In fa-taḍammanathā, fa is a connective, taḍammanat is a feminine perfect verb and hā is its object pronoun. The following place name Fardah is understood as the verb’s subject.
The construction makes the land appear active, as if it contains Nawār within its boundaries. That is poetic personification, not a literal action. Meanwhile, bi-mashāriq al-jabalayn is a prepositional phrase specifying the location.