First Nephi 19:10-14
The rending of the rocks and groanings of the earth didn't just happen to the people in the Book of Mormon. As verse 11 says, when Jesus was crucified, he visited all the house of Israel - some with his voice if they were righteous, some with natural disasters if they weren't. This verse adds "many kings", specifically of the isles of the sea, who also witness the calamities that happen when Christ dies. I fully expect archeology to unearth one of these records, and read word for word that the God of nature suffers. It would be some obscure island nation that made an account of this great destruction. Perhaps many accounts in many different nations will be discovered. Notice how the kings knew from the Spirit, exactly what was the cause of the earth's distress.