It does not reproduce, It must be due to minecarts then, I do have a quite a few in the area. They are technically motionless, but the game acts like they are moving. I guess this just leads to me asking if there could ever be toggle to eliminate that particular sound, I've longed for that in the past. Well, thanks for the quick reply, and I guess this can be considered resolved.
This will also happen in the Nether, standing on the edge of a Lava Lake is quite treacherous. It's like sliding downhill.