Enormous subsistance craters are what I had in mind when I wrote “enormous crater”.

They’re not enormous relative to the length of LAN cables.

...if the test happens deep enough to contain the explosion. But even an initially contained explosion may produce a crater later when the pressure in the created cavity drops and the cavity collapses.

I don't know how you'd describe the image you linked to except a 'huge hole in the surface.'

To me, it’s just a depression (something shallow a computer cannot fall into), whereas the comment above made it sound like a pit (something deep it can fall into).