Here are a few questions for this board's geology experts:

1. What do geologists mean by the term "tidal triggering" (of earthquakes)? When many people hear the word "tide," ocean tides come to mind. But I believe that geologists are also talking about the "Solid Earth Tide" and perhaps even air tides in the atmosphere.

2. Ocean tides and Solid Earth Tides both have crests and troughs which travel towards the west as the Earth rotates relative to the sun and to the moon. Are those crests and troughs for both types of tides at about the same longitudes? Or are there significant differences in those longitudes?

3. Do ocean tide and Solid Earth Tide crests and troughs usually run straight north and south. Or do they at times travel on a large angle relative to straight north and south?

Ocean Tide data generation program:
http://tbone.biol.sc.edu/tide/sitesel.html

Solid Earth Tide data generation program:
http://www.gik.uni-karlsruhe.de/~wenzel/etgtab30/