Aviation hazards from volcanoes: the state of the science

The hazards wrought on society by volcanoes have been studied, discussed and reported extensively. Danger from volcanoes can occur on the land, on the sea and as this Special Issue highlights, in the air as well. The great eruptions of Vesuvius in AD 79 (Etienne 1992), Pelein 1902 (Fisher and Heiken 1982) and Krakatau in 1883 (Self and Rampino 1981) caused widespread devastation and killed thousands of people. During the eruption of Vesuvius, the town of Pompeii was destroyed by pyroclastic flows and the mummified remains of some of the inhabitants bear testament to the dangers and rapidity of volcanic hazards. It is reported that 36,000 people lost their lives in the aftermath of the climactic eruption of Krakatau; many of these unfortunate people were killed by the tsunamis that followed the collapse of several km 3 of rock into the sea. Shipping was particularly vulnerable during the eruptions of Krakatau and continued to suffer for more than 1 year following the major eruption. Atmospheric hazards from eruptions have also been studied, and a good example of the consequences of sustained eruptive activity on society is the 1763 Laki fissure eruption. Over a period of several months, the Laki eruption generated sufficient quantities of hazardous gases (SO2, HCl and HF) to kill more than 50% of the Icelandic livestock and severely affected the health and well-being of the population (Thordarson et al. 1996). Impacts on human health from several different volcanic erup- tions are described by Baxter (2005). Societal vulnerability and risk from volcanic erup- tions on land, on the sea and in the atmosphere are serious (Blong 1984)—considerable resources are expended to guard against and respond to these hazards. In the modern era, since the introduction of transcontinental air travel, a new threat from volcanoes has emerged: volcanic ash in the upper troposphere, where jet aircraft fly, can cause jet engine failure (loss of power), damage to turbine blades and pitot static tubes, with the possibility of the loss of the aircraft and lives (Casadevall et al. 1996). The increase in passenger air traffic (growing at an average of 5% per year, globally) (ESCAP 2005) coupled with the