The routes by which a natural (not man-made) slope has reached its present state may be split into two main categories:-

• Those which are made up of a series of long-term processes, many of which are still active,
• Those which are made up of processes which act for a short duration, so much fewer active processses carry on at present.

This second category of slope takes much more investigation to discern the original cause of slope formation, and an understanding of these processes is essential for a successful engineering investigation, and to know how to deal with problems of instability which may arise.

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