Fig. 11

P–T path, H₂O production, system volume change, and frequency of earthquakes in the crust. a Pressure–temperature (P–T) paths of the subducting oceanic crust for six subduction zone segments plotted on a diagram of maximum H₂O contents (Abers et al. 2013). P–T paths for the upper slab surface and slab Moho are shown as colored solid and dot dashed lines, respectively. Shading shows maximum H₂O contents in wt% for a hydrated metabasalt of MORB bulk composition (Hacker, 2008). Major dehydration reactions are indicated by A (lawsonite breakdown), B (zoisite breakdown), and C (amphibole breakdown). b–d Evolution of pore fluid pressure and H₂O content for cold and warm slabs (Abers et al. 2013). Hokkaido is indicated by blue lines as a representative cold slab and Kii by red lines as a representative warm slab. b Accumulated dehydration-derived H₂O content in wt% as dehydration reactions progress. c Rate of H₂O production, with Kii scaled by a factor of 10 relative to Hokkaido. d Total system (solid + H₂O) volume. Shaded in light blue and yellow denote depth intervals of major dehydration for Hokkaido and Kii, respectively. A, B, and C denote specific reactions shown in Fig. 11a. e Frequency of upper-plane earthquakes beneath central Hokkaido (Fig. 7d) as a function of depth (Kita et al. 2010)