HELIKE MARINE TERRACES

The footwall of the Helike fault is occupied by fan delta conglomerate of lower Pleistocene age formerly deposited in a subsiding hangingwall and currently uplifted. Superimposed on the uplifted conglomerates are more recent late Quaternary marine deposits, formed during sea level high stands. (Fig. 4.1) The uplifted platforms based on dated material are correlated with highstands of the eustatic sea level by Chappel et al 1996.  (Fig. 4.2)

A max of 8-9 terraces were identified in the eastern Helike fault segment. The max terrace elevation is 525m. The average Pleistocene uplift rate estimated for the Helike fault is 1.1 mm/year. This uplift rate produces fault slip rates of 3.5 ā€“ 6.5mm/year contributing 2,5 ā€“ 4mm/year extension across the Gulf. If the uplifted rate for the Holocene is taken as 2mm/year (Stewart 1996) then the max extension is 5-7 mm/yr across the Gulf. These extension rates are significantly lower than the total extension across the western Gulf, of 10 to 15mm/year for the last 20 years as measured by GPS. It is suggested therefore that significant strain is accommodated by offshore faults.  (Stefatos et al 2002)

 

 

References:

Chappell J., Omura A., Esat. T., McCulloch, M., Pandolfi, J., Ota, Y., Pillans, B. 1996. Reconciliation of late Quaternary sea levels derived from coral terraces at Huon Peninsula with deep sea oxygen isotope records. Earth Planetary Science Letters 141: 227-236

McNeill L. & Collier R. 2004. Uplift and Slip rates of the eastern Helike fault segment, Gulf of Corinth Greece, inferred from Holocene and Pleistocene Terraces. J. of the Geological Society of London 161:81-92.

McNeill L. & Collier R., Pantosti D., De Martini P., Dā€™ Addezio G., 2006. Recent History of the Eastern Helike Fault: Geomorphology, Paleoseismology and impact on Paleoenvironments. Ancient Helike and Aigialeia: Archaeological Sites in Geological Active Regions (Eds D. Katsanopoulos, S. Soter and I. Koukouvelas). Proceedings of the 3rd Intern. Conference on Helike III  pp 243-265.

Stewart I. 1996. Holocene uplift and Palaeoseismicity on the Eliki Fault, western Gulf of Corinth, Greece. Annali di Geophysica 39:575-588

 

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