Interesting.

Also, here are some refs you might be interested in:

Shirley, J., (1988). Lunar and Solar periodicities of large earthquakes: Southern California and the Alaska Aleutian Islands seismic region., Geophysi-cal Journal, Vol. 92., pp. 403 – 420.

Shlien, S., (1972). Earthquake – tide correlation., Geophys. J. R. Astr. Soc., Vol. 28, pp. 27 – 34.

Sounau, M., Sounau, A., Gagnepain, J., (1982). Modeling and detecting interaction between earth tides and earthquakes with application to an aftershock sequence in the Pyrenees., Bull. Seism. Soc. Am., Vol. 72, pp. 165 – 180.