Earthquakes affect humans on a couple different levels.
Being raised in Los Angeles, and being subjected to numerous earthquakes of small to medium size over the years (up to M7.1), I have seen first hand the effects.
In physical terms, the houses, buildings, roads, utilities, and supply “lines” are all affected by earthquakes - a building may collapse and kill or injure people and their pets. They might have lack of water supplies from pipes being broken, or natural gas pipelines rupture causing fires, and power could be our (or all at the same time).
Access to the homes of their parents or adult children or friends may be cut off as a critical road overpass has collapsed and now takes two major roads out of service. Especially where people cannot venture outside their homes, other people need to get to them.
Earthquakes are unpredictable- and aftershocks even more so. I remember that my first thought on feeling an earthquake was “is this the earthquake or just a foreshock to a bigger one?” Just when you think the quake and its effects are “all accounted for” then aftershocks can make whatever hadn't fallen down to fall down, making the situation worse.
Everything around you could be rubble, and there are serious issues with getting help and supplies not only for yourself but also to your families. The necessities of life consume all your time.
Now comes the mental / psychological effects of living with earthquakes. I have met people who are unable to restore balance in their daily lives, because EVERYTIME the Earth twitches (and it twitches a lot) they panic. Sometimes it happens to people who have recently moved into the LA area; sometimes it's with people who are long time residents that just reached their saturation point and snapped, and they have to get out.
Earthquakes take a very real toll on humans.
I remember that the first casualty in one of the quakes in LA was a motorcycle policeman rushing in the early dark to respond to the emergency and drove across a freeway overpass that was no longer there.