That is no aftershock.
I was in a 7.5 in Mexico City many years ago. My date and I were standing in the middle of the street holding each other so we wouldn’t be knocked down. The telephone poles and wires were lashing back and forth, but there was no other sound. Eerie, but plenty of motion, like a fast moving NY subway ride. When I got home, I was told the living room chandelier had been swaying back and forth touching the ceiling on one side and then hitting it on the other. The guy living upstairs was tossed out of bed. If this was a 7.5, I can imagine what a 7.8 might be like.