Which statement best describes the hazards associated with stratovolcanoes?

• A. Primarily lava flows
• B. Ash clouds, pyroclastic flows, lahars
• C. Only steam emissions
• D. Only surface deformation

Answer: (B)

Stratovolcanoes are built from viscous, silica-rich magma that tends to trap gases, leading to explosive eruptions rather than steady lava flows. The most dangerous and characteristic hazards are ash clouds that can rise high into the atmosphere and drift with winds, causing aviation disruption and respiratory and grounding concerns for nearby populations; pyroclastic flows, which are incredibly hot, fast-moving mixtures of ash, gas, and volcanic material that race down slopes and destroy anything in their path; and lahars, volcanic mudflows formed when ash mixes with water from rain or melting snow, capable of flowing long distances down river valleys and burying infrastructure. These hazards reflect the explosive style and eruption dynamics of stratovolcanoes. While lava flows can occur, they are not the dominant risk compared with explosive ash clouds, pyroclastic flows, and lahars, and steam emissions or surface deformation are not by themselves the main hazards.