The range of physical phenomena associated with volcanic hazardsVolcanic eruptions cause a wide range of hazards. This report will describe the different ranges of hazards associated with volcanic activity and discuss possible ways to avoid these hazards. A volcanic eruption can force people from their homes, damage water sources, destroy homes and farms, restrict movement and kill. Pyroclastic flow is a flow of volcanic rock and the most devastating effect of an explosive eruption. A pyroclastic eruption is one in which the vast majority of activity involves fountains or explosions. Nothing about a volcano is as hot and moves with as much power and speed as a pyroclastic flow. A pyroclastic flow begins with rocks and gases thrown up to 20 miles into the air in a mushroom cloud. Later, the column collapses and hot rocks and ash roll down the mountain. The rocks have the effect of running water that chokes everything in its path. The larger rocks are carried down the volcano while the smaller rocks rotate and act like a conveyor belt beneath them. It was a pyroclastic flow that destroyed Pompeii and killed thousands in 79 AD. Pyroclastic flows have nothing to do with the slow, predictable movement of lava. Molten rock crawls to the surface but very rarely takes lives as it is easily overwhelmed. Lava flows have a devastating effect on houses and other structures, as they can destroy them very easily. Heavy ash falls from the volcano can make breathing difficult and flatten homes. Ashes are particularly more dangerous if they are wet. Volcanic ash is material ejected by a volcano in the form of particles and measuring less than 2 mm in diameter. Ash can damage crops or force abandonment of an area. Earthquakes can be associated with volcanic activity, but they are usually small and shallow. Volcanic earthquakes are almost always caused by the movement of magma. When a volcano begins to show unrest, the earthquakes tend to be deep. As the magma batch moves toward the