Upper-mantle structure beneath the southern Bohemian Massif and its surroundings imaged by high-resolution tomography

• Published in: Geophysical journal international Vol. 194; no. 2; pp. 1203 - 1215
• Main Authors: Karousova, H., Plomerova, J., Babuska, V.
• Format: Journal Article
• Language: English
• Published: Oxford University Press 01.08.2013
• Subjects: Body waves; Europe; Seismic tomography
• ISSN: 0956-540X; 1365-246X
• DOI: 10.1093/gji/ggt159

We present a new velocity-perturbation model of the upper mantle down to 300 km retrieved by teleseismic tomography beneath the southern part of the Bohemian Massif (BM) and its surroundings. Though the upper mantle beneath the BM appears as extensive low-velocity heterogeneity in large-scale tomography studies of Europe, our regional study based on data from passive experiment BOHEMA III and the northern part of the ALPASS array reveals also velocity features at scales of ∼40 km. The most distinct low-velocity perturbations concentrate along the Eger Rift down to ∼200 km, while velocities at greater depths beneath this rift show high-velocity perturbations relative to the overall low-velocity character of the BM mantle. Two significant high-velocity heterogeneities dominate the tomography images. The most distinct and extensive one, located south of the BM, we associate with the eastern Alpine root. The second high-velocity heterogeneity can be traced in horizontal slices down to 215 km beneath the central part of the BM. These positive perturbations seem to shift from the southwestern part of the massif at shallower depths to the northeastern part of the BM at greater depths. The heterogeneity can reflect the lithosphere thickening resulting from the collision of the BM with the Brunovistulian (BV) microplate from the east and the following underthrusting of the BV beneath the Moldanubian part of the BM.