OK Ara...I reread Shan's post at the top of this thread...but not others he made before with some information on his method. Besides some problems in his geology ("lava at the core of the earth which moves the earth plates with
huge force and tend to stabilize its actual position."), it simply seems impossible for there to be a couple cm shift in the normal path of the shadow across a few feet (1 m). So, the method seems simple enough, it just does not seem that it can work. The question becomes, assuming the couple cm shifts he is measuring are real, what is causing them? I think it has to be some local effect...for example...is the object that is causing the shadow suspended? Could wind cause that object to move? Could wind cause the wall of Shan's house to flex?
Chris