BUSINESS

Measuring the Business Impact

Measuring the Business Impact

Volcanic Eruptions and Hazard to Aviation

Each year many volcanoes in the world are experiencing a rash. The largest of them, when they occur in populated areas, endangering the lives of people and causing extensive damage to infrastructure and crops. However compared to other natural disasters such as earthquakes, floods or severe droughts, the overall destructive potential of volcanoes is generally lower. Moreover, most eruptions, by their very nature, do not present a particular danger to living beings in the vicinity of volcanoes (Snedaker, 2007).

The various volcanic hazards 1) Lava flows - This type of phenomenon, although spectacular, is a less dangerous to human life than the buildings, infrastructure, communication lines, etc. ... Because the path of effusion probable may be more or less predicted, measures of diversion of flows can be considered. However such measures are not necessarily guarantees of success. The most viscous lava often advances slowly and over short distances and tends to pile on top of the mouth to form an eruptive lava dome. Such domes can collapse repeatedly and generate dangerous avalanches of hot blocks, ash-flows, and blasts.

2) Gases - The release of gas may take place during an eruption but also in non-eruptive period. Some of the gases emitted by volcanoes can be fatal at high concentrations. The reaction time available for an early warning is very short and intensive studies of this phenomenon with instruments in addition to ongoing monitoring of risk areas are strictly necessary to try to limit the risks. 3) The ash falls - The ashes that fall during an eruption do not directly and immediately endanger human lives, although the collapse of roofs under the weight of these volcanic products can occur. However, considerable damage can be caused to local agriculture and industries, even at distances of several tens of kilometers from the volcano.

4) Pyroclastic flows - This type of flows and surges of low density which are often associated with major volcanic represent a danger to people living nearby. Because these pyroclastic flows, which can sometimes reach temperatures near 800 ° C, pour out at speeds of several hundred km / h, the effective early warning systems for this type of phenomenon, are almost impossible. Even more dangerous situations can develop if these pyroclastic flows occur on volcanoes covered with snow or covered with glaciers, causing the sudden melting of these materials. 5) The lahars (debris flows and volcanic mud) - This type of phenomenon is also a major danger to residents, farmland and urban areas. Lahars can flow quickly and their destructive power is considerable. They can occur as a direct result of a volcanic eruption, for example in the presence of a crater lake, or as a secondary event caused by heavy rain during or after the eruption. The inhabitants of the more remote areas may still be warned several hours ahead. The presence of monitors and warning about volcanoes at risk is not a total guarantee of safety with regard ...