Yohji Kudou

The fracking seems plausible enough to me. What's hard to understand is why they don't just come out and say that's what it is. There's theories that it could be from underground digging but the problem with that is dirt and rock don't just vanish into nothingness - if they're digging out these huge areas underground, there have to be piles and piles of dirt and rock building up somewhere nearby - or at least trucks carrying all that away. No reports of any of that.