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

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

Velocity models inferred from p-waves travel time curves in south Aegean

Με σκοπό τη δημιουργία μοντέλων ταχύτητας στην περιοχή του νοτίου Αιγαίου, χρησιμοποιούμε τις καταγραφές σεισμών κατά τη χρονική περίοδο από 1η Ιανουαρίου έως 3Ιη Αυγούστου 2005 από ένα νέο τηλεμετρικό δίκτυο που εγκαταστάθηκε και λειτουργεί στην περιοχή της Κρήτης. Τα μοντέλα ταχύτητας κατασκευάζονται από τις καμπύλες χρόνων διαδρομής των επιμηκών κυμάτων και χρησιμοποιούνται σε συνδυασμό με τις χρονικές διορθώσεις στο χρόνο άφιξης των σεισμικών κυμάτων σε κάθε σεισμολογικό σταθμό του δικτύου για τον ακριβή προσδιορισμό των εστιακών παραμέτρων των σεισμών που έχουν καταγραφεί στην περιοχή του νοτίου Αιγαίου με τη χρήση του προγράμματος HYPOINVERSE. Συνδυάζοντας όλες τις διαθέσιμες πληροφορίες από τη βιβλιογραφία και τα αποτελέσματα της παρούσας μελέτης προσδοκούμε να συμβάλουμε στην αποσαφήνιση του σεισμοτεκτονικού προτύπου της περιοχής καθώς και της γεωμετρίας της καταδυόμενης λιθόσφαιρας της ανατολικής Μεσογείου.The seismicity recorded during Ist January to 31st August 2005 from a new telemetry network installed and operating on the island of Crete, is used in an effort to obtain new velocity models for the area of south Aegean. The models are constructed from the P-waves travel time curves and are later used for the events relocation with the HYPOINVERSE algorithm and station delays calculation. Furthermore, results are discussed and compared with the ones derived from other significant previous works presented the last years. We anticipate by combining all the available information from the literature and the analysis of our data set to contribute to the seismotectonic modeling of the study area and to construct a most complete image of the geometry of the subducted plate