<b>Clouds in the Sky Keep Us Standing In-Line</b>

Last month, a significant eruption of the Grímsvötn volcano in Iceland reminded us just how valuable air space can be. Thousands of passengers were grounded and approximately 900 flights delayed, as volcanic ash jeopardized air travel.

The recent eruptions in Iceland are typical of hot spots and mid-ocean ridges. In Iceland, dense lava flows buried by glaciers have released a considerable amount of volcanic ash, greatly affecting European air travel. These dense magnesium and iron-rich lava flows are locally abundant, emanating along a spreading ridge. The hot spot has caused the formation of Iceland and the surrounding island chain in the mid- Atlantic. High temperature gradients, an abundance of geothermal forces and a rather thin section of Earth's crust characterize these eruptions. The diverging tectonic plates leave us with an abundant supply of lava, filling the gap with regular patterns of volcanic activity. As quickly as the headlines of Grímsvötn diminished, we now turn our eyes south to Chili.

The eruptions of the Puyehue-Cordon Caulle Volcanic Complex (PCCVC) in Chile are associated with the "Ring of Fire." The flow of lava in this location is fed by a subduction complex. Lava flows in this location are basaltic-rich. Although similar in composition, as there is only a negligible amount of crustal contamination in the rising magma, the dynamics behind the lava flow are significantly different. The rising magma and underlying calderas are fed by a subduction complex, or rather the melting of the subducted slabs which are remnants of the Pacific plate. By nature, these volcanic eruptions are more violent and are known to be associated with the largest recorded earthquake in modern history, the 1960 Valdivia earthquake.

The current eruption in Chile is typical of volcanic activity along a volcanic arc. Rising mamga is collected in calderas, melting away silicate-rich rocks in the continental crust. The associated volcanoes lie dormant for decades if not centuries before a new vent is found, allowing the building pressure from rising magmas to be released. The display in Chile is much more significant, however, as European and North American air travel remains unaffected; its occurrence seems to hold modesty to its true explosive nature.

Resources:

http://en.wikipedia.org/wiki/List_of_volcanoes_in_Chile

http://en.wikipedia.org/wiki/Puyehue-Cord%C3%B3n_Caulle

http://www.ainonline.com/news/single-news-page/article/air-travel-disruptions-from-chile-volcano-spread-across-south-pacific-30006/

http://earthquake-report.com/2011/06/12/series-of-moderate-earthquakes-in-chile-argintina-lake-district-may-set-off-the-eruption-of-puyehue-cordon-caulle-volcanoes/