My constant caveat - tides, especially diurnal tides, although weak, could affect earthquakes, and I (sporatically) continue to see wonder if we'll find such a relation more clearly than we have.

However, it is clear that the biggest earthquakes in the last century didn't noticeably tend to strike when the tidal stress oscillations were the largest, and neither did the last couple of decades of Bay Area and Pacific Northwest quakes. These studies Roger and I were involved in all involved hundreds to thousands of earthquakes, not just a handful at a time.

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