the compression of the atmosphere would be similar to many millions of atomic bombs going off, so actually the entire planet would be enveloped in something similar to an atomic shockwave, where the cars move 100ds of meters sideways in the wind, without even thinking about the ground movement happening at the same time. The ground movement would occur prior to the wind effects, moving very fast and very far compared to an ordinary earthquake.
The air itself would become alot less clear because of all the thermal and compression effects happening within it, water would vaporise be compressed while the wind would be going at 1000kph, so you wouldnt see very much.
There is a documentary on nova with scientists discussing the effect of a neutron star invading the solar system, it's totally false because the iron of the earth would compress against the crust like a huge hypervolcano, and pop out of the breach in the crust and fly into space, long before stones would start to fly around.
It depends on the velocity of impact, typically at meteoric velocities.
The effect would be similar to an large earthquake of which the main shockwave would be transported directly through the mantle rather than around the crust. The effect would be different depending on the angle from the percussion.
The power of the shockwaves would be enough to create waves of force lifting the crust in heights in between 10 meters and 1000 kilometer, depending on what rebound of the wave you first catch, cars would literally be flung very far into the air a few seconds after the initial schockwave occured, and the intensity of the earthquake would increase until the entire surface of the earth was wabbling and cracking by in waves at least 100 kilometers tall.
The precise model of the surface and the earth's crust's interaction with the viscous and compressed inner materials of the earth would be a function of the earth crust's thickness and the size of the shock waves traversing the mantle, disassembling the crust in the first moments while the observer was alive. 208