MohoroviČiĆ discontinuity (Moho)

Abstract

The Mohorovičić seismic discontinuity, known today as the Moho, was discovered in 1909 by Andrija Mohorovičić. It is defined by a jump in seismic velocities from 5.6 to ~7.8 km/s. It represents the boundary between the more felsic crust and the mafic mantle. Combining seismic, gravity, and other data to map the Moho has led to global compilations (CRUST1.0 and GEMMA2012C) that have achieved impressive resolution and coverage. The petrologic and seismic Moho do not always coincide because of complications due to eclogitisation and serpentinization. Modern seismic techniques have revealed richness in structure including double and inverted Mohos at subduction zones (Bostock, 2013) and great complexity in continental regions (Cook et al., 2010; Carbonell et al., 2013). It is now clear that the Mohorovičić discontinuity is a dynamic feature. Ongoing efforts include detecting and understanding other changes in physical properties across it, such as electrical conductivity, scale changes in heterogeneities across it, and viscosity.