The Azuma volcanic group consists of a cluster of stratovolcanoes, shield volcanoes, lava domes, and pyroclastic cones.  The andesitic and basaltic complex was constructed in two E-W rows above a relatively high basement of Tertiary sedimentary rocks and granodiorites west of Fukushima city.  Volcanic activity has migrated to the east, with the Higashi-Azuma volcano group being the youngest.  The symmetrical Azuma-Kofuji crater and a nearby fumarolic area on the flank of Issaikyo volcano are popular tourist destinations.  The Azuma complex contains several crater lakes, including Goshiki-numa and Oke-numa.  Historical eruptions, mostly small phreatic explosions, have been restricted to Issaikyo volcano at the northern end of the Higashi-yama group.