But technological advances and improvements in recovery methods, as well as reduction of water usage and greenhouse gas emissions, have made oil sands a viable and popular option for the future of U.S. energy.

FORBES: America's Energy Future May Lie In Canada's Oil Sands

Volcanologist Sonia Calvari, of the Institute of Geophysics and Volcanology in Catania (INGV-CT), said rapid advances in technology enable experts to use a wide range of methods to continually map and monitor Etna from a distance.

CNN: Keeping track of Etna's pulse