I think only a press release has been published at this time by the researchers mentioning the underground structure. I haven’t read it yet so I’ll be looking for it to see if the statement is accurate. But here is the narrative that is being circulated online for more context:

nostr:note1a83pxgvkmtandawe5v9wkvvg7jljmep6uyxtwc6gsxd7kdvsqwdsd6sl62