block mountains | formation of block mountain | fault block mauntains

brief information about formation of block mountains also known as fault-block mauntains

[Itsme-gzbp]

Why middle block will go downside, why you had uplifted the eraser, if you uplift the eraser then the middle part will go downside because there is nothing beneath middle part, but in the case of earth, there is asthenosphere down there, so why will the middle block go downside????