New numerical and theoretical model to characterize the upper crustal structure of the moroccan atlas from wide-angle seismic reflection data

摘要

© 2015 Shagun Mudgil, Harika Nambula and B. Bharathi. The upper crust beneath the Moroccan Atlas has been modeled using the travel time of wide-angle arrivals from the SIMA (Seismic Imaging of the Moroccan Atlas) dataset. The detailed knowledge of the internal structure of this orogen allows understanding its uncommon characteristics, featuring high topography, moderate tectonic shortening and moderate crustal thickening. The -700 km long SIMA wide-angle reflection seismic profile has provided a high resolution geophysical data set to obtain a shallow P-wave velocity model along the transect. The seismic data processing has enabled us to accurately pick the first arrivals of the seismic records. Subsequently, the development of a numerical code to mathematically model the hodochrones defined by the first arrivals, has provided us the P-wave velocity structure of the crust down to 10 km. The resulting model shows a detailed image of the Atlas upper crust and reveals several relevant features that help to understand the structure of the orogen and its composition.