The 2006 Kythira (Greece), Mw6.7 slab-pull event: tectonic implications and the geometry of the hellenic wadati-benioff zone

Abstract

A strong (Mw=6.7) intermediate depth earthquake occurred on 8 January 2006 (11:34 UTC) in southwestern Aegean Sea (Greece) causing limited damage to structures on the nearby islands of Kythira and Antikythira, as well as western Crete Island. The epicentral area belongs to the SW segment of the Hellenic Arc, which is known to be associated with the occurrence of large shallow and intermediate depth earthquakes, mainly due to the subduction of the Eastern Mediterranean oceanic lithosphere under the Aegean microplate. The main shock occurred on a dextral strike slip fault at a depth of 75 km, within the descending slab, as it is revealed by both, the spatial distribution of the accurately located aftershocks and its fault plane solution determined in the present study and implying a slab-pull event. The aftershock activity from 8 to 31 January 2006 is distributed in depths ranging from 55 to 75 km, and being comprised in an almost rectangular and vertical plane with a length equal to 28 km and a width of 20 km, which adequately defines the dimensions of the rupture area. The geometry of the Wadati-Benioff zone in this area, namely the southwestern part of the Hellenic Arc, is explored by an exhaustive analysis of all the available phase arrivals gathered from the International Seismological Centre, and the relocation of the earthquakes occurred since 1964 in the South-West Aegean region.

Multi-temporal SAR interferometry for monitoring ground deformation in Greece

“…The western part of the Hellenic arc, where the epicenter is located, accounts for over 60% of the seismic-energy release in Europe (Karakostas et al, 2006). The seismic event of January 8, 2006 with an epicenter in the southwestern part of the Hellenic Arc (Nikolintaga et al, 2008), along with further seismic activity, associated with the Kythira fault during the 20 ℎ century (Karakostas et al, 2006), triggered the analysis of this section on deformation monitoring in Kythira island. Similar to Amorgos case study, described in Section 4.2 time-series analysis of more than a decade was performed, aiming to provide important insights on Kythira's tectonic activity and its association with the latest earthquake.…”