https://www.dmr.nd.gov/ndgs/landslides/24k/vlyc_w_l.pdf
Overall, approximately three percent (958 acres) of the land area
within the quadrangle has been affected by landslides.

ili 'affected by landslide activity'
http://www.springerlink.com/content/k808epj000w3x1f6/
Korshrostam is one of the areas most susceptible to landslides in Iran with more than 13% of its surface being affected by landslide activity. The effects include damage or disturbance to villages, farmlands and roads as well as the exacerbation of erosion of the land surface and consequently an increase in the rate of sedimentation in the water flowing into the reservoir of the Manjil dam.



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Note added at 1 hr (2009-06-30 22:06:40 GMT)
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Izvinjavam se, propustila sam da uključim i 'odron' u odgovor - to bi bio 'rockfall' u ovom kontekstu:
http://en.wikipedia.org/wiki/Rockfall
Rockfall refers to quantities of rock falling freely from a cliff face. A rockfall is a fragment of rock (a block) detached by sliding, toppling, or falling, that falls along a vertical or sub-vertical cliff, proceeds down slope by bouncing and flying along ballistic trajectories or by rolling on talus or debris slopes,” (Varnes, 1978). Alternatively, a "rockfall is the natural downward motion of a detached block or series of blocks with a small volume involving free falling, bouncing, rolling, and sliding".