The term pyroclastic best describes fragmented materials ejected by volcanoes. Pyroclastic materials, also known as tephra, are fragments of volcanic rock and lava that are ejected during a volcanic eruption. These materials can vary in size from fine ash particles to large boulders and can travel long distances depending on the force of the eruption. They can also form pyroclastic flows, which are rapidly moving currents of hot gas and rock fragments that flow down the side of a volcano.