Complex sentence: The crater is not perfectly circular, but is about 6% broader in a northeast-southwest direction and the internal parts of the crater are also asymmetric is such a way as to imply that the impact was oblique from the southwest.
Split into simpler sentences: The crater is not perfectly circular, but is about 6% broader in a northeast-southwest direction. And the internal parts of the crater are asymmetric in such a way as to imply that the impact was oblique from the southwest.