Keeping things in perspective, what is behind the volatility? Value??
keeping things in perspective, average returns on SPX 500 (which is most of the stock market value) has averaged 6-7% over many decades. From the 2008-2009 bottom market has advanced 215% in 7 years. That is 4 times faster than average. While economy has grown less than 3% per year.
So this market is way overvalued. All it takes is a hiccup somewhere for market to tumble. Right now it is China slowing down. To get back to historical average valuations, this market needs to drop another 25%. Overvalued market are prone to higher volatility.