The rally had already began two months before the Cyprus news hit the waves...Cyprus just happened to be in the news at the time Bitcoin was gaining media attention. No doubt Cyprus played a part in the bubble, but it was only one of many factors.

The main reason for the bubble, I believe, was simply herd instinct and a fear of missing out on something that could change their lives forever if they didn't buy immediately. Just like in the 2011 bubble, many bought simply because the longer they delay the less bitcoins they will be able to buy. Higher prices lead to others panic buying which leads to even higher prices etc. The amount of media attention also was a huge factor which fueled the bubble as new people outside of the community were brought into the market.

My 2 cents.