Four great changes have happened since the formation of Loess Plateau and the fifth change will happen. The first change happened 2.50Ma ago

which is the change from laterite plateau to Loess Plateau

and the motive power is climate. The second change happened 1.60Ma ago. After this change

rivers advented

the change represents the change of new tectonic movement in Loess Plateau

the motive pewer is tectonic uplifting. The third change happened 15ka ago

and is affluent change of the Yellow River from running into lake to running into sea and the change of loess material from the internal transportation in Loess Plateau to the external one

the motive power is running water action. The fourth change happened 0.4ka ago

and is change from natural erosion to nonnatural acelerated one in the area

the motive power is mankind activity. The fifth change will happen in 100 years

which is the opposite change to the fourth one

the motive power is mankind activity

too.