the cause of bitcoin volatility, as it is affected by the news that scares the bitcoin users that bitcoin is likely to be governed by the government, the security vulnerability makes investors react, making the bitcoin unstable. Tax imposition on bitcoin also affects the volatility of its price.
Cryptomarket is very volatile, and the news makes it more volatile. People react on that negatively especially for those new in cryptoworld. There is no specific cause of bitcoin's volatility but I think its more on the emotion of every traders and the manipulation of a great whale.