Page 14 - 2018-Issue1

Volcanic Eruptions

and Aviation

BY KLAUS SIEVERS

VOLCANIC ERUPTIONS IN GENERAL instruments on the ground, or even by future behavior of a volcano, if possible.
Volcanic eruptions have been going on sensitive instruments on satellites. Despite their measurement capabilities, it is
since the formation of the Earth, and there is VOLCANIC CLOUDS AND AVIATION still beyond the present state of the art to
no end in sight. They are perfectly natural Useful information on the dangers posed provide accurate predictions months or weeks
phenomena and the gases, aerosols, and solid by volcanic clouds can be found in ICAO before an eruption.
components that are brought up to the surface documents such as ICAO Doc 9974, Flight If circumstances are right and the volcano
and atmosphere are 100% natural. Eruptions Safety and Volcanic Ash. This document has been monitored with the right instrumen-
cannot be influenced by humans. You cannot includes a description of dangers caused by tation, a short-term eruption prediction may
stop an eruption by placing a “cork” into the volcanic eruptions and provides information be possible. However, due to the limited
opening (caldera) of a volcano. on the safety risk assessment process with budgets of most volcano observatories, not all
The science of forecasting if and when an emphasis on volcanic ash aspects. Further volcanos are monitored that extensively. If a
eruption will occur or how strong it will be, is details on volcanic clouds and their impact on prediction can be made, it will not be precise
based upon indications and measurements. aircraft systems can be found in the ICAO Doc as to the hour or the nearest 1000 feet of
Tremors underground can be measured and 9691, Manual on Volcanic Ash, Radioactive eruption height. Precision predictions are
the build-up of pressure inside a volcano can Material and Toxic Chemical Clouds. This something we may expect only in the distant
sometimes be inferred from the expansion of document also contains information about ash future. In practice, there are still surprise
its flanks by a few centimeters. Other encounters and their effects on aircraft. Finally, eruptions of sparsely monitored volcanos, as
observable indications may be the rising of ICAO DOC 9766, Handbook on the with the 2011 eruption of Nabro in Eritrea,
parts of the earth near a volcano, changes in International Airways Volcano Watch (IAVW), near the Ethiopian Border.
the salinity of a stream, or a rise in the explains the entire system of volcano The World Organization of Volcano
temperature of lakes and hot springs. observatories and Volcanic Ash Advisory Observatories can be found here:
In Iceland, cauldrons form in old, deep Centers (VAAC) in detail. www.wovo.org/observatories/
glaciers because they experience heating from VOLCANO OBSERVATORIES Besides monitoring volcanos, another
below; presumably by magma that has moved Volcano observatories perform the important task of volcano observatories is to
closer to the surface. Surface heating can be measurements and observations at a volcano. report on eruptions. They may take different
observed in some volcanos through the use of They provide reports and opinions on the forms, like lava oozing to the surface, with little

ISSUE 1 | 2018 InterPilot | The Safety and Technical Journal of IFALPA