It's probably blasting related to prepping for the eventual revival of an underground test platform.

I don't know all the logistics, but they probably don't detonate them directly under the base, and subterranean drilling might be less evident from satellite than top side wells.

Its just an earthquake. Nevada has tons of earth quakes, the primary first quake was a 4.2 magnitude, felt in vegas, and was 4km deep. Some of the after shocks were 7km deep. It also wasn't actually on area 51, just near by. This is just clickbait.