Question

question 9 (1 point) volcanic arcs and island arcs are both created by what? a subduction at a transform boundary b convergence of two continental plates resulting in uplift c lightning striking a mountain, creating magma pockets d collision and subduction of an oceanic plate with another plate, melting crust into magma that escapes

Explanation:

Volcanic arcs and island arcs are formed due to the subduction of an oceanic plate beneath another plate (either oceanic or continental). When an oceanic plate is subducted, it melts at depth, creating magma. This magma rises and forms volcanic activity, leading to the creation of volcanic arcs (if the subduction is ocean - continent) or island arcs (if the subduction is ocean - ocean).

• Option a: Subduction does not occur at transform boundaries. Transform boundaries are characterized by lateral sliding of plates.
• Option b: Convergence of two continental plates results in mountain - building (orogeny) due to uplift as continental plates are less dense and do not subduct easily.
• Option c: Lightning striking a mountain has no geological connection to the formation of volcanic or island arcs.
• Option d: When an oceanic plate collides and is subducted (either under another oceanic plate or a continental plate), the subducted plate melts, and the magma escapes to form volcanic and island arcs.

Answer:

d. Collision and subduction of an oceanic plate with another plate, melting crust into magma that escapes.