Geomorphological and geological observations at the coast of Tripiti Hill (Heraklion Harbour, Crete), in relation to reported active faulting

Heraklion is a fast-growing urban centre where knowledge of active faulting is necessary for city planning and infrastructure projects. Neotectonic faults (not all necessarily active at present) most probably traverse the built-up coastal part of Heraklion, but they require subsurface geological and geophysical studies to be precisely located and characterised. In the frame of a research project assigned to the Institute of Geodynamics by the Heraklion Municipality, we made detailed geomorphological and geological observations in the coastal area of the Tripiti Hill, where previous workers report a NNW-SSE trending, WSW-dipping, presently active normal fault crossing the port of Heraklion as well as a densely built-up part of the city. Based on our observations, we conclude that this fault does not exist. In support of our conclusion, we discuss: (1) the nature of a steep contact between Neogene bedrock and Quaternary deposits exposed at a roadcut along the coastal avenue, (2) the depositional environment of Quaternary deposits at the above outcrop and surrounding area, (3) the buried relief and stratigraphic features exposed in a trench excavated by previous workers across the alleged fault trace, and (4) the geomorphological context of coastal deposits and marine terrace remnants used by previous workers for fault slip rate estimation. This case study is presented as a vivid example of the importance Geomorphology and Quaternary Geology have in studies of active faulting.