Comment on “Spatial changes in inclusion band spacing as an indicator of temporal changes in slow slip and tremor recurrence intervals” by Nishiyama et al.

Abstract

Abstract A recent paper by Nishiyama et al. (Earth, Planets, and Space 73:126) examined syntectonic quartz veins to constrain temporal variations in the recurrence intervals between slow slip and tremor events. The authors claim that by examining the liquid-volume fraction of syntectonic fluid inclusions in the veins, that they can accurately reconstruct pore-fluid pressures (and variations therein) that were operative during faulting at ~ 15 km depth in an exhumed subduction melange. From these observations, the authors infer that large (from lithostatic to hydrostatic) decreases in pore-fluid pressure occurred during faulting, and that these variations drove increases in supersaturation and rapid quartz precipitation over time scales consistent with the repeat times of seismologically observed slow slip and tremor events. Here, I show that Nishiyama et al.’s analysis neglects reasonable uncertainties in pore-fluid pressure reconstruction. When those uncertainties are included, the Nishiyama et al.’s results become ambiguous as to whether any variation in pore-fluid pressure during vein formation occurred at all, negating the validity of many of the subsequent conclusions. Graphical Abstract

Keywords

• Quartz
• Fluid inclusions
• Pore-fluid pressure
• Slow slip and tremor
• Low-frequency earthquakes
• Slickenfibers