Insights on continental collisional processes from GPS data: Dynamics of the peri‐Adriatic belts

Abstract

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.

Constraints from GPS measurements on the dynamics of deformation in Anatolia and the Aegean

“…Our analysis supports the conclusions of previous studies [e.g., Hatzfeld et al , ; Le Pichon , ; Le Pichon and Angelier , ; Martinod et al , ; McKenzie , ; Métois et al , ; Özeren and Holt , ] that tectonic activity in Anatolia and the Aegean is explained by the balance between internal gradients of GPE within the continental lithosphere of the region and the deviatoric stresses required to deform the lithosphere. Calculations in which deformation is forced solely by boundary tractions fit the observations significantly more poorly (RMS misfit ∼7.5 mm/yr, Figure d).…”

A Combined Velocity Field of the Mediterranean Region

“…The NE-ward to N-ward motion of the Adriatic domain and the W-ward to SW-ward motions of the Anatolian and Aegean plates highlight the kinematics of the most important microplates of the Mediterranean area (McKenzie, 1970). Plates and microplates relative motions are accommodated across the major plate boundary zones, well mapped by the release of seismicity.…”

“…Although some of the station velocities have been already published elsewhere, and the overall surface kinematics is well known and discussed in several recent papers (e.g. Nocquet, 2012;Serpelloni et al, 2013;Kreemer et al, 2014;Métois et al, 2015, Palano et al, 2015, here the velocity field is represented for the first time at the Eurasian plate scale with homogeneous standards, best available spatial resolution and special care for reference frame stability. Moreover the velocity field is obtained by re-processing the whole data set with different approaches and combining the velocity fields with the aim of building on a regular basis a high level GPS product for the scientific community.…”

Active Seismotectonic Deformation in Front of the Dolomites Indenter, Eastern Alps

“…With regard to the Eurasian reference frame of Métois et al (2015), the northern foreland and the northwestern margin of the Eastern Alps (region Eu' in Figure 9b) move toward NE/ENE. Compared to region EA, the north component is slightly lower, but there is no visible difference in the east directed velocity (Métois et al, 2015). This is also supported by a recent GNSS velocity solution of Austrian stations by Madzak et al (2017) and the data set of Sánchez et al (2018).…”