This prophecy exists basically in two parts. The first comes from Jesus Himself who predicts that there will be a massive rise in deadly diseases, plagues, pestilences, and unexplained sicknesses and maladies in the last days. We're already seeing that right now. But then this event kicks into overdrive when the 4th seal is opened. It's as if Jesus takes an already raging fire and pours rocket fuel on it. You can somewhat picture the resulting aftermath that would cause. o_0;; Most biblical scholars view this as being two separate events. I simply see it as the same event in two stages. The first is a warning of what's to come through smaller, less impactful events, and the latter is the main event that rocks the world to its very core. As such, the first part is simply judgment, but the second is outright wrath, and since wrath can't fall on this world until the Church is taken away in the rapture, all we will see for now is just lots of smaller events; samples of what's to come once the restrictions are lifted and the seal judgments begin to fall.
(*Do you have a better description, or did you find an error? Please let me know.