More of ETH's price is increasing due to the price of Bitcoin. Since BTC is increasing price it's dollar value is seeing a spike too. Similarly ETH's dollar value is seeing the spike because of BTC's value. Although there is a significant increase in ETH's BTC value too. That's why Ethereum has increased a lot over the past few days. It will be best to hold the whatever ETH we have. Don't buy more ETH since BTC is on the rise and might bleed ETH.