Question

Choose the correct statement(s) related to different aspects of volcanism.

• A. Andesites are the most common rock type associated with stratovolcanoes
• B. Explosiveness of volcanism depends on viscosity and fluid content of the magma
• C. Shield volcanoes represent one of the largest magmatic vent landforms
• D. Pillow lavas reflect sub-aerial volcanic eruptions

Hint:

Shield volcanoes form from low-viscosity basaltic lava, while stratovolcanoes form from intermediate lava, such as andesite. Explosive eruptions depend on magma's viscosity and gas content.

Answer 1

The Correct Option is A, B, C

Step 1: Check the andesite claim.
Stratovolcanoes are steep cones built mainly from andesite, a medium silica lava. So statement A is true.

Step 2: Check the explosiveness claim.
How violently a volcano erupts depends on how thick the magma is and how much gas it holds. Thick, gas rich magma traps gas and blows up. So statement B is true.

Step 3: Check the shield volcano claim.
Shield volcanoes are broad, gently sloped giants built from runny basalt, like Mauna Loa. They are among the largest volcanic landforms. So statement C is true.

Step 4: Check the pillow lava claim.
Pillow lavas form when lava erupts under water and chills fast into rounded lobes. They are not from eruptions in open air. So statement D is false.

Step 5: Final choice.
The correct statements are A, B and C.
\[ \boxed{\text{A, B, C}} \]