What is a typical volcanic hazard shown by shield volcanoes?

What is a typical volcanic hazard shown by shield volcanoes?

• A. Tephra
• B. Lava flows
• C. Pyroclastic flows
• D. Lahars

Answer: (B)

Shield volcanoes erupt with low-viscosity basaltic magma, so their eruptions are mostly effusive rather than explosive. That runny lava pours out to build broad, gently sloping slopes and can travel great distances from the vent. The most common and characteristic hazard is these lava flows themselves, which can destroy anything in their path as they advance downslope. Tephra and pyroclastic flows come from more explosive eruptions with higher-viscosity magma, which shield volcanoes typically do not produce as often. Lahars require a specific combination of ash, water, and eruptive activity and are not the defining hazard of shield volcanoes. So, the best answer is lava flows.

Shield volcanoes erupt with low-viscosity basaltic magma, so their eruptions are mostly effusive rather than explosive. That runny lava pours out to build broad, gently sloping slopes and can travel great distances from the vent. The most common and characteristic hazard is these lava flows themselves, which can destroy anything in their path as they advance downslope.

Tephra and pyroclastic flows come from more explosive eruptions with higher-viscosity magma, which shield volcanoes typically do not produce as often. Lahars require a specific combination of ash, water, and eruptive activity and are not the defining hazard of shield volcanoes. So, the best answer is lava flows.