Haralambos Kranis

Structure and evolution of the western Corinth Rift, through new field data from the Northern Peloponnesus

Abstract Extensional structures with geometrical and kinematic features analogous to the known Gulf of Corinth faults, are found further to the south of what is considered to be the southern margin of the of Proto-Corinth Gulf, reaching south to the northern flanks of Mt Mainalon. This mountain front is marked by the North Mainalon Fault Zone, which comprises a series of normal fault segments with NNE dips. Assuming a listric or ramp-flat geometry for the North Mainalon Fault Zone, it could flatten at a depth of 6–8 km, underneath Mt Khelmos. Its southern, shallow part has been truncated by NNE- and NNW-trending faults, which may be linked to northward propagation of the east–west extension in the Southern Peloponnesus, causing further uplift in the central and northern Peloponnesus, while its deeper part is still active and may reach further north and sole onto the hypothesized detachment zone beneath the Gulf of Corinth.

Egio earthquake (15 June 1995): An episode in the neotectonic evolution of Corinthiakos Gulf

Abstract Egio earthquake (15 June 1995) produced a series of destructive geological surficial effects in northern Peloponnessos and southern Sterea Hellas. After a brief review on the current opinions on the tectonic regime of the area has been made, we give a description of these effects, focusing mainly on the fractures along the Egio fault. Then, we present a model to interpret the earthquake activity of 15 June 1995; finally a discussion concerning the extensional tectonic regime of the area is made based on seismic data, the geometry of onshore and the recently described offshore faults.

PALEOSEISMIC EVENTS RECORDED IN PLEISTOCENE SEDIMENTS IN THE AREA OF KALAMATA (PELOPONNESSOS, GREECE)

Abstract Two localities of sedimentary deformation in the Kato Messinia sub-graben (Kalamata area) are examined. In both cases Early (or Middle) Pleistocene sedimentation was disrupted possibly by earthquakes. A comparison is also made between tectonic activity at the eastern margin and within the Kato Messinia graben. The study of these two cases shows that the current tectonic regime has been established at least since Early Pleistocene.

Building up or out? Disparate sequence architectures along an active rift margin—Corinth rift, Greece

Early Pleistocene synrift deltas developed along the southern Corinth rift margin were deposited in a single, dominantly lacustrine depocenter and were subject to the same climate-related base-level and sediment supply cyclicity. Two synrift deltas, just 50 km apart, show markedly different sequence geometry and evolution related to their location along the evolving border fault. In the west, strongly aggradational fan deltas (>600 m thick; 2–4 km radius) deposited in the immediate hanging wall of the active border fault comprise stacked 30–100 m thick stratal units bounded by flooding surfaces. Each unit evolves from aggradational to progradational with no evidence for abrupt subaerial exposure or fluvial incision. In contrast, in the central rift, the border fault propagated upward into an already deep lacustrine environment, locating rift-margin deltas 15 km into the footwall. The deltas here have a radius of >9 km and comprise northward downstepping and offlapping units, 50–200 m thick, that unconformably overlie older synrift sediments and are themselves incised. The key factors driving the marked variation in sequence stratigraphic architecture are: (1) differential uplift and subsidence related to position with respect to the border fault system, and (2) inherited topography that influenced shoreline position and offshore bathymetry. Our work illustrates that stratal units and their bounding surfaces may have only local (<10 km) extent, highlighting the uncertainty involved in assigning chronostratigraphic significance to systems tracts and in calculating base-level changes from stratigraphy where marked spatial variations in uplift and subsidence occur.

Rapid spatiotemporal variations in rift structure during development of the Corinth Rift, central Greece: Rapid Changes in Rift Structure, Corinth

The Corinth Rift, central Greece, enables analysis of early rift development as it is young (<5 Ma) and highly active and its full history is recorded at high resolution by sedimentary systems. A complete compilation of marine geophysical data, complemented by onshore data, is used to develop a high-resolution chronostratigraphy and detailed fault history for the offshore Corinth Rift, integrating interpretations and reconciling previous discrepancies. Rift migration and localization of deformation have been significant within the rift since inception. Over the last circa 2 Myr the rift transitioned from a spatially complex rift to a uniform asymmetric rift, but this transition did not occur synchronously along strike. Isochore maps at circa 100 kyr intervals illustrate a change in fault polarity within the short interval circa 620–340 ka, characterized by progressive transfer of activity from major south dipping faults to north dipping faults and southward migration of discrete depocenters at ~30 m/kyr. Since circa 340 ka there has been localization and linkage of the dominant north dipping border fault system along the southern rift margin, demonstrated by lateral growth of discrete depocenters at ~40 m/kyr. A single central depocenter formed by circa 130 ka, indicating full fault linkage. These results indicate that rift localization is progressive (not instantaneous) and can be synchronous once a rift border fault system is established. This study illustrates that development processes within young rifts occur at 100 kyr timescales, including rapid changes in rift symmetry and growth and linkage of major rift faults.