Very well said. The earth is ALWAYS active seismically. I have been fascinated by EQs (and geology) since I was a (nerdy) teen. One thing that I had read recently is that gas monitoring stations in YS had detected (I think back in February) high levels of helium gas. This peaked my amateur curiosity in terms of increased seismic activity (the 4.8) but also the anecdotal occurrences (EQ “lights” are they gas generated in the period before a quake?) Again, I’m an amateur who reads about this.
Now Chile. Other than Japan’s usual swarms prior to the 9.2 (I think it was a 6.1 in the days that was originally considered “the” quake...and then noted as a foreshock) I cannot recall a “swarm” that (Chile has been having moderate quakes for weeks) that were truly foreshocks before a “big” one. Last I checked, there was a 6.2 aftershock a few hrs ago.
Geology has been an interest of mine since I was a teen as well. I lived and later worked many years at a mine and it’s geology still fascinates me. I read texts and articles for fun.