Volcanoes, thermal springs and caves
Geology of Methana
Methana is one of the youngest volcanic areas in the western part of Greece and its 30-32 volcanoes* are still determined as "active". There are many lava domes and lava flows around the volcanic centre. The thermal springs, gases and rare small earthquakes show that in future there may be new eruptions.
The peninsula belongs to the western serial of active volcanoes in the Aegean arc. The volcanoes of Methana (Poros, Egina, Sousaki), Milos, Santorin and Nisyros are the active parts of the subduction of the plates that are pushed from north Africa below Europe and little Asia. All these volcanoes are defined as active. Eruptions in future are possible.
The Methana volcanoes differ a lot from the famous volcanoes of Santorini (Koloumbos & Kameni islands). There are mostly lava domes. A good sample of an active volcano like this, you may find on Tom Pfeiffer´s website http://www.VolcanoDiscovery.com about Kelut volcano in Indonesia.
*(Of course the entire volcano peninsula is ONE volcano, but we say this traditionally for every former eruption centre).