one hazard is gases: carbon monoxide, carbon dioxide, hydrogen sulfide and sulfur dioxide
carbon dioxide gas killes the most people out of all the gases
pyrochlastic flow is a fast moving current of hot gas and volcanic matter that flows along the ground away from the volcano and can reach average speeds of 100 km/h
lava flow can reacg up to 30 km/h but it usually isnt a major danger
ash fallout is when ash falls on an area this can cause respiratory problems and damages crops and damages buildings.
the main cause of death during eruptions are pyroclastic flows