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
Dormant Commerce Clause Unless we can conclude on the whole record that "the total effect of the law as a safety measure in reducing accidents and casualties is so slight or problematical as not to outweigh the national interest in keeping interstate commerce free from interferences which seriously impede it" we must uphold the statute. There are two notable exceptions to the dormant Commerce Clause doctrine that can permit state laws or actions that otherwise violate the Dormant Commerce Clause to survive court challenges. The first exception occurs when Congress has legislated on the matter. See "Western & Southern Life Ins. v. State