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Duni, Llambro
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Duni, Llambro
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- PublicationOpen AccessActive tectonics and fault evolution in the Western Balkans(2022-08-17)
; ; ; ; ; ; ; ; ; ; ; ; ;The western Balkans occupy a region influenced by two major active tectonic processes: the collision between the Adriatic Region and the Dinarides in the west, and the extension of the Aegean Region and its surroundings as they move towards the Hellenic Trench. An understanding of the kinematics and dynamics of the western Balkans has significance for our understanding of continental tectonics in general, and is the object of this paper. The region is rich in observational data, with many well-studied earthquakes, good geodetic coverage by GNSS (Global Navigation Satellite System) and abundant exposure of active faulting and its associated geomorphology, especially within the Mesozoic carbonates that cover large sectors of the extensional areas. We first use such observations to establish the regional kinematic patterns, by which we mean a clarification of how active faulting achieves the motions observed in the deforming velocity field obtained from GNSS measurements. We then use geomorphological observations on the evolution of drainage systems to establish how kinematic and faulting patterns have changed and migrated during the Late Neogene-Quaternary. The kinematics, and its evolution, can then be used to infer characteristics of the dynamics, by which we mean the origin and effect of the forces that control the overall deformation. The principal influences are: (i) the distribution and evolution of gravitational potential energy (GPE) contrasts arising from crustal thickness variations and elevation, in particular the growth of topography by shortening in the Albanides–Hellenides mountain ranges and the high elevation of mainland Greece relative to the Mediterranean seafloor and (ii) the ability of the boundaries of the region, along the Adriatic coast and in the Hellenic Trench, to support the forces arising from those GPE contrasts. The evolution in space and time indicates an interaction between the anisotropic strength fabric of the upper crust associated with faulting, and the more distributed and smoother patterns of flow that are likely to characterize the ductile deformation of the lower, aseismic part of the lithosphere—both of which influence the deformation on the scale of 100–200 km. The persistent argument about whether continental deformation is best described by a continuum or by rigid-block motions is largely a matter of scale and particular location: both are influential in establishing the patterns we see.66 13 - PublicationRestrictedActive crustal deformation and rotations in the southwestern Balkans from continuous GPS measurements(2020-04)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; The western limb of the Hellenic Arc defines the boundary of a large intracontinental active extensional domain covering the Aegean and the southwestern part of the Balkan peninsula. Along this boundary a transition from collision in the north to subduction in the south is associated with post-Miocene clockwise rotations of . We present a new GPS velocity field that, with new permanent station velocities in Albania, Bulgaria, Kosovo, Montenegro, and Northern Macedonia, provides insights into previously unresolved aspects on the large-scale dynamics of continental lithosphere and on the relation between long and short-term kinematics. In particular we address (1) the kinematic description of the collision/subduction transition, (2) the relation between long-term finite rotations with geodetically-measured instantaneous rotations, (3) the forces maintaining and resisting the deformation of the extensional domain and (4) the extent of its northern boundary. We use the analogy of rigid elongate inclusions in the velocity field to predict the senses and approximate rates of rotation of crustal blocks in the deforming continental region. Across the collision/subduction transition zone a large rotational pattern in the velocity field is found whose spatial pattern and sense of rotation is compatible with the observed paleomagnetic rotations through the occurrence of fault-bounded block rotations. Geodetic observations show that clockwise vertical axis rotation of the western limb of the Hellenic margin is active today, with distribution and rates that are essentially the same as that defined by the paleomagnetic data for the last 5 Ma. The maximum rates of the rotational component of the velocity field is found along the wide arrangement of fault-bounded blocks in central Greece that accomodate the NE-SW dextral shear transferred from the northern Aegan trough. The northern limit of the rotating margin defines a hinge (Scutari-Pec transverse zone) that has remained stationary throughout the Middle Miocene (relative to the upper plate of the collision/subduction system) with important implications for the distribution of strength of the western margin of the Hellenic Arc. The distribution and style of deformation along the western boundary of the extensional domain is controlled by the relation between gravitational forces, driving the flow of crustal material towards the low-lying adjacent regions sea floor, and heterogeneous resistive forces along the collision/subduction boundary.195 6 - PublicationOpen AccessInsights on continental collisional processes from GPS data: Dynamics of the peri-Adriatic belts(2015)
; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ;We present a new GPS velocity field covering the peri-Adriatic tectonically active belts and the entire Balkan Peninsula. From the velocities, we calculate consistent strain rate and interpolated velocity fields. Significant features of the crustal deformation include (1) the eastward motion of the northern part of the Eastern Alps together with part the Alpine foreland and Bohemian Massif toward the Pannonian Basin, (2) shortening across the Dinarides, (3) a clockwise rotation of the Albanides-Hellenides, and (4) a southward motion south of 44°N of the inner Balkan lithosphere between the rigid Apulia and Black Sea, toward the Aegean domain. Using this new velocity field, we derive the strain rate tensor to analyze the regional style of the deformation. Then, we devise a simple test based on the momentum balance equation, to investigate the role of horizontal gradients of gravitational potential energy in driving the deformation in the peri-Adriatic tectonically active mountain belts: the Eastern Alps, the Dinarides, the Albanides, and the Apennines. We show that the strain rate fields observed in the Apennines and Albanides are consistent with a fluid, with viscosity η ∼ 3×1021 Pa s, deforming in response to horizontal gradients of gravitational potential energy. Conversely, both the Dinarides and Eastern Alps are probably deforming in response to the North and North-East oriented motion of the Adria-Apulia indenter, respectively, and as a consequence of horizontal lithospheric heterogeneity.355 45 - PublicationOpen AccessThe Engineering Strong‐Motion Database: A Platform to Access Pan‐European Accelerometric Data(2016)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;This article describes the Engineering Strong-Motion Database (ESM), developed in the framework of the European project Network of European Research Infrastructures for Earthquake Risk Assessment and Mitigation (NERA, see Data and Resour- ces). ESM is specifically designed to provide end users only with quality-checked, uniformly processed strong-motion data and relevant parameters and has done so since 1969 in the Euro- Mediterranean region. The database was designed for a large variety of stakeholders (expert seismologists, earthquake engi- neers, students, and professionals) with a user-friendly and straightforward web interface. Users can access earthquake and station information and download waveforms of events with magnitude ≥ 4:0 (unprocessed and processed acceleration, velocity, and displacement, and acceleration and displacement response spectra at 5% damping). Specific tools are also available to users to process strong-motion data and select ground-motion suites for code- based seismic structural analyses.283 177