A volcanic eruption produces lava, ash and gases. ... Volcanoes cause limited erosion directly; the underside of a new lava flow scours topsoil or loosely consolidated sediments. Volcanic eruptions are the indirect causes of substantial erosion through the action of volcanic debris on the atmosphere, land and water.
Political is because In political science, a political system defines the process for making official government decisions. It is usually compared to the legal system, economic system, cultural system, and other social systems.