Apart from the three elevation zones already mentioned, it is possible on the basis of geologic structure, climatic conditions, and differences in geomorphologic development to divide China into three major topographic regions: the eastern, northwestern, and southwestern zones.
Catastrophic natural events, such as volcanic eruptions, earthquakes, and devastating storms, can have obvious consequences for the instability of geomorphologic patterns.
Regional research in physical geography is also well advanced, and in 1963 a geomorphologic committee for the Carpathians and the Balkans was established.
A mass of data on the environment, soils, flora, fauna, land use, settlement patterns, and artifactual history of the entire region has become available through geomorphologic, hydrologic, and archaeological surveys.
Later geomorphologic studies include those conducted by Italians, notably Ardito Desio and Giotto Dainelli.
Through such methods, especially when combined with geomorphologic techniques, it is possible to demonstrate that at no time in the past were all areas irrigated.
A number of ways of classifying depositional environments exist, but most modern schemes employ a geomorphologic approach.
In the geomorphologic history of the Great Alfold, a range of block-faulted mountains, coincident with the present plain, submerged into an inland sea (known as the Pannonian Sea) in the Pliocene Epoch (i.e., about 5.3 to 2.6 million years ago).
