| Popis: |
First images of structure and dynamics of the Alpine orogeny came mostly from recordings of permanent observatories. Though density of permanent observatories has increased substantially since mid of the 20th century, yet it was not enough for detailed structural studies of the lithosphere-asthenosphere system in the complex Alpine-Mediterranean mountain belts. The tomographic images have changed especially during the last three decades, when several both small- and large-scale passive seismic experiments recorded huge amount of high-quality data at dense arrays, composed from both permanent and hundreds of temporarily installed stations. Thus the former monotonous eastward striking bend of the Alpine orogeny split into separated subductions with opposite polarity, one in the Western Alps and one in the Eastern Alps (Babuška et al., Tectonophysics 1990), later confirmed in more detailed tomography by Lippitsch et al. (2003), which included data from the TRANSALP experiment (TRANSALP Working Group, EOS 2001), the first research transect oriented on orogenic processes in the Eastern Alps. Data recorded during international AlpArray experiment, series of its complementary projects (e.g., EASI, SWATH-D, PACASE) as well as several other previous small-scale experiments (e.g., ALPASS, BOHEMA, CIFALPS, CPB) allowed to unravel details of the Alpine structure and to search geodynamic models of the Alpine subductions. However, new questions arise with the new more precise images of the Alps. Following questions belong among them: 1) what is the origin of the E. Alpine subduction (Adriatic or European, or both); 2) if the E. Alpine slab is attached or detached, or, at which depth it resides; 3) how different methods, particularly crustal models incorporated into the body-wave tomography, disturb the real visualization of the E. Alpine slab. In this contribution we image the E. Alpine slab, evaluate effects of the crustal models on perturbations in the upper 100 km of the mantle and aim at answering the basic questions on the subduction beneath the Eastern Alps. |
