This study aims to analyze the change of land use, vulnerability of landslide, and soil erosion focusing on increase of cropland area and resultant decrease of forest land, using remote sensing and GIS techniques for selected study areas in North Kore ...
This study aims to analyze the change of land use, vulnerability of landslide, and soil erosion focusing on increase of cropland area and resultant decrease of forest land, using remote sensing and GIS techniques for selected study areas in North Korea.
The results of the research on land use change of cropland and forest are following:
1. The forest area has decrease during 13 years from 1990 to 2002, due to development of urbanized settlement, formation of waste land by human impact, and increase of natural hazards such as flooding and landslide in western Pyeonganbulkdo including Sakju, Daewan, Guseong, and Euju.
2. Cropland areas has spreaded toward steep knickpoint of hillslopes with formation of patch-like waste land, and geomorphic hazard such as slope erosion and sedimentation by rill and gully in lower reach zone of Duman River during last 10 years.
3. The average elevation of cropland has changed from 381m of 1993 year to 412m of 2002 year with increase of cropland slope from 10° to 13° in Manpo and Gangye area. Also, the number of patch by fragmentation has rapidly increased from 394 to 1.241 in some duration together with increase of shape index and fractal dimension.
4. Soil erosion by cropland development are comparatively higher in elevation of 300-500m, showing increase of the volume from 57 ton of 1987 year to 85 ton of 2001 year in Hoeryeong area. Area of over 200 ton volume with higher vulnerability of landslide has increase remarkably from 28.6km2 of 1987 to 48.8km2 of 2001.
The results of regional studies about slope unstabilization and vulnerability of soil erosion are following:
1. In Hameung study zone, knickpoint belt of hillslope are higher vulnerability for concentration of rainfall.
2. In Wonsan zone, footslope areas of Secokwangsa, Anbyeon, and Muncheon are more dangerous by high dense landuse.
3. In Gilju zone, higher vulnerable areas of slope unstabilization are in along Gilju-Myeongcheon faultline valley with impact of faulting action of cropland development.
4. In Cheongjin zone, North mountain footslope area shows higher vulnerability of landslide during Jangma and rainy seasons.
5. In Pyeongyang zone, metropolitan-neighbored mountains slopes of northeast, east, and southeast aspects have higher vulnerability of unstabilization. In coastal zone, especially Eunyul area are higher vulnerability of unstabilization. Resultantly, braided channels have well development by surface soil erosion in high-middle reach.
6. In Yeongbyeon zone, urbanized settlement area has increased toward footslope belt and along deeper valley.
7. In Sineuju zone, higher vulnerability areas of slope unstabilization, due to surface erosion, are Euju, Sackju and Guseong with mountains landforms.
8. In Jungangjin zone, the area of unstabilized slope include backslope of river terrace and valleyside slope.
9. In Hyesan, unstabled areas are located along sideslopes of faultline valley and dissection valley of lava plateau, in which soil processes are less activated especially in weathered layers.
10. In Musan zone, open iron pit are the center of unstabilization areas concentrated in northeast slope area.
11. In Jongseong and Heoryeong zone, surface erosion areas are partially located in valleyside slopes of Duman River, due to geomorphic characteristics such as less sementated Tertiary layers.
Finally, the results of the research may help to understand natural landscapes and environmental problems of North Korea to restore natural ecosystem, and to reconstruct geography education of North Korea and unification education.