Earthquakes in mountainous regions may be more damaging as they can create landslides and severely weaken the foundation of buildings.6.2 is not considered a relatively small earthquake. It's considered a strong earthquake. Hitting a higher populated area can cause a lot of damage. Not to say that the buildings couldn't have been built better but a similar quake hit northern California last year. Tons of buildings collapsed but few deaths due to sparse population.
Landslides from an older earthquake.