GEOLOGY

Detailed explanation-1: -Asthenosphere is the main source of magma that finds its way to the surface during volcanic eruptions.

Detailed explanation-2: -Magma originates in the lower part of the Earth’s crust and in the upper portion of the mantle. Most of the mantle and crust are solid, so the presence of magma is crucial to understanding the geology and morphology of the mantle.

Detailed explanation-3: -Deep inside Earth, between the molten iron core and the thin crust at the surface, there is a solid body of rock called the mantle. When rock from the mantle melts, moves to the surface through the crust, and releases pent-up gases, volcanoes erupt.

Detailed explanation-4: -Consequently, water is released and migrates upwards into hot overlying mantle. This water lowers the melting temperature, causing partial melting of the ultramafic mantle to produce mafic (basaltic) magma. This magma then migrates upwards and may reach Earth’s surface.