Historical faulting in Aghios Konstantinos area (central Greece), based on archaeological indications

Aghios Konstantinos lies on the foothills of the Atalanti fault system scarps. The area is located in central Greece and the fault system is the primary morphology-controlling agent. It defines the west shoreline of northern Euboea gulf and is associated with several historical earthquakes.
   Morphologically this zone forms steep high bedrock scarps, on the foot of which extensive colluvial deposits are observed. Several minor fault scarps have been mapped and they were classified in three classes: a) bedrock fault scarps with visible fault plane, b) softsediment scarps with visible fault plane and c) soft-sediment scarps with no visible fault plane. The minor scarps are generally aligned in en échelon pattern, following the general WNW – ESE trend of the major fault zones, while their general dip direction is towards the NNE. Fault analysis shows that there is extensive tilting of hangingwall blocks, as well as of the minor faults themselves. Faults tend to “lock” with each other forming a complex pattern that is inherited to the overlying Upper Miocene-Pleistocene and Holocene sedimentary cover.
   A small settlement was found at “Karvouna” site, west of Aghios Konstantinos, during the works performed for the construction of a new segment of E75 highway. This settlement comprises of low-lying houses, storage rooms and a small temple. A larger and more important temple was discovered in another location nearby. According to archaeological evidence, the settlement was active in classical and Hellenistic times, and sporadically afterwards. It was a rural settlement and numerous finds indicate at least three successive layers of buildings with stone foundations criss-crossing one another with no particular pattern.
   The foundations of the buildings and the surrounding environs show many signs of episodic deformation, either direct or indirect. The most obvious cases are:
   A surface rupture cutting through at least two foundations. It has a heave of up to 3 cm and a slight normal displacement.
   Several basal walls and foundations have been found tilted and deformed. Tilting is as high as 30^º off vertical.
   A small temple that is located just outside the settlement shows signs of sudden destruction: roof tiles are being found in and around the temple. They are roughly retaining the space that they had on the roof, which is an indication that the wooden roof collapsed. Also, one of the entrance pillars seems displaced both vertically as well as left-laterally. This displacement vector is compatible with the general fault displacement vector in the area.
   An artificial cross-section at the stream that bisects the settlement shows an exposure of a normal fault system that deforms a series of paleoseoils and runs through the settlement, parallel to the main fault. Paleoseismological analysis of the cross-section shows that this fault system was not active in historical times, although the southwesternmost strand of the system roughly coincides with the surface rupture.
   The position of the settlement on a rather steep slope, as well as the nature of finds, indicate a severe topographical amplification of the effects. Nevertheless, we believe that the primary deformational cause was faulting, evidence of which has been found in the crosssection that was consequently amplified by gravitational effects.