Mod 6.3 - Prediction and Prevention (Volcanoes)

Question 1

What is the advantage of predicting volcanic eruptions

Answer 1

Predicting a volcanic eruption has one simple advantage over predicting earthquakes and weather events - the volcano has a known location. As such, monitors can be placed on the ground around the volcano and satellites can be programmed to collect data on that location, making it much easier to effectively monitor volcanic activity and predict volcanic eruptions.

Question 2

3D Imaging

Answer 2

Changes in the shape of a volcano can indicate rising magma and an imminent eruption. For example, as fresh magma enters the magma chamber beneath the volcano, it may bulge outwards, as did the north flank of Mt St Helens before the large landslide and eruption in May 1980. Instruments such as tiltmeters, strainmeters, GPS and radar are used to detect 3-dimensional variations caused by the movement of subsurface magma. 3D imaging allows scientists to organise data into digital models and 3D image reconstructions to monitor and view changes in the magma chambers and mountain swelling, therefore allowing for effective monitoring and prediction of volcanic eruptions.

Question 3

Seismic data

Answer 3

When the earth’s crust moves, it emits shockwaves which are detected and recorded by a seismometer. Signals are sent to a nearby observatory where computer models analyse the data in real time. Seismic data, in conjunction with deformation measurements can be used to track the movement of magma beneath the surface and predict eruptions. Thus, establishing a network of seismometers and tiltmeters to monitor magma activity would give early warning of a potential eruption that could produce hazardous lava flows. This allows early evacuation of people from high-risk areas, thus minimising harm to people.

Question 4

Early warning signals

Question 5

Ground movement data

Answer 5

Changes in the shape of a volcano can indicate rising magma and an imminent eruption. Ground movement data allows the position, shape and slope of a mountain to be monitored, and scientists can observe changes to make predictions. For example, seismographs that monitor movements in the Earth’s crust send signals to a nearby observatory where computer models analyse the data in real time. Tiltmeters are sensitive instruments that measure minute changes in slope, which can provide information about magma activity. Thus, establishing a network of seismometers and tiltmeters to monitor ground activity would give early warning of a potential eruption that could produce hazardous lava flows. This allows early evacuation of people from high-risk areas, thus minimising harm to people.

Question 6

Historical data

Answer 6

Historical data which shows repeating patterns of behaviour can provide an eruption history of a volcano and likely behaviours and frequencies of future eruptions. This improves the reliability of predictions allowing scientists to provide sufficient warning to local communities to evacuate the region before the eruption occurs. While this may not reduce the damage caused by the eruption, it is possible to save many lives.

Historical documents from the past few hundred years, as well as older traditional stories of particular mountains often coincide with historical geological data to depict a reliable record of a volcano’s behaviour patterns. However, historical documents alone are of limited reliability, as they could be exaggerated or minimised, misinterpreted or changed over time.