No Reasonable Explanation
We were visiting my in-laws around Christmas and we were chatting in their den, having some drinks, and catching up. They had a Christmas tree in the corner of the den. Nobody was sitting near it. My husband and father-in-law were sitting in lounge chairs and I was sitting with my mother-in-law on the couch on the opposite side of the tree.
The two dogs were napping between us. We were all at least six feet away from the tree. All of a sudden, their Christmas tree begins to shake violently. It was as though someone had grabbed the trunk and was shaking the dust off of it. A few Christmas ornaments fell to the ground and then it stopped. It shook for a good 10 seconds.
The thing is, we were the only four in the house, the dogs were sleeping on the couch with us, the tree had been up for at least a week so no woodland creatures were hiding in it and nothing else in the house shook. No glass clinking, no other rumbling sounds, just the tree. We still checked the news to see if there was an earthquake.
We checked both websites and newspapers and there were no reports of an earthquake. We also live in an area where earthquakes are rare. So, I have no clue what shook the tree. We all saw it, and the dogs slept through it. They did not care a bit.