Near-source high-rate GPS, strong motion and InSAR observations to image the 2015 Lefkada (Greece) Earthquake rupture history.

ABSTRACT: The 2015/11/17 Lefkada (Greece) earthquake ruptured a segment of the Cephalonia Transform Fault (CTF) where probably the penultimate major event was in 1948. Using near-source strong motion and high sampling rate GPS data and Sentinel-1A SAR images on two tracks, we performed the inversion for the geometry, slip distribution and rupture history of the causative fault with a three-step self-consistent procedure, in which every step provided input parameters for the next one. Our preferred model results in a ~70° ESE-dipping and ~13° N-striking fault plane, with a strike-slip mechanism (rake ~169°) in agreement with the CTF tectonic regime. This model shows a bilateral propagation spanning ~9?s with the activation of three main slip patches, characterized by rise time and peak slip velocity in the ranges 2.5-3.5?s and 1.4-2.4?m/s, respectively, corresponding to 1.2-1.8?m of slip which is mainly concentrated in the shallower (<10?km) southern half of the causative fault. The inferred slip distribution and the resulting seismic moment (M₀?=?1.05?×?10¹⁹ N m) suggest a magnitude of M _w 6.6. Our best solution suggests that the occurrence of large (M _w ?>?6) earthquakes to the northern and to the southern boundaries of the 2015 causative fault cannot be excluded.

SUBMITTER: Avallone A 

PROVIDER: S-EPMC5583176 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature