Asymmetric valley

An asymmetric valley is a valley that has steeper slopes on one side. Asymetric valleys are azonal landforms. In high altitudes south-facing slopes are usually steeper than north-facing slopes. Large incised rivers crossing strike-slip faults can form asymmetrical valleys as one bank of the river might be continuously being renewed while the other bank drifts away from the river. Smaller river does not develop asymmetrical valleys as the whole river is offset or bent by the fault, rather than the river modifying the moving tectonic block. Examples of these kind of asymmetrical valleys are can be found at the crossing of the Yellow River with the Zhongwei-Tongxin fault.