Nothing will happen, its a different blockchain.
However, if Bitcoin price tanks it will for sure tank most of other cryptocurrencies too. This is why I recommend hedging against smartcoins that have a fixed value like SBD (1 dollar worth of steem) and BitUSD (one dollar worth of BTS).
Thanks for your answer. I know It's a different blockchain but the 2nd part u answered was my actual question. Thnx