It's not a big quake here. But some of these people live in fairly primitive housing.
I am a native of So. Cal so I am familiar with earthquakes. :-)
I have also lived in earthquake prone areas, in which relatively minor earthquakes can cause major structural damage.
There was around a 4.2 earthquake in one place I lived, about 40 mi. from the epicenter, which was enough to swing the lights and wake us up early in the morning. No big deal. Well, it was a big deal where the earthquake was centered. The little town lost many many buildings, and a couple of thousand people were suddenly on the streets, their apartments crumbled, or cracked beyond habitability.
The earthquake in Bam probably wouldn't have ruffled too many feathers if it happened in LA.