It's probably not because of that. Before they use to talk about HAARP; I heard HAARP closed down many years before.
It's most probably due to the tectonic plates. As has been said big earthquake happen about every 80 years or so in the Himalyan region. (They talk a lot about earth quakes in the regions like California and Japan as well. )
I remember when I was going to college in Kathmandu, I saw an engineering fair organized by civil engineering students where they talked about the importance of building pillar system house as oppposed to just walls and ceiling, and putting iron rods in such way so that concete slab is stronger. They have been voicing concerns, but their voices mostly fell on deaf ears as most house owners, builders do whatever they like, or resort to substandard construction to save some money. To be honest I think that most Nepalese probably thought they won't experience a big earthquake in their lifetime, even though it was probably just a generation ago that Nepal experienced a severe earthquake. Perhaps this tragedy will bring something positive in Nepal in terms of standards and following rules.