The Slab Puzzle of the Alpine‐Mediterranean Region: Insights from a new, High‐Resolution, Shear‐Wave Velocity Model of the Upper Mantle

Mediterranean tectonics since the Lower Cretaceous has been characterized by a multi‐phase subduction and collision history with temporally and spatially‐variable, small‐scale plate configurations. A new shear‐wave velocity model of the Mediterranean upper mantle (MeRE2020), constrained by a very large set of over 200,000 broadband (8‐350 s), inter‐station, Rayleigh‐wave, phase‐velocity curves, illuminates the complex structure and fragmentation of the subducting slabs. Phase‐velocity maps computed using these measurements were inverted for depth‐dependent, shear‐wave velocities using a stochastic particle‐swarm‐optimization algorithm (PSO). The resulting three‐dimensional (3‐D) model makes possible an inventory of slab segments across the Mediterranean. Fourteen slab segments of 200‐800 km length along‐strike are identified. We distinguish three categories of subducted slabs: attached slabs reaching down to the bottom of the model; shallow slabs of shorter length in down‐dip direction, terminating shallower than 300 km depth; and detached slab segments. The location of slab segments are consistent with and validated by the intermediate‐depth seismicity, where it is present. The new high‐resolution tomography demonstrates the intricate relationships between slab fragmentation and the evolution of the relatively small and highly curved subduction zones and collisional orogens characteristic of the Mediterranean realm

The effect of magnetic field and thermal relaxation on 2-D problem of generalized thermoelastic diffusion

The generalized magneto-thermoelasticity is developed. The formulation is done under two theories: the generalized thermoelasticity coupled theory and Lord – Shulman theory with one relaxation time. The normal mode analysis is used to obtain the expres- sions for temperature, displacement components, the thermal stresses distributions and concentration of diffusion. The variations of the considered variables are represented graphically. A comparison is made with the results predicted by two theories in presence and absence of the magnetic field.Розвинуто узагальнену теорію магнітотермопружності. Сформульовано задачу в рамках двох підходів: теорії узагальненої зв’язаної термопружності та теорії Лорда – Шульмана з одним часом релаксації. Використано аналіз нормальної моди для отримання виразів для температури, компонентів зміщень, розподілу температурних напружень та концентрації дифузії. Зміну вказаних вище змінних представлено графічно. Порівняно результати в рамках обох теорій за умови наявності та відсутності магнітного поля