I actually think "unearthed" as in "discovered" is the more reasonable read - along with someone thinking they're clever in making a pun. When history is "unearthed" with radar, we generally assume some folks took a big expensive machine aimed it at the ground and walked away with a strong indication that something exists down there - when it comes to delicate items (like, for instance a decaying longboat that exists in the earth merely as concentrations of plant fiber in a suspicious shape) and especially when it comes to human remains (that people are often very reluctant to move due for cultural reasons) that's especially the case.