Joint inversion for three-dimensional S velocity mantle structure along the Tethyan margin

초록

We construct a new three-dimensional S velocity model and Moho map by jointly inverting regional S and Rayleigh waveform fits, teleseismic S and SKS arrival times, fundamental mode Rayleigh wave group velocities, and independent Moho depth estimates for the region that extends from the mid-Atlantic ridge through northern Africa, southern Europe, and western Asia. The joint inversion benefits from both better resolution and wider data coverage than when using only individual data sets. Resolution tests confirm that the joint inversion yields good resolution ranging from the Moho to a depth of 1400 km. The complementary and overlapping nature of the different data sets' resolving power has reduced disparities in resolving power that exist for individual data sets, for example between resolving power for crustal and lower-mantle structure. This increases the utility of the new tomographic model for explaining and predicting a variety of observations and dynamics. The new model derived from the joint inversion assembles a large number of mantle structures known from a wide variety of previous studies into one model and in some cases reconciles different local studies that previously seemed contradictory. Finally, the model shows that shallow low-velocity anomalies beneath the Pannonian basin and the Iranian plateau are connected to similar anomalies in the transition zone, the latter possibly related to a deep dehydration process in the subducted lithosphere of the Neo-Tethys Ocean. The model shows the Hellenic slab penetrating the lower mantle, the Calabrian slab extending flatly in the transition zone, and discontinuous slabs beneath the Apennines and the Zagros belt.

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