The movement of material due to differences in density is called?

This movement is called convection. It can be found in liquids, gasses and rheids - solids that can also experience movement ( on a big time scale), such as the earth mantle. One of the types of convection is diffusion: net movement of gasses from higher to lower concentration areas.

Answer: the philippines has suffered from an inexhaustible number of deadly typhoons, earthquakes, volcano eruptions and other natural disasters. this is due to its location along the ring of fire, or typhoon belt – a large pacific ocean region where many of earth's volcanic eruptions and earthquakes occur.