On 26 January 2014 at 13:55 UTC, an Mw 6.0 earthquake struck the island of Cephalonia, Greece, followed five hours later by an Mw 5.3 aftershock and by an Mw 5.9 event on 3 February 2014 at 03:08 UTC (National Observatory of Athens, Institute of Geodynamics [NOA-GI]). The epicenter of theMw 6.0 event was relocated 2 km east of the town of Lixouri, and that of the Mw 5.9 event at the tip of the Gulf of Argostoli, in the northern part of the Paliki peninsula (Fig. 1; Karastathis et al., 2014; Papadopoulos et al., 2014). Extensive structural damage and widespread environmental effects were induced throughout the Paliki peninsula and along the eastern coast of the Gulf of Argostoli (Valkaniotis et al., 2014). Quays, sidewalks, and piers were damaged in the waterfront areas of the towns of Lixouri and Argostoli, the island capital, and liquefactions, road failures, rock falls, and small landslides were observed.Most of the latter effects took place in the aftermath of the 26 January 2014 event and were reactivated one week later by the 3 February earthquake. In this paper, we derive the 3D surface deformation field associated with the 3 February 2014Mw 5.9 event based on the application of three different measurement techniques to Synthetic Aperture Radar (SAR) acquisitions from the Italian Space Agency (Agenzia Spaziale Italiana [ASI]) COSMO– SkyMed satellites and the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR) Tan- DEM-X satellite. We then model the main seismic sources and their associated slip distributions, comparing the latter with improved hypocenter relocations, which allows us to speculate on the possible rupture mechanism. Finally, we discuss the contribution of our findings to the characterization of the seismogenic sources of this region
SUMMARY. A comparison is performed between predictions of coseismic and post-seismic deformations, based on two different earth models. The main purpose of thi
In the Eastern Alps, the indentation of the Adriatic promontory since the Cenozoic affected the kinematics of separate crustal domains bounded by faults that accommodate lateral extrusion processes and differential shortening. Deciphering the pattern of crustal stresses in the orogen interior is challenging, due to the lack of in situ stress measurements at crustal depths. We define stress regimes and the orientations of the most‐compressive horizontal stress (SHmax) by integrating published results with new data, including stress analysis from fault plane solutions, estimation of crustal anisotropy through the shear wave splitting analysis, paleostress determination from fault slip data, and computation of cumulative seismic displacements. The retrieved regional SHmax are generally consistent with N‐S convergence. In the northern part of the study area, current stress orientations are almost parallel to paleo‐SHmax, suggesting a rather uniform compressional regime since the late Cenozoic. Conversely, sharp deflections and divergence with paleo‐SHmax appear at the western border of the Adriatic promontory across major transpressive and extensional shear zones and in the Southalpine domain, indicating a change in tectonically induced second‐order stresses. A current strike‐slip regime with subordinate orogen‐parallel seismic displacements affects a belt to north of the Periadriatic Lineament and NE‐extension characterizes the Ortles‐Engandine region. Seismic anisotropy locally exhibits fault‐parallel fast axes (Brenner‐Giudicarie fault‐systems, Dinaric and Southalpine thrusts), whereas stress‐induced anisotropy parallel to SHmax characterizes the southern part of the orogen. Cumulative seismic displacements are small compared to geodetic ones, and unravel partitioning of deformation into second‐order transpressive and extensional belts in response to indentation.
We use Interferometric Synthetic Aperture Radar (InSAR) to study the Cephalonia–Lefkada Transform Fault Zone (CTF) in the Ionian Sea. The CTF separates continental subduction to the north from oceanic subduction to the south, along the Hellenic Subduction Zone. We exploit a rich multi-modal radar dataset of the most recent major earthquake in the region, the 17 November 2015 Mw 6.4 event, and present new surface displacement results that offer additional constraints on the fault segmentation of the area. Based on this dataset, and by exploiting available information of earthquake relocation, we propose a new rupture process for the 2015 sequence, complementary to those published already. Our modelling includes an additional southern fault segment, oblique to the segment related with the mainshock, which indicates that the CTF structure is more complex than previously believed.
The active collision of the Apulian continental lithosphere with the Eurasian plate characterizes the tectonics of the Epirus region in northwestern Greece, invoking crustal shortening. Epirus has not experienced any strong earthquakes during the instrumental era and thus there is no detailed knowledge of the way the active deformation is being expressed. In March 2020, a moderate size (Mw 5.8) earthquake sequence occurred close to the Kanallaki village in Epirus. The mainshock and major aftershock focal mechanisms are compatible with reverse faulting, on NNW-ESE trending nodal planes. We measure the coseismic surface deformation using radar interferometry and investigate the possible fault geometries based on seismic waveforms and InSAR data. Slip distribution models provide good fits to both nodal planes and cannot resolve the fault plane ambiguity. The results indicate two slip episodes for a 337° N plane dipping 37° to the east and a single slip patch for a 137° N plane dipping 43° to 55° to the west. Even though the area of the sequence is very close to the triple junction of western Greece, the Kanallaki 2020 activity itself seems to be distinct from it, in terms of the acting stresses.