The central Ionian Islands area, including Kefalonia and Lefkada Islands constitutes an area with the highest seismic hazard in Greece. Lefkada Island has experienced two strong (M > 6.0) earthquakes in 2003 (M W 6.2) associated with a fault segment in the northwestern part of the Island, and in 2015 (M W 6.5), associated with the adjacent southern fault segment, both aligned along the western coastline. The close temporal proximity along with the ongoing high seismic activity motivated our investigation. Microseismic data were relocated over a period of more than 4 years, following the 2015 mainshock resulting in a comprehensive seismic catalog and the determination of 110 focal mechanisms for the stronger events. A density-based clustering algorithm (DBSCAN) was applied to the relocated hypocenters and focal mechanisms, enabling improved association of seismicity patterns with the kinematic properties of the fault zone. The effects of the 2015 mainshock on regional seismicity were assessed through coseismic static stress changes, calculated using a variable slip model derived from a joint inversion of regional and teleseismic seismic data, combined with geodetic displacement estimates. Stress inversion of the calculated focal mechanisms identified faults prone to instability, which were used as receiver faults in the stress change analysis. The results reveal that post-2015 seismicity was strongly influenced by the mainshock, with clusters aligning along the primary fault zone as well as secondary structures within a rather narrow faulting zone. These findings enhance understanding of the seismic behavior of the Kefalonia Transform Fault Zone and its secondary faults, providing critical insights for seismic hazard assessment in this tectonically active region. • Relocated microseismicity reveals active fault structures in Lefkada Island. • Clustering of earthquakes and focal mechanisms aids structural interpretation. • Joint inversion yields a variable slip model for the 2015 Mw6.5 mainshock. • Static stress changes explain post-seismic clusters along fault structures.

The cooling and exhumation history of orogens along subduction systems provides unique constraints on regional tectonic evolution, reflecting the interplay between crustal deformation and plate convergence dynamics. Southern Ecuador lies within a transitional zone between the northern and central Andes, where contrasting tectonic histories have generated variations in inherited crustal architecture that influence how regional plate-boundary forcing is expressed in the upper plate. We present new apatite fission-track thermochronology data from seventeen plutonic rock samples across five crustal blocks in southern Ecuador: Western Cordillera, Eastern Cordillera, Intermontane basins, Celica-Lancones, and Amotape-Tahuin. Our results show that cooling ages are internally consistent within each block but differ across them, revealing a pattern of diachronous exhumation in most blocks. Some blocks instead record pronounced post-magmatic cooling, suggesting shallow pluton emplacement. Thermal history modeling, based on good-fit time–temperature paths indicates that regional exhumation initiated in the middle Eocene and persisted thereafter. The cooling trajectories group into three distinct, albeit partially overlapping, intervals: ~45–38 Ma (middle - late Eocene), ~40–30 Ma (late Eocene – early Oligocene), and ~ 33–25 Ma (Oligocene). We interpret this protracted and spatially variable exhumation as reflecting changes in the boundary conditions of the subduction system, including a transition from oblique to more orthogonal convergence and increases in convergence rates during the Cenozoic. However, the observed spatial variability is more directly linked to the progressive re-activation of major fault systems and, locally, to magmatic activity. • New thermochronological data reveal diachronous exhumation in Southern Ecuador. • Thermal modeling identifies three main cooling phases. • Exhumation reflects shifts in subduction dynamics and is influenced by with fault-controlled deformation.

While proximal domains in rifted margins are commonly associated with moderate crustal thinning, those developed along ancient orogenic belts, for example,can show more complex architectures influenced by pre-existing heterogeneities. Here, the interplay between inherited and rift-related structures is crucial, contributing to the complexity of these proximal marginal domains. This study investigates the role of pre-existing Gondwana structures in the development of a proximal breakaway complex, and the formation of a V-shaped basin within the Cretaceous Campos Basin. We use seismic reflection data and potential-field maps to characterize the structural framework of the study area. By combining observations regarding basement morphology, fault systems, and intracrustal reflectors, with gravity and magnetic sources, the study proposes a three-segment structural model (north, central, south) for the central Campos proximal domain. Wediscuss the reactivation of pre-existing basement fabric that led to the exhumation ofa middle ductile crust coeval to a localized shift of depocenters in the Barremian. These processes influenced the spatial distribution of faults and the development of a secondary WNW-ESE transfer zone, as well as the opening of a V-shaped basin associated with adome-shaped Central High. This study delineates a boundary for the Campos proximal domain and discusses, for the first time in the Campos Basin, the opening of a V-shaped basin as a result of differing vertical mechanical behavior combined with a sequence of tectonic reactivations of pre-existing basement structures. This contribution aims at enhancing our understanding of structural responses of a heterogeneous crust during the initial stages of rifting. • We characterized a proximal breakaway complex at the central Campos rifted margin. • ⁠Pre-existing basement fabric reactivation drove middle crust exhumation. • ⁠Rift structures include a minor E-W transfer zone and detachment faults. • Tectonic reactivations led to shifting depocenters and opening of a V-shaped basin.