text:  is about a once-a-year occurrence. This is about once a year. The tides only give you an idea as to when. For any real earthquake prediction, you need to have when, where, how big, and you should give probability. So we lick the when, in many cases, with the tides. So as to the where and how big, you rely upon the local effects. We know what the tides are going to be years ahead of time.