I discussed this in an old post and my most recent one:
https://steemit.com/cryptocurrency/@thecryptofiend/the-rise-of-ethereum-classic-a-black-swan-moment

https://steemit.com/cryptocurrency/@thecryptofiend/ether-wars-ethereum-classic-price-and-volume-reach-ath

I think this may be an orchestrated move by ethereum whales who are anti chain censorship and the HF. Plus ETC is more profitable to mine.