I haven't been following all the aftershocks, but they are not uncommon especially after a large quake. The quake is generally large because there has been a long time since the last one, and a lot of stress has been built up. The large jolt relieved a lot of the stress, but there could be a lot more that end up as the aftershocks.

I'm from California and anything less than a 6 is barely mentioned. We expect quakes here, and have sufficient resources and regulations to require buildings be fabricated to withstand these relatively easily. In poorer parts of the world (or somewhere people don't expect them to occur) quakes we'd barely notice here can still be quite devastating.