ABSTRACT
In contrast to the super eruption of Ilopango, most explosive volcanic eruptions have only localized near-field impacts on their environments caused from the volcanic ashfalls. They can be destructive to nearby flora, fauna, and humans where deposits are greater than a few centimeters, especially more than ten centimeters. Most eruptions are not violent enough to blast tephra above the tropopause and thus have intensive effects close to the source, and diminish with distance. Although not recognized as due to volcanism, historians for decades have known that a multiyear dramatic and disastrous climatic crisis affected many areas of the world, its beginning precisely dated to the year 536 ce. Although much of the occupied world at that time was not literate, there are some important exceptions. The Bubonic Plague, also known as the Justinian Plague, occurred in the years shortly following 536 CE, and Keys argues that the cold period allowed it to happen.
