East Coast Earthquake appeared to have only damaged the TOPS of structures. Hmmmm.....

I don't find it odd that the tops would be damaged. Hold a pencil on end (eraser side down) and sway it back and forth without moving from the spot where it touches the table. The top moves the farthest out of line and undergoes the most acceleration changes.

OP, as I understand the mechanics of the situation, the force on the building comes from the earthquake energy coupling into the building's foundation. That could certainly cause damage directly.

But in addition to this, the earthquake force will excite characteristic vibrational modes in the building's structure, causing the building to vibrate throughout, especially to higher areas that could resonate strongly and "swing and sway" as a result. That's what happened to the National Cathedral in my opinion. There was more swaying at the top of the spires than lower down, which is why the damage was near the top.

You bring up a great point. I live in Northern IL. On my local news Facebook page, a whole page discussion went on about people who felt the earthquake 950 miles away. People who were 3 floor or up in buildings reported feeling swaying. There were NO reports of people on the ground feeling it. People who didn't feel it said to those who did, Oh, you are crazy, you need meds. Even after I tried to explain to them not only was it possible, but it makes sense b/c of the bedrock under us, no one wanted to listen.

I wish I knew what it was! We also heard a loud thunder, which they said that happened around the time of the swaying. There was a thunderstorm in the area, so I am thinking it's with that.

oscillating resonance.

crack a whip with a small wrist snap - the tip travels a much longer arc than the handle in your hand.

the oscillations of the shaking magnify exponentially up building... it's why here on the west coast if you're on the TOP floor of a tall building during an earthquake you're in for a ride.


[link to www.youtube.com]

same principle as torque i think

Could be, or perhaps a Chinese space-based weapon firing from ABOVE.