Rock can melt at a depth of about how many km below Earth's surface.?

Rock can melt at depths of approximately 30 to 50 kilometers (about 18 to 31 miles) below the Earth's surface. At these depths, the combination of high temperature and pressure can cause rocks to undergo partial melting, leading to the formation of magma. The exact depth can vary depending on the geothermal gradient and the composition of the rocks.