Flores Island and Corvo Island to its north are located far west of the rest of the Azores islands and are the only two Azorean volcanoes lying west of the Mid-Atlantic Ridge. Growth of an initially submarine volcano included Pleistocene explosive activity associated with formation of small calderas. The 10 x 15 km island of Flores is dotted by numerous pyroclastic cones and craters. Following a long period of quiescence beginning about 200,000 years ago, several young phreatomagmatic craters and associated lava flows were erupted during the Holocene, including two about 3000 years ago. The Caldeira Funda de Lajes tuff ring formed about 3150 years ago, accompanied by a lava flow that traveled to the SE, reaching the coast at Lajes. The Caldeira Comprida tuff ring in Caldeira Seca, west-central Flores, erupted about 2900 years ago. It produced a lava flow that traveled NW-ward and reached the coast at Faja Grande.