I believe the fact that seismic events can trigger other seismic events along the same fault system is well known. What is still up for debate is how soon, how

I believe the fact that seismic events can trigger other seismic events along the same fault system is well known. What is still up for debate is how soon, how far away, and how large. I've heard it said that the only way you can tell if an earthquake is a fore-shock or the main event is to wait. For example, I've always loved this visualization of the seismic events leading up to the major Japanese earthquake of 2011: https://www.youtube.com/watch?v=NSBjEvPH2j4 https://www.youtube.com/watch?v=NSBjEvPH2j4 . See if you can identify the main quake when it happens. I bet you're wrong!