What type of eruption typically produces pyroclastic flows?

A Plinian eruption is characterized by its explosive nature, which is why it typically produces pyroclastic flows. During this type of eruption, a large volume of magma is rapidly expelled from the volcano, creating a powerful upward explosive column that can reach significant heights. As the eruption column collapses, it can generate pyroclastic flows—high-density mixtures of hot gas, ash, and volcanic rock that flow down the slopes of the volcano at high speeds. These flows are incredibly dangerous due to their speed and temperature, making Plinian eruptions particularly hazardous.

The other types of eruptions listed do not commonly produce pyroclastic flows. Effusive eruptions, for example, are characterized by the relatively gentle flow of lava. Hawaiian eruptions are known for their relatively calm lava fountains and flows, lacking the explosive characteristics seen in Plinian eruptions. Phreatomagmatic eruptions occur when water interacts with magma, creating steam explosions, but they typically do not generate the large pyroclastic flows associated with Plinian eruptions. Therefore, when considering the relationship between eruption types and pyroclastic flows, Plinian eruptions stand out as the correct choice.