This concept is invoked to explain how different topographic heights can exist at Earth's surface. Isostasy does not upset equilibrium but instead restores it (a negative feedback). It is generally accepted that Earth is a dynamic system that responds to loads in many different ways. However, isostasy provides an important 'view' of the processes that are happening in areas that are experiencing vertical movement. Certain areas (such as the Himalayas) are not in isostatic equilibrium, which has forced researchers to identify other reasons to explain their topographic heights. In the case of the Himalayas, which are still rising, it has been proposed that their elevation is being supported by the force of the impacting Indian Plate. The Basin and Range Province of the Western US is another example of a region not in isostatic equilibrium.