All interesting @cryptotrader, many thanks for sharing. I think you have to look at these as corroborating indicators rather than triggers as such, at least for me. Take the Vix for example, it essentially spikes when there is a panic and not before, although you may see a creeping up as nervousness takes hold. After a period where the Vix was uncommonly low (around 10) in 2017, there have been 3 spikes in 2018 (Jan,Mar and Oct). All spiked after the drop was already well under way. In the case of Jan and Oct (the more significant drops) the VIX spiked up from low bases circa 10 +/- to over 20 (29 and nearly 25) in a matter of days. What is interesting now perhaps is that it has not yet dropped back down to the lower end. Perhaps it will do so on any rally in stocks and if it does get back down then I would take that as a preparation for another drop in stocks because it is a contrarian indicator of complacency.
Check out my post on "US Stock Market - S&P500", which is also related to this topic and puts my above comments into perspective. I am basically laying out a position that the end is already nigh, it is just a matter of whether the top of the market is already in or has one more leg up to go. I am discounting the notion that there is "still a bit more to go" and economists consensus that 2020 will be when the next recession happens as no one has offered any answer to how far and where it will end, because of course they can't!