It has a destroyed crater to the northwest.[2] Prehistoric lava flows on its western flank;[1] one of them, the so-called Florida flow, was perhaps created by Platanar's most recent activity. Cerro Porvenir has a truncated caldera at the summit with a cone inside.[2] Both of these are part of a composed stratovolcano of Upper Pleistocene age that on Platanar's side overlies the remains of Palmera's collapsed caldera, of probable late Pleistocene age.[3] Platanar has erupted lavas ranging from basalts to andesites in composition.[2]
Social and economic activities
The western flanks of both volcanoes are used for dairy farming.[4] In 1968 2,500 hectares (6,200 acres) on Cerro Platanar were converted into a National Forest.[5]
Recent activity
On 30 March 1997 there were six earthquakes on the south flank, the strongest being of magnitude 2.7. A previous seismic swarm in April 1980 had lasted for 2–3 weeks.[6]
