There have been 20 VIX spikes of 20% or more in one day since 1990. Today makes 21, with the VIX currently up 21% on the day at 13.52.
Looking at that group of 20 VIX spikes, you can see the footprint of 9/11, the dot com bubble bursting, the Asian financial crisis and similar difficult periods. It is worth pointing out that in 17 of those 20 instances, the VIX was lower 3 days later, 5 days later and 10 days later (interestingly enough, it was a different grouping of VIX spikes that defied the trend in each time period.)
If history is any guide, the VIX should subside about 10% over the course of the next three days and another 2% or so by a week from now. This is the mean reversion tendency of the VIX at work.
While the SPX is ‘only’ down 1.5% at the moment, it is also worth recalling previous research posted here that when the SPX drops 3%, the VIX’s mean reversion tendency over the next five trading days paints a telling picture.