DETERMINATION AND ASSESSMENT OF LANDSLIDE HAZARD INDEX IN THE HASHTJIN AREA (NORTHWESTERN REGION OF IRAN)
Abstract
We present a technique for hazard index assessment
that is used to prepare the landslide prediction map
of the Hashtjin area (northwestern region of Iran) at a 1:50000
scale. The proposed technique makes it possible to determine
the degree of landslide hazard and assess the landslide
risks. It is established that landslides occur most often on
slopes composed of alternating waterproof and water-bearing
rocks. The displacement of large masses of soils or rocks
on a slope is most often caused by wetting the soils by rain
water. As the soils are filled with water and become heavy and
more mobile, they slide over the slopes. Although the action
of gravity is the primary driving force for a landslide to occur,
there are other contributing factors affecting the original slope
stability, namely, an increase in the steepness of the slope
due to washing away the soil; the weakening of strength of
rocks due to weathering, precipitations and groundwater; the
influence of seismic shocks; construction and economic activity.
The volume of landslide damage depends on the reason
which gave rise to the landslide; in some cases it can affect
large areas. Landslide hazard analysis makes it possible to
establish the location of potential inclined slopes and to estimate
the volume of the landslide, its frequency and distance
traveled. To assess the landslide hazards, necessary data are
processed by a GIS. A GIS offers a superior method for landslide
analysis as it allows one to generate landslide maps and
maps of likely occurrences of future landslides.
that is used to prepare the landslide prediction map
of the Hashtjin area (northwestern region of Iran) at a 1:50000
scale. The proposed technique makes it possible to determine
the degree of landslide hazard and assess the landslide
risks. It is established that landslides occur most often on
slopes composed of alternating waterproof and water-bearing
rocks. The displacement of large masses of soils or rocks
on a slope is most often caused by wetting the soils by rain
water. As the soils are filled with water and become heavy and
more mobile, they slide over the slopes. Although the action
of gravity is the primary driving force for a landslide to occur,
there are other contributing factors affecting the original slope
stability, namely, an increase in the steepness of the slope
due to washing away the soil; the weakening of strength of
rocks due to weathering, precipitations and groundwater; the
influence of seismic shocks; construction and economic activity.
The volume of landslide damage depends on the reason
which gave rise to the landslide; in some cases it can affect
large areas. Landslide hazard analysis makes it possible to
establish the location of potential inclined slopes and to estimate
the volume of the landslide, its frequency and distance
traveled. To assess the landslide hazards, necessary data are
processed by a GIS. A GIS offers a superior method for landslide
analysis as it allows one to generate landslide maps and
maps of likely occurrences of future landslides.
References
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