Final answer:
Decompression melting is the process of melting due to a decrease in pressure on solid rock. It commonly occurs in the Earth's mantle as hot rock rises towards the surface.
Step-by-step explanation:
Decompression melting occurs when there is a decrease in pressure on a solid rock, causing it to melt without an increase in temperature. This process is commonly observed in the Earth's mantle, where hot, solid rock rises towards the surface. As the rock moves upwards, the decrease in pressure causes it to undergo decompression melting and form magma. This magma can eventually reach the surface and erupt as volcanic lava.