[4] Other volcanic features in the area include breccia, lahar deposits, lava flows and tuffs.

[1][5] It is constructed within the andesitic Monteverde Formation,[5] which was erupted between 2.1 and 1 million years ago.

[4] Hot springs, mud pots and deposits of sulfur are found both at the lake and near the Río Penas Blancas.

[4] The active volcano Arenal lies north-northwest of Laguna Poco Sol.

[5] Arenal along with Cerro Chato between Arenal and Laguna Poco Sol and Cerro Pocosol south of Laguna Poco Sol may be located along a zone of tectonic weakness that was accompanied by northeast-migrating volcanism.