It seems that in recent years some of the most severe hazards have taken place. Their enormous destructiveness goes hand in hand with the suffering of the people concerned. Many of us will ask ourselves why such disasters could not be prevented in times of modern technology and high scientific know how. But like weather, volcanoes or earthquakes cannot be influenced by the human intelligence. Life would not be life if we could control everything, even if it is difficult to comprehend why these terrible things do happen.
I have written this article to explain a little about the nature of volcanoes and earthquakes.
Especially volcanic eruptions and earthquakes are devastating natural hazards which are both difficult to predict and difficult to respond to.
However, examples like Montserrat, Mount St. Helens, Heimaey, the San Francisco earthquake and the Mexican earthquake illustrate the differences in terms of predicting and responding to these hazards.
Volcanic eruptions are easier to predict than earthquakes, as minor earthquakes are often the first 'sign' of a following volcanic eruption. The example of Mount St. Helens underlines this, as first signals of a coming volcanic eruption could be noticed already three months before the actual eruption. These signals can be either minor earthquakes or even gas production in a volcano shows that it is 'active.'
Earthquakes are harder to predict as they occur suddenly without any warning or with short notice. However both earthquakes and volcanoes can be monitored and observed by seismographs, tilt meters, lasers, GPS and observation. Furthermore some animals like catfishes can be used to predict them as they are very sensitive. It is also possible to create hazard maps as prediction for volcanic eruptions. These are based on previous eruptions and close observations.
The example of Heimaey in Iceland shows that volcanoes can also occur unexpectedly. It erupted without any previous signs on January 23rd 1973. In this case there were only 24 hours of minor tremors before a 400 metre fissure opened up to pour out lava. The Heimaey is only one example where a volcanic eruption occurred without previous warning. Other examples like Mount St. Helens and Montserrat show that volcanic eruptions are usually easy to predict. Mount St. Helens for example resulted in the largest landslide in recorded history with a speed of 70 to 150 miles per hour. But due to great preparedness only 57 people died. This shows that early warning results in easier and more accurate prediction.
As a general rule, it can be said that earthquakes are more difficult to predict than volcanoes as they occur without any warning.