Rupture process of the 2014 Cephalonia, Greece, earthquake doublet (Mw6) as inferred from regional and local seismic data

Asperity break after 12 years: The Mw6.4 2015 Lefkada (Greece) earthquake

“…As the quality and quantity of the seismological data increase, especially with the installation of many stations in the aftermath of recent earthquake sequences, it can be clearly seen that the strong events depicting the presence of the CTF are very close to the coastline, and, in a number of cases their foci are situated underneath the Lefkada and Cephalonia Islands [ Sokos et al ., , and references therein]. The 2003 and 2015 strong events clearly define the position of LS on land or very close to the western coast of the Lefkada Island.…”

“…In the region between the Lefkada and Cephalonia Islands, where the bathymetry depth contours become steeper and curved, the clusters of aftershocks tend to align along an approximately EW trend. In this area, similar aftershock clusters were observed during the Lefkada 2003 and Cephalonia 2014 earthquake sequences [ Karakostas et al ., ; Sokos et al ., ], see Figure b. These observations suggest the existence of a system of parallel strike‐slip faults, called strike‐slip duplexes [ Woodcock and Fischer , ] that form an extensional duplex transfer zone between LS and CS.…”

“…Altogether, the episodes in 2003 and 2015 ruptured the entire ~40 km of the Lefkada Segment. Eventually, including also our previous study of the Cephalonia earthquake sequence of 2014 [ Sokos et al ., ], we discuss our findings in terms of the local seismotectonics and reconsider the position of the CTF.…”

A New Strategy to Compare Inverted Rupture Models Exploiting the Eigenstructure of the Inverse Problem

“…We perform the first tests on the inversion results obtained with the method of Gallovič et al (2015), a linear-inversion method with multitime window parameterization, unconstrained rupture speed and rise time, constrained total rupture duration (12 s or less), and two regularization constraints: a k −2 slip covariance function (k being the wavenumber) and positivity of slip rate (see also Sokos et al, 2015). The degree of smoothing is controlled by a parameter σ D defined by Gallovič et al (2015).…”

Earthquake Triggering Effect Scenarios During the 2014 Sequence in Cephalonia and 2015 Earthquake in Lefkada Broader Areas, Ionian Sea, Greece

“…Slip version analysis suggests rupture initiation at the upper central part of the fault plane . The analysis of Sokos et al (2015) cannot be compared as they used a 2-segment fault model for the February 3 event. and F4, set as source faults) on faults (receiver faults) with geometric and kinematic attributes similar to i) the three segments of the southern part of the CTFZ system (GRIS620, GRIS621 and GRIS622) represented by common parameters, ii) the "Lefkada" (GRIS623) fault, iii) the "Assos-Skala" (GRIS625) fault, and iv) the "Kastos" (GRIS628) fault.…”