Volcano of classifying magmatic volcanoes is by their frequency of eruption, with those that erupt regularly called active, those that have erupted in historical times but are now quiet called dormant or inactive, and those that have not erupted in historical times called extinct. However, these popular classifications—extinct in particular—are practically meaningless to scientists. They use classifications which refer to a particular volcano's formative and eruptive processes and resulting shapes. There is no consensus among volcanologists on how to define an "active" volcano. The lifespan of a volcano can vary from months to several million years, making such a distinction sometimes
Active shooter and fails to grasp the nature of the threat involved. For civilians, when necessity or obligation calls, the tactical mandate is to attack the attacker—a strategy that has proved successful across a range of incidents from Norina Bentzel (William Michael Stankewicz) in Pennsylvania and Bill Badger in Arizona (2011 Tucson shooting) to David Benke in Colorado. The active shooter incidents do not always meet the classification of a mass murder. Mass murders result when three or more individuals are killed. The definition of an active shooter does not require that victims are killed, only that they are injured or wounded