emplaced by one or more pyroclastic flows, possibly associated with formation of Caldera Two. Post-Caldera Two deposits are mainly lava flows. Two relatively recent aa flows have well developed levees; one originated from the breached central crater of Little Sitkin volcano, and the other from a fissure along the western trace of the Caldera One boundary fault. On June 23, 2014, a magnitude 7.9 earthquake struck near the island. Citizens were ordered to evacuate. Tsunami warnings were soon issued. Flora and fauna Vegetation is mainly low leafy plants, moss, sedge and grass that grows extensively in altitudes below , with very few woody plants. There has historically been a population of Arctic foxes, which numbered 250 in 1930, subsisting on echinoderms, snails, and insects. Small populations of sea birds and marine invertebrates have also been found. See also List of volcanoes in the United States References External links Little Sitkin Photos Photographs from Little Sitkin Island, July 2008 Rat Islands Volcanoes of Alaska Calderas of Alaska Stratovolcanoes of the United States Islands of Alaska Islands of Unorganized Borough, Alaska Volcanoes of Unorganized Borough, Alaska Landforms of Aleutians West Census Area, Alaska Pleistocene calderas Pleistocene stratovolcanoes Holocene stratovolcanoes