At the beginning of what could be another volatile week, let's review volatility the S&P 500. The top chart features an overlay of the index and the CBOE Volatility Index (VIX). When you click on it, you'll link to a series of charts that review the S&P 500 and VIX over two timeframes 1990-present and 2007-present. I've also included identical versions with the VIX inverted to facilitate comparison with the underlying equity index. The VIX is nicely explained by Investopedia:

VIX: The ticker symbol for the Chicago Board Options Exchange (CBOE) Volatility Index, which shows the market's expectation of 30-day volatility. It is constructed using the implied volatilities of a wide range of S&P 500 index options. This volatility is meant to be forward looking and is calculated from both calls and puts. The VIX is a widely used measure of market risk and is often referred to as the "investor fear gauge".... VIX values greater than 30 are generally associated with a large amount of volatility as a result of investor fear or uncertainty, while values below 20 generally correspond to less stressful, even complacent, times in the markets.

The second chart was furnished by Serge Perreault, our regular weekend analyst, who makes the following comments:

The VIX appears to be traveling sideways between the support of 30 discussed by Chris Kimble in one of his previous charts [here] and the resistance of about 45. Looking at the attached chart, I wonder if it will "relax" as it did from December 2008 (leading to the rally from March 2009) or break out again and lead to another correction? Notice too how ROC3 led the index, ROC 13 and RSI4.

• ROC (Price Rate of Change)
• RSI (Relative Strength Index)