The 2014 Kefalonia Doublet (Mw6.1 and Mw6.0), central Ionian Islands, Greece: Seismotectonic implications along the Kefalonia transform fault zone

Abstract

The 2014 Kefalonia earthquake sequence started on 26 January with the first main shock (Mw 6.1) and aftershock activity extending over 35 km, much longer than expected from the causative fault segment. The second main shock (Mw 6.0) occurred on 3 February on an adjacent fault segment, where the after-shock distribution was remarkably sparse, evidently encouraged by stress transfer of the first main shock. The aftershocks from the regional catalog were relocated using a 7-layer velocity model and station residuals, and their distribution evidenced two adjacent fault segments striking almost N-S and dipping to the east, in full agreement with the centroid moment tensor solutions, constituting segments of the Kefalonia Transform Fault (KTF). The KTF is bounded to the north by oblique parallel smaller fault segments, linking KTF with its northward continuation, the Lefkada Fault.