International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004 
  
5.2 Landslides 
Denuded hill slopes (Figs. 5, 6) correlate to areas of disturbed, 
possibly burned, vegetation seen in Fig. 3. LANDSAT TM 
resolution (30 m) precludes detection of shallow landslides in 
NDMIDIR images, however, numerous fresh shallow landslides 
are detected in the higher resolution IKONOS FCC image (Fig. 6). 
Landlides are identified on the basis of tone (indicating exposed 
surfaces) and feature shape. Collectively, these results 
demonstrate correlation of landslides to denuded surfaces. This 
correlation is significant to establishing a causal and temporal 
relationship between episodes of vegetation disturbance and 
landsliding. 
  
  
  
Figure 4. FCC using IKONOS imagery, Pat Sin Leng Range. 
Yellow Insert - see Figure 5. Blue insert — see Figure 6. 
  
  
Figure 5. FCC highlighting eroded surfaces and disturbed 
vegetation (pale colours) south of the Pat Sin Leng escarpment. 
The Pat Sin Leng trail that traverses the escarpment crosses the _ 
image from top left to centre right. 
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6. CONCLUSIONS 
Using remotely sensed data we are able to depict disturbed 
vegetation, denuded hill slopes, and shallow landslides in natural 
terrain. Our preliminary work indicates positive correlation 
between these factors. This is an important finding in support of 
the use of remotely sensed data to predict landslide-prone terrain 
in Hong Kong. This work compliments that of the GEO, CED 
natural terrain landslide mapping programme by providing 
synoptic environmental information (particularly anthropogenic 
effects) for large areas of natural terrain, and a means to 
investigate specific causative factors. 
We have restricted our investigation here to LANDSAT TM and 
IKONOS data, but there would appear to be great potential in 
using this and other remotely sensed data, such as airborne 
radiometrics (Cranfield, 2003, pers. comm.) to map specific 
ground conditions including the identification of areas of 
alteration and deep weathering that may be additional pre- 
disposing factors for landsliding. In the longer-term, such work 
will serve to inform relevant sectors of local government of the 
potential risks associated with major land development projects. 
  
Figure 6. FCC highlighting shallow landslide scars (e.g. arrowed) 
in a denuded area, northern Pat Sin Leng Range. Note the absence 
of landslides within the red areas depicting healthy vegetation 
cover. 
REFERENCES 
Bannari, A., Morin, D., Bonn, F., Huete, A. R., 1995. A review of 
vegetation indices. Remote Sensing Reviews, 13, pp. 95-120. 
Barbosa, P. M., Gregoire, J. M., Pereira, J. M. C., 1999. An 
algorithm for extracting burned areas from time series of AVHRR 
GAC data applied at a. continental scale. Remote Sensing 
Environment, 69, pp. 253-263. 
Cannon S.H., 1997. Evaluation of the potential for debris and 
hyperconcentrated flows in Capulin Canyon as a result of the 1996 
Dome fire, Bandekier National Park Monument, New Mexico. 
USGS Open Field Report, pp. 97-136. 
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