Recently ETH got huge price increase. Is there any specific reason for that much of Increase ? 
I agree, the etherium began to grow rapidly and this growth can continue until February 2018. I believe that such a rapid growth is due to the active involvement of users through many ICOs.
Why only until February? I think Ethereum has great prospects for development. After switching to PoS, the price should go up.
It's not only limited in a single month but it will increase every month if the year. Investors of Ethereum are increasing that's why it rises rapidly but not as abrupt as Bitcoin.
Ethereum deserves to be pumped and so as Altcoins.