The Eurotas River occupies the floor of a rift valley, or graben, created by extensional forces acting over the Hellenic Plate in a northeast-southwest direction. The corresponding fault-block mountains are the Taygetus Massif on the west and the Parnon Massif on the east - both limestone ridges derived from a former sea bed. On the east side of Taygetus is the Sparta Fault, a normal fault, which strikes in a zig-zag path along the foot of the massif and dips toward the interior of the valley. The river is on the western side. From it the scarps of the footwall of the Sparta Fault are visible at the base of Tayegetus.