A hazard is a situation that poses a level of threat to life, health, property, or environment. There is a very big difference that helps prepare for a volcanic hazard and that is whether you are in a MEDC or a LEDC. In a MEDC monitoring volcanic zones and potential hazards is an option many LEDC’s don’t have. In Italy at Mt Etna they have Geochemical monitoring programs currently run by INGV which focus on the analysis of temporal changes, chemical changes and seismic activity. This option open to the Italians is not an option for LEDC who don’t have the wealth or public education to set up these stations. In Montserrat their where no levels of monitoring at all due to Before 1995 there was no record of the volcano on Montserrat erupting so they thought their was no need so it was an unnecessary cost. In 1995 the eruptions of the Soufriere hills began it eruption which berried a town and eventually killed 20 people in an unexpected pyroclastic flow.
Before the eruptions there was no preparations no warning. There were many effects of the eruption, one of them being 2/3 of the island was covered in ash, causing devastation and many homes being destroyed. As a result of this 50% of the island has to be evacuated to the north side of the island. Also Plymouth the capital of the island was covered in ash and became a ghost town Farmland was destroyed as well as schools and hospitals, the airport was also closed. This is the devastation caused with no preparation. But not only where their these primary factors but the Acid rain killed much of the islands Vegetation. MEDC can greatly reduce the hazards of a volcano in lots of ways. One key factor is warning which they can afford this means ample time to set up barriers and evacuate areas. Here are some examples of what you can do: ⎯creating an exclusion zone around the volcano
⎯being ready and able to evacuate residents
⎯having an emergency supply of basic provisions, such as food funds need to be available to deal with the emergency ⎯and a good communication system needs to be in place
These are precautions and not all countries can afford all of it.
There are other factors predicting and preparing wont help for. One is the type of volcanic hazard such as a sudden pyroclastic flow is much more violent then a slow lava flow. With pyroclastics you can only reduce the hazard by vacation but lava flows can be diverted and slowed down with dam wall trenches and spraying water As they did in ice land on the 1973 Heimaey eruption which started on 23 January.
Some times warning isn’t enough because of peoples different circumstances and beliefs they might not leave. One example is in Columbia in 1985 where they where warned but didn’t listen as they didn’t think they would be affected and didn’t trust the people telling them. About 20,000 people are feared dead after a volcanic eruption in northern Colombia. Four towns in the Andes region are reported to have been buried when ash spewed out of the volcano, Nevado del Ruiz, causing a mudslide. These people weren’t told to evacuate until 2 hours before the major eruption casing massive loss of life. The reason for this late call was because the country didn’t trust the people observing the volcano this meant the potential hazard was far greater then it should have been ad the results where horrific. This is one example of how poor education and different situation can greatly increase the hazard. The Nevado del Ruiz Volcano eruption is also a great example of how the physical environment affects the hazard. In Armero two rivers coming down from the volcano surrounded the worst affected town the town. This meant when the lahar formed it flowed down these rivers faster and stronger then it would have done land.
These rivers surrounding the town meant the lahar quickly surrounded and engulfed the town as they fueled the lahar as well. But other physical factors can have very different effects. At Mt Etna it has been active for about 500,000 years. This means that they have a large variety of data on past lava flow so they can predict patterns and theories of where the lava will most likely flow. This has meant that their settlement are built in the less active areas and that they can build canals before hand so they can easily redirect it. You can mitigate the Hazards to different extents in different circumstances. Some people and areas have far more opportunities then others though depending on location, hazard type, people and the country. But managed properly you can reduce the effect of many different hazards effectively though under the right condition but that is not always possible.
