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"Flying debris" occur when the earthquake acceleration exceeds the acceleration due to gravity. That effect was first noticed in the 1973 San Fernando earthquake, at nodal points. It has been observed since then at other points throughout the world.

Those points are relatively rare, and those <1.0 accelerations are equally rare. A co-worker of mine who lived in the Sherman Oaks (San Fernando Valley) area during the 1994 Northridge earthquake, reported that her countertop microwave was propelled across the kitchen into the refrigerator door, leaving a large indentation.

"Flying debris" can certainly be a source of injury, but toppling debris and broken glass are more likely culprits.

I interviewed an emergency room physician who was on duty in Southern California the morning of the Northridge earthquake (which occurred about 4:30 AM local time). Through wide areas of southern California, the electricity and lights went out as the 20-25 shaking continued. I asked the physician what type of injury from the earthquake was most commonly presented in the emergency room. The answer might surprise you. It wasn't crushing injuries, broken bones, or heart attacks. It was lacerations to feet, caused by people walking on broken glass in the dark!

If anyone wants to start a home earthquake kit, phase one is to make sure you have a sturdy pair of shoes near your bed and a flashlight with fresh batteries. There is roughly a 33% chance you are going to be in bed when a large earthquake strike.