Personally, I think the catalyst for the next correction in the stock market may come directly from the bond market.
The logic is this: if the bond yield (US10) were to return 1.40% why should I take on more risk by investing in the stock market with a dividend yield of just over 1.40%? As an investor, I would prefer to sell equities and buy some bonds.
Surely the FED will intervene with control of the yield curve in order to avoid a sharp downward acceleration.