|
Dr. Markus Treml: Volcanic ash can be a very serious issue for air traffic. Because of that several so-called “Volcanic Ash Advisory Centres” (VAAC) were set up to continuously and globally monitor the situation and to issue binding advisories if necessary.
The modeling technique they use is state-of-the-art and the advisories are for ensuring 100 percent air traffic safety. With this philosophy in mind, such advisories are likely to be conservative and regional in scale.
This is accepted, however, because an exact definition of safe airspace corridors is not feasible, as this would require measurements at all altitude levels in all airspace.
Furthermore, the threshold concentration at which ash poses harm to aircraft is currently unknown.
The business interruption (BI) due to volcanic ash is currently not covered by insurance policies.
Only BI resulting from physical damage is covered, meaning that insurance cover would normally only apply when an aircraft is damaged by volcanic ash in the air—assuming that there was no aircraft-grounding order issued by the VAAC—causing some subsequent repair time.
Therefore, there were no significant losses for the insurance industry resulting from the Eyjafjallajökull activity.
For the immediate surrounding areas volcanoes can be extremely dangerous.
Their effects can take many shapes. The most devastating form of volcanic eruption is a pyroclastic flow. It contains hot and extremely fast-moving material that wipes out anything in its path. At the other end of the spectrum is a slow lava stream which is easy to escape from but can destroy property.
Apart from these direct local consequences, volcanic ash and gases can spread over large distances and be health hazards. Moreover, they can hinder or even stop air traffic and influence the global climate for months or even years.
Sixteen volcanoes are currently considered dangerous. They are distributed all over the world, in Indonesia, Russia, México, Columbia, the U.S., Japan, Congo, Guatemala, Papua New Guinea, and four in Europe: Vesuvius and Etna in Italy, Teide on the Canary Islands, and Santorini in Greece. However, these volcanoes are only selected because of their direct local effects.
Air traffic or climatic effects can be caused by any volcano. The Indonesian Mount Tambora eruption in 1815 caused 1816 to be a “year without a summer”. More recently, the Pinatubo eruption in 1991 on the Philippines caused global cooling of 0.3 degrees Celsius.
It is difficult to answer this question statistically and come up with a probability since the observation period is quite small. However, some examples give a flavor of the likeliness of those events.
In the last 50 years there were three eruptions that had a global effect on climate: the Agung eruption in Indonesia in 1963, the El Chichon eruption in Mexico in 1982, and the 1991 Pinatubo eruption.
It’s not by chance that tropical volcanoes are more likely to have a global impact on climate, as only their ashes and gases can easily be spread by global air circulation patterns. Eruptions in other latitudes are rather limited in climate impact.
In the past 40 years more than 100 encounters of aircraft with volcanic ash were reported, the most critical ones being the British Airways flight in 1982 over Indonesia and the KLM Flight in 1989 over Alaska. In both cases all four engines failed. Luckily, both aircraft could make a safe landing.
From an insurance point of view physical damage caused by volcanoes are property damages like any other. In many countries volcanic risk is part of the extended cover, together with earthquake and other natural perils. It surely makes sense for people living within the direct reach of a volcano. Moreover, volcanic ash can cause physical damage losses far away from the actual eruption site.
An eruption is a very rare event. Moreover, each eruption is different and may even change the volcano’s shape and therefore change the resulting lava flow pattern.
Furthermore, the consequences of an eruption also depend on current weather conditions and other circumstances. For these reasons it is hardly possible to develop a probabilistic risk model as we do for earthquakes or windstorms. Therefore, we use deterministic scenarios to get an idea of the affected area and possible losses.
Against direct effects such as ejection of large particles or lava flow one can actually do nothing or very little. There are attempts to channel lava flows with artificial barriers for some volcanoes where the eruptive pattern is smooth and well known. There are some things one can do against volcanic ash, such as storing dusk masks or taping doors and windows and protecting sensitive electronic equipment.
All major volcanoes are monitored by observatories and scientific survey networks that measure volcanic activity such as earthquakes and gas emissions. If the combination of these data indicates a possible eruption warnings are issued.
However, exact predictions are very difficult. Each volcano is very individual in its behavior and the level of understanding is very different for individual volcanoes.
As with all content published on this site, these statements are subject to our Forward Looking Statement disclaimer, provided on the right.
| 
