The blast created this fault, the last thing the test team were expecting. This is from the cavern generated by the nuke pushing under the surrounding desert and lifting it up. This feature, in this case due south of the site, is clearly visible on satellite images.
A few miles south west is another test hole. The first thing we found was the concrete warning markers. They all have the same placard which proclaims that the site is contaminated with petrochemicals and digging, drilling and removal of material is illegal. People report that the DoD occasionally has armed plain clothes guards at the site, but not the twice we have been there.
In this case it was never used, so there's a new looking concrete cap on a fifty year old and half mile deep hole. We stood on the cap, I'm glad it was in good repair.
eta: here's the video of the Faultless test. This sends chills down my spine and I am amazed I could stand on the site. They are currently drilling in the area to check for radiation leakage.