Alterations of sandstone and clay geological formations, typical of Lemnos’s molassic deposits, are found northwest of the Plaka settlement, in the area of Saint Charalambos. A large fault cuts through the area’s geological layers of sedimentary rocks.

It is a normal fault with a NW-SE direction. The fault runs along the beach, right next to the steps leading down to the church’s holy water, where the movement of the geological formations on the vertical slope may be seen.

The evidence of rock movement is visible on the surface of the fault as fractures known as striations. These tectonic lines were formed by the friction of the rocks in their parallel movement and provide crucial information about the fault’s seismic activity in the past.