Actually, there was far more surface or terrestrial destruction across the land southward. This upheaval actually changed this region of the western hemisphere into a huge continent. Prior to this time the Land southward was described as a long rectangular territory surrounded by a sea east, a sea west, a sea south and a sea north.1
It appears the Andes Mountains were not as formidable as they are today. But it does indicate in Alma 22:32 that there was an isthmus or narrow neck of land which connected the land southward to the land northward as it does at the present time. The Book of Mormon would suggest that within three hours the sea south was replaced by a huge extension of land which today we call lower Chile and Argentina. On the other hand the sea east was pushed aside to make way for Brazil, Paraguay, Uruguay and Bolivia. Scientists have a wonderful time debating this alleged phenomena -- as they should -- but we are simply describing what the Book of Mormon indicates must have happened.