I've always been fascinated by natural hazards and therefore I decided to write this article on the subject.
There are many different factors which influence the magnitude and the frequency of either an earthquake or a volcanic eruption. But apart from this there are some major differences between earthquakes and volcanoes. Earthquakes for example are found on conservative plate boundaries, e.g. the San Andreas Fault in California. Whereas volcanoes are located on destructive or constructive plate boundaries, for example Mt. St. Helens or Heimaey in Iceland. But they can also be created on a hot spot, places that have fierce heat in the mantle; Hawaii is located on such a hot spot.
Furthermore you need to focus on primary and secondary effects which are different in volcanoes and earthquakes. Primary effects of volcanoes are for example lava flows, ash clouds, ash bombs and pyroclastic flows, whereas earthquakes only have one primary effect which is the tremor.
But the secondary effects are much more vigorous with an earthquake, like tsunamis where flooding causes disease, or it could result in massive landslides as a consequence of the eruption. The most common secondary effect of earthquakes is fire which can cause both high economic and high social loss. The secondary effects of volcanic eruptions are mudflows or sometimes landslides.
How much a country or population is affected depends mainly on three factors: the magnitude and frequency of the hazard, the population density which determines exposure and the ability to minimise the damage. Levels of development, education, technology and resources all influence the vulnerability of the location. But also the risk has to be reviewed towards social, economic and environmental impact and the effects on global warming. Long term and short term consequences have to be considered.
For the people concerned it does not make much of a difference which hazard destroys their lives. They constantly have to live with this threat. Most of them don't have enough money to move away to protect themselves and their families. In most cases there is no way to solve this dilemma and people have to accept this 'catch-22.'
In the end we can say that both volcanoes and earthquakes do present a major risk to life. It depends to a great extent on the development of the country, as the social costs are evidentially higher in LEDCs as in MEDCs. This is mainly because of community preparedness, predictions and monitoring. But however as 70% of the world's population live in earthquake zones, they obviously present a greater risk to humans than volcanoes.
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