ETH dump, apparently. it's diving down like crazee for the past few days. since feb 15 the price went down for about 50% and market cap down by $180M (35%).
How will dumping ETH help the bitcoin price? It is not like people are buying more bitcoin after dumping bitcoin, they are actually holding the bitcoins then.
actually when people dump altcoin their first choice is always btc or fiat. so sell ETH -> buy BTC/fiat. some people who will get no profit because they bought ETH just before it went down will look for other options, while the ones who believe they can secure profit in BTC will go with BTC.
simply look at the volume of ETH/BTC on some exchanges.
there are of course other possibilities. but this one is the most logical conclusion because the price started to climb when ETH went down.