At 20:30 UTC on 16. August 2012 there was an magnitude 3.7 earthquake in Netherlands according to EMSC web site.
The earthquake in Netherlands at 20:30 UTC (22:30 local time). This earthquake was mostly felt in the area where it did happen. This picture is released under Creative Commons licence. Please see CC page for more details.
Some have already been speculating this earthquake might be due to gas extraction in this area. That might be. But there is also an chance that might have just been intraplate earthquake that sometimes happens. There might be other factors at work here that I do not know about. But I am not well into local geology of this area at current time.
It is hard to know if any aftershocks are going to take place. But I find them unlikely at current moment. But that might change without warning.
Blog post has been updated. The earthquake size and location has been revised.