My guess is that earthquakes powerful enough to cause a head crash are powerful enough for widespread destruction anyway, but I’m no expert. I did some quick searches for hard drives damaged by earthquake, and the only results I got were scenarios where the hard drives or the whole rack got knocked over by the earthquake and hit the floor.
Magnetic hard drives are sensitive to vibration. You can shout at hard drives and measure the effects (video: https://www.youtube.com/watch?v=tDacjrSCeq4).
One of the worst-case scenarios is a head crash. A head crash will damage the media and may result in data loss. https://en.wikipedia.org/wiki/Head_crash
My guess is that earthquakes powerful enough to cause a head crash are powerful enough for widespread destruction anyway, but I’m no expert. I did some quick searches for hard drives damaged by earthquake, and the only results I got were scenarios where the hard drives or the whole rack got knocked over by the earthquake and hit the floor.