Yellowstone National Park in Wyoming is home to a super volcano.
Naples has one of the highest volcanic risks in the world. Italy has a public warning system for this reason which sends direct information to the people living in the region about major emergencies or disasters. These alerts send messages to cell phones to alert people of upcoming eruptions. There are monitoring devices in place at the active volcano sites which keep track of vibrations or movements underground which scientists can use to predict eruptions. If there is a threat, the warning system has four alert levels - green, yellow, orange, and red, to indicate how severe or great the threat of an eruption is.
