Tidal phase locking is weak, does not rise as injection pressure builds, and is the same before and after large events.
Earthquakes respond to tidal stress only when fault pore pressure is within about ten per cent of failure, so the appearance of tidal sensitivity is a precursor rather than a permanent background property.
Not supported
We took every M≥2.5 earthquake in the USGS ComCat catalogue for Oklahoma (2009–2024) and California–Nevada, and removed aftershocks within one day and 10 km of a larger event. For each origin time we computed the equilibrium solid-earth tide from the Moon and Sun, band-passed it to the diurnal and semidiurnal band, and read its phase from the analytic signal. A Rayleigh test then asks whether origin times cluster in tidal phase. We tested three things the claim requires: phase locking in 100-event blocks through the Oklahoma injection cycle; the same in California as a tectonic control; and phase concentration in the 90 days before versus after each M≥4.5 event.
The claim makes tidal sensitivity a state variable that tracks distance to failure. In the one place where pore pressure changed by a known amount over a decade — Oklahoma — the signal does not follow it, and it does not rise before rupture. What locking exists is a property of particular windows, not a precursor. The result is a null, and a useful one: a free catalogue-derived precursor would have been valuable, and this catalogue does not contain it.
We used the vertical body tide only. Ocean loading, fault geometry and the full stress tensor would change the phase for individual events, though not the absence of a time trend. Pore pressure is proxied by the injection era rather than measured, and catalogue completeness varies across the sequence. The California box includes part of Nevada.