EGU2020-7728
https://doi.org/10.5194/egusphere-egu2020-7728
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Tomography image of double high-velocity heterogeneity beneath the Eastern Alps from the AlpArray data

Jaroslava Plomerová1, Helena Žlebčíková1, György Hetényi2, Luděk Vecsey1, Vladislav Babuška1, the AlpArray-EASI Working Group3, and the AlpArray Working Group3
Jaroslava Plomerová et al.
  • 1Institute of Geophysics, Czech Academy of Sciences, Prague, Czechia (jpl@ig.cas.cz)
  • 2Institute of Earth Sciences, University of Lausanne, Switzerland
  • 3http://www.alparray.ethz.ch/

Convergence between the European and African plates formed the Alps and the neighbouring mountain belts. We present results based on teleseismic body-wave data from the AlpArray-EASI complementary experiment (2014-2015, Hetényi et al., Tectonophysics 2018) and the AlpArray Seismic Network (Hetényi et al., Surv. Geophys. 2018). Tomography of seismic velocities in the upper mantle, as well as seismic anisotropy study along a ca. 200 km broad and 540 km long north-south transect (crossing the Bohemian Massif in the north, the East-Alpine root, and reaching the Adriatic Sea in the south), image the steeply northward dipping East-Alpine root, dominated by the Adriatic plate, steady southward thickening of the lithosphere beneath the Bohemian Massif and distinct regional variations of mantle lithosphere fabrics modelled in 3D. These characteristics imply complex, domain-like architecture of the collisional zone of the European/Adriatic plates beneath the Alps. Thanks to the close spacing of the AlpArray stations and high-quality data, the high-resolution tomography resolved for the first time two neighbouring high-velocity northward-dipping heterogeneities beneath the Eastern Alps, instead of one thick root of the lithosphere. The southern one, which we relate to the Adriatic plate, is more distinct, the northern one is less pronounced, it delaminates at ~100km depth and diminishes in direction toward the Central Alps. It may represent a remnant of an early phase subduction of the European plate with the switched polarity (relative to the polarity in the Western Alps), or a preceding phase of the Adriatic subduction.

How to cite: Plomerová, J., Žlebčíková, H., Hetényi, G., Vecsey, L., Babuška, V., Working Group, T. A.-E., and Working Group, T. A.: Tomography image of double high-velocity heterogeneity beneath the Eastern Alps from the AlpArray data, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7728, https://doi.org/10.5194/egusphere-egu2020-7728, 2020

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