A series of normal faults and associated grabens exists on top of the Oxaya anticline. These faults have the same NNW-SSE orientation as the long axis of the anticline. The Oxaya anticline developed from the Miocene onwards as a direct or indirect response to east-west shortening of the South American plate in the context of the Andean orogeny.[1] Three models have been proposed to explain the anticline:[1]