It is hard to tell by the picture.
Did the metal studs at the base fail or did the rotational forces pull the concrete foundation right out of the ground?
These were all GE wind turbines. Most likely the steel was not meant to endure the stress put on the material.
Most likely the installation contractor did not use the proper materials. Less likely that the GE engineer did not design it properly.
Way too many in use to call it a design problem. Surely construction or material failt.