The geodynamic meaning of the deep earthquakes: First clues for a global perspective for fold-belts?

Abstract

Earthquakes are not uniformly distributed either along mountain belts and arcs or in depth. The zones in which the deeper earthquakes originate are shown, and their regional and global context is examined. The characteristic inhomogeneous pattern is inspected in the Italian region as well on Mediterranean and global scale. A possible reinterpretation of global tectonics is proposed with non-collisional orogenic processes – involving global expansion, rifting, isostasy, surfaceward flow of deep material, gravitational spreading, and phase changes. The associated model of evolution of an orogen does not resort to large scale subduction. The model – with the right modifications for the local different situations – could apply to the evolution of the Italian and world orogens.