' Subduction zone initiation (SZI) 'is the initiation of new, independent subduction zone in the presence of ongoing ocean-plate tectonics. More specifically, it is the onset of downward plate motion forming a new slab, which later evolves into a self-sustaining subduction zone. - Crameri et al. (submitted)
As distinguished from:
' Subduction initiation (SI) 'is the initiation of subduction (i.e., the sinking of oceanic plates into the mantle) in the absence of pre-existing subduction zones anywhere else on the planet.
While SZI describes the initiation of a feature (i.e., a subduction zone), SI describes the initiation of a process (i.e., subduction). As such, SZI and SI are describing two strongly different aspects of the ocean-plate tectonics, and must therefore be clearly distinguished from each other.
Figure from SZIdatabase.org: Subduction zone initiation (SZI) events. Some of the SZI events that occurred during the last 120 million years, and are included in the SZI database version 1.0, are indicated in terms of the present-day geographic locations of corresponding geologic evidence on an interrupted Mollweide projection of the Earth’s oceanic plates.