Why can heating beneath the lithosphere cause the ground surface to rise?

Heating beneath the lithosphere causes the ground surface to rise primarily through the process of thermal expansion.123

Like most materials, rocks expand when they are heated. When a broad area of the lithosphere is warmed—often due to the upwelling of hot material from the underlying asthenosphere—the uppermost mantle undergoes thermal expansion. This increase in volume and temperature causes the overlying crustal surface to experience [uplift].132

This mechanism is a key factor in the formation of many plateaus, such as the Ethiopian Plateau and the Massif Central. Because this process typically affects broad regions, the resulting uplifted landform often retains a relatively flat surface, distinguishing it from mountain ranges formed by crustal shortening. In some instances, this heating is associated with hot spots, where mantle plumes provide the heat necessary to both uplift the surface and potentially trigger volcanism.1435