Assessment Effect Water-Ice Equilibrium Line for Landslid
Aim: Often in studying the landslide, some factors are evaluated within the framework of various models such as type of
lands, atmospheric rainfalls, gradient change, earthquake, volcano eruption, changes in underground water, and human
reasons. Even though the above factors can have essential share in creating this phenomenon, but the necessary and
sufficient condition for creation of such phenomena is the historical background for the bed of lands that have experienced
particular formative processes, and this subject has been neglected by many individuals.
Place and Duration of Study :This area has been located at the southern part of Isfahan province. It is limited from west to
Lordegan in Charmahal Bakhtiari, from east to Fars province, from south to Kohgiluyeh and and Boyrahmad.
Methodology: In order to approve this hypothesis and historical manifestation of this area, using Wright Model and IDW
Model in Software of Arc GIS, water and ice equilibrium line and permanent snow line was determined in Quaternary cold
phase and then following results were obtained with adaptation of this map and the occurrence site of this landslide.
Results: There is no significant relation between occurrence of this landslide and regional landslides with two superior
geological factors, type of lands and slope that have been introduced as the most important factor in occurrence of
landslides.The location of this landslide is exactly between the line of permanent snow and equilibrium line for water-ice at
Semirom area that existence of glacial deposits proves this claim.
Conclusion: The average for the percent of occurred landslides in these 3 height ranges in the area indicate that about 90 %
of the landslides occurred in the limit between permanent snow line and water-ice equilibrium line, 9 % upper the
permanent snow line and 1 % within the limit lower than water-ice equilibrium line. Thus the highest occurrence of
landslides (%90 ) occurred in the limit between permanent snow line and water-ice equilibrium line.
Key words- landslide, water-ice equilibrium line, permanent snow line, Hardang, changing climate.