Prediction of Volcanoes It is extremely difficult to predict volcanic eruptions as each has different patterns and shows different signs before erupting. Accurate prediction requires volcanologists to carefully monitor a volcano’s vital signs. Despite these difficulties, volcanic prediction has developed greatly over the past number of decades. The eruptions of Mount St Helens in 1980, Mount Pinatubo in 1992 and Mount Merapi in 2010 were all successfully predicted. These predictions helped to save the lives of tens of thousands of people living close to the volcanoes.
: Fig. 3.19 A volcanologist at work on a lava flow
Instruments Used and Eruption Indicators Volcanologists use a variety of instruments and tools to detect and record volcanic activity.
Earthquake activity always increases beneath a volcano prior to an eruption. Seismometers and seismographs are used to measure movements in the Earth’s crust, detecting and recording earthquakes. Seismometers are placed within a 20 km radius of a volcano’s vent. It is vitally important that seismometers are placed in the correct locations as many earthquakes that occur prior to eruption are very small and difficult to detect. If seismometers are placed too far away, these small earthquakes could go undetected.
Mass Pen Rotating drum
The earthquakes occur as magma and volcanic gas force their way upwards through cracks and vents in the crust. As the magma rises upwards, it causes rock to vibrate, triggering earthquakes. These earthquakes serve as warning signs that an eruption is going to
occur. This is how the eruption of Mount : Fig. 3.20 A seismograph Pinatubo was predicted. Ground Deformation GEO DICTIONARY
Deformation: change in the natural shape
Electronic distance measurement (EDM) devices, tiltmeters, GPS and satellite radar are used to check for any ground deformation. Ground deformation is one of the most obvious signs that a volcano is close to erupting. As pressure from rising magma and gases increases, volcanic mountain peaks swell shortly before eruption.
