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The Aigion-Neos Erineos coastal normal fault system (western Corinth Gulf Rift, Greece): Geomorphological signature, recent earthquake history, and evolution


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Palyvos, N.(a() , Pantosti, D.(a) , De Martini, P.M.(a) , Lemeille, F.(b) , Sorel, D.(c), Pavlopoulos, K.(d)
Journal of Geophysical Research B: Solid Earth
Volume 110, Issue 9, 4 September 2005, Pages 1-15

Type de document > *Article de revue

Mots clés > sûreté, faille/fracture, séismes

Unité de recherche > IRSN/DEI/SARG/BERSSIN

Auteurs > LEMEILLE Francis

Date de publication > 26/12/2005

Résumé

At the westernmost part of the Corinth Rift (Greece), an area of rapid extension and active normal faulting, geomorphological observations reveal the existence and geometry of an active NW-SE trending coastal fault system, which includes the Aigion fault. We recognize a similar fault pattern on both the coastal range front to the NW of Aigion town and the Holocene fan deltas in front of it. We interpret this as a result of recent migration of faulting to the hanging wall of the fault system. Differences in the geomorphic expression of the constituent faults provide hints on the possible evolution of the fault pattern during this recent migration. A trench excavated across one of the identified coastal fault scarps (on a Holocene fan delta) provides information on the seismic history of the fault system, which includes at least four (possibly six) earthquakes in the past 4000 years. A minimum estimate for the slip rate of the trenched fault is 1.9-2.7 mm/ yr. The trench exposed sediments of an uplifted paleolagoon (approximate age 2000 years B.P.), inside which the last two earthquakes formed an underwater monoclinal scarp. Oscillating coastal vertical movements are suggested by the fact that the lagoonal deposits are also uplifted on the trenched fault hanging wall (uplift by offshore faults) and by the abrupt transition from fluvial to lagoonal deposits (subsidence by more landward faults, assuming that extensive coastal sediment failure has not taken place in the specific part of the fan delta, within the time interval of interest). These movements suggest that the proposed migration of activity from the range front faults to those on the fan deltas is probably still ongoing, with activity on both sets of faults.

a- Seismology and Tectonophysics Department, Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, I-00143 Rome, Italy
b- Seismic Hazard Division, Institut de Radioprotection et de Surete Nucléaire, B.P. 17, F-92262 Fontenay-aux-roses Cedex, France
c- Centre d'Orsay, Université Paris-Sud XI, F-91405 Orsay Cedex, France
d- Faculty of Geography, Harokopion University, 70 El. Venizelou Str., GR-17671 Athens, Greece