Activity increases at Semisopochnoi Posted by agimarc on 2015-03-29 Posted in: America N, Volcanoes. Tagged: Aleutian Islands, Caldera, Semisopochnoi, Tectonics. 40 Comments Semisopochnoi from Space – http://www.avo.alaska.edu/images/image.php?id=3134 Continue Reading Advertisement