At the South-West end of Lesvos, in the area of Chroussos, is the volcanic dome of Aetos, Chroussos. It is an impressive dome-shaped volcanic hill characterized by steep slopes.
The volcanic edifice of Chrousos is a volcanic dome, the creation of which is linked to the upward movement of magma, which penetrated the volcanic formations. The magma moved upward through a volcanic conduit connecting the magma chamber to the surface. As the igneous material ascended to the surface, it penetrated the overlying andesitic and dacite mantle geological layers, and with the gradual loss of gases, the magma began to lose its strength, solidifying at a shallow depth without causing a volcanic eruption .Over geological time, the rocks that surrounded the solidified magma were eroded, resulting in the appearance of the impressive structure of Chrousos, which characterizes the landscape