On 1/6/2016 10:58 AM, Eagle wrote:
Don Y formulated the question :
The idea of the *ground* moving is just fascinating to me! It's one
thing to be on a man-made structure and experience motion (Harvard
Bridge, Royal Gorge Bridge, tall buildings, etc.); yet another to be on
"solid ground" and feel it move!

It IS an interesting experience! I remember a 6.2 shaker in 1970 when the brand
new freeway overpass in Northern Los Angeles fell. We were in bed on the second
floor when it hit, and I watched our building rock back and forth, bang! bang!
and the street rolled like waves for a good 2 minutes. It was fun!

The Harvard Bridge (Cambridge-Boston, MA) sort of "floats". When you
walk on it, passing traffic causes the bridge to "bounce". So, you have
this competing rhythm that screws up your walking pace; instead of "step,
step, step" it's "step - boing - step - boing, boing - step". It can
be disturbing the first time you encounter it.

The "roadway" of the Royal Gorge Bridge is built of *planks* laid on
steel supports. So, when the (occasional, touristy) car drives by, the
planks flex and lift you up a bit. As they are only ~10-12 inches wide,
you can visibly watch the ripple in the roadway as the car advances
past you. At ~1000ft to the river below, you really wish they'd opted
to use something other than LUMBER!!

I'd like to be in an open field (away from buildings that might tumble)
to experience an earthquake. To be able to *think* about what is
happening and "gather data" (observations) to try to rationalize what
my body would be feeling. (having to worry about my personal safety
would sort of hamper that!)