Conical Volcán Arenal is the youngest stratovolcano in  Costa Rica and one of its most active. The 1670-m-high  andesitic volcano towers above the eastern shores of Lake  Arenal, which has been enlarged by a hydroelectric  project. Arenal lies along a volcanic chain that has  migrated to the NW from the late-Pleistocene Los Perdidos  lava domes through the Pleistocene-to-Holocene Chato  volcano, which contains a 500-m-wide, lake-filled summit  crater. The earliest known eruptions of Arenal took place  about 7000 years ago, and it was active concurrently with  Cerro Chato until the activity of Chato ended about 3500  years ago. Growth of Arenal has been characterized by  periodic major explosive eruptions at several-hundred-year intervals and periods of lava effusion that armor  the cone. Arenal's most recent eruptive period began with a major explosive eruption in 1968. Continuous  explosive activity accompanied by slow lava effusion and the occasional emission of pyroclastic flows has  occurred since then from vents at the summit and on the upper western flank.   (Global Volcanism Program)  Arenal Location: 10.463° N, 84.7003° W Elevation: 1.657 m Photo: Rolf Cosar Photo: Rolf Cosar HOME