Interesting, Graham.  I've been aboard during several minor earthquakes and never felt them: the water has apparently dampened the shock, so to speak.  I guess it depends very much on the depth and magnitude.  This dreadful earthquake in Italy is quite low magnitude, but very shallow. 

Poor people - I hope they are in warm shelters before winter comes, and I hope that they aren't still fighting for their insurance claims to be settled 6 years later, like people are in NZ.

I was motoring into Double Bay East, just north of the Whitsunday Islands, on 20/08/16, on the first leg of a 200 mile passage to Magnetic Island, when the region was hit by a 5.8 magnitude earthquake, with a centre about 60 km away.  The boat began vibrating severely and, not knowing what was happening, I thought I'd broken an engine mount or something.  I quickly put the engine into neutral and the vibration stopped.  Rushing below, I inspected the engine room but could find nothing amiss.  I then went on deck and peered over the side, wondering if something had fouled the prop. Nothing again.  Arion was drifting towards the rocks, so I either had to hoist sail, anchor, or put the engine back in gear.  I cautiously put it in gear and motored into the bay.  Twice more there were brief periods of vibration and I hastily dropped the anchor further out than I intended.  I then thoroughly examined everything and could find no cause.  I went to bed that night in an unhappy frame of mind, wondering if I was developing a serious engine problem.  It was only the next morning, when I got back into phone range, that I heard about the quake.  Luckily there was little damage ashore and no tsunami.  Italy seems to have fared worse, poor souls.