Science Olympiad Dynamic Planet Practice Test

What is the typical slope range of stratovolcanoes?

1. 5-10°

2. 10-20°

3. 30-35°

4. 45-55°

The correct answer is: 30-35°

Stratovolcanoes, also known as composite volcanoes, typically have steep slopes due to their formation process, which involves the accumulation of volcanic materials such as lava flows, ash, and other volcanic debris. The conical shape of stratovolcanoes results from the eruption of relatively viscous lava, which does not flow far from the vent before solidifying, creating the characteristic steep incline. The slope range of 30-35° accurately reflects the angle typically observed in stratovolcanoes. This steepness is essential for their stability as it allows for the effective drainage of volcanic materials. The angle of repose for volcanic materials contributes to this slope, as the steep nature helps to prevent the collapse of the structure. Other volcanic types, such as shield volcanoes, typically have much gentler slopes due to their low-viscosity, fluid lava that spreads over greater distances.