NNW-SSE orientation. It is assumed that this characteristic resulted from the formation of the East Sea, which was heavily influenced by the geological structure of the continent. The peninsu- la also has relatively steep mountainous areas and diverse landform features, even though it does not have high elevations. Another characteristic of Korean topography is that the boundaries between mountainous areas and sedimentary atlands are rather unclear. This phenomenon can be explained by slow tectonic movement and relatively small sedimentary atlands across the peninsula. 

When considering the topography of the Kore- an Peninsula, the Sikhote-Alin mountain range, Southern China south of the Yangtze River, and Japan, the average elevation in descending order is as follows: Sikhote-Alin (507.0 m), the Korean Peninsula (448.5 m), Japan (390.9 m), and South- ern China (312.8 m). However, the average slopes of each area show a different order; Korea (5.7 ̊) has the highest average slope, followed by Japan (5.4 ̊), Sikhote-Alin (5.2 ̊), and Southern China (5.0 ̊). Landform diversity has yet another order, with Southern China (3.0) showing the highest value, followed by Japan (2.9), Korea (2.8), and