The parallel verse to this description is found in Mosiah 27:11. In the commentary on that verse we noted the cultural importance of the voice of thunder and the shaking earth (see that verse for the more complete analysis). In this retelling those elements continue to be present. They were sufficiently etched as a part of the experience that Alma includes them in this retelling, even though they clearly have no further connection to paganism in his mind. Nevertheless, they are significant, they had high meaning for him at the time, and they are therefore included in the retelling.