The Ghegham Volcanic Ridge, located in west-central Armenia between the capital city of Yerevan and Lake Sevan, contains as many as 127 volcanic centers, lava domes and pyroclastic cones, of Pleistocene-to-Holocene age. The volcanoes and associated lava flows cover a 65-km-long, 35-km-wide area west of Lake Sevan and south of the Hrazdan River and are concentrated along three NNW-SSE-trending alignments. Lava flows from the central and eastern clusters flowed into Lake Sevan. Initial explosive eruptions in the volcanic field were followed by the extrusion of rhyolitic obsidian lava domes and flows. The latest activity produced a series of andesitic and basaltic andesite cinder cones and lava flows. The central and eastern portions of the field contain large areas of Holocene eruptions with morphologically fresh lava flows devoid of vegetation.