to allow the people living in those places to evacuate before the volcano erupts

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