"The title of this thread explains why this quake is a major event. Now, as I already mentioned above, the immediate question is, :
- why is this major event assigned a 3.9 mag ?"
Uh...could it be because it WAS a 3.9 magnitude quake? They don't pull magnitudes out of their hats, you know. It's based on instrumentation.
A 3.9 can do local damage.
I doubt you will still say that after reading the comments at the end of the linked page.