Question

When scientists examine the gases ejected during a volcanic eruption, the majority of the gas is water vapor. How does the process of subduction provide a water source for volcanic gases?

Answer 1

Answer:

When an oceanic crust and a continental crust converge, the denser oceanic crust subducts under the continental crust. During this process, seawater is added to the volcano’s magma. Much of this water is heated and ejected during an eruption as water vapor.

Explanation:

Answer 2

Answer: Volcanic gases are gases given off by active (or, at times, by dormant) volcanoes. These include gases trapped in cavities (vesicles) in volcanic rocks, dissolved or dissociated gases in magma and lava, or gases emanating from lava, from volcanic craters or vents.