مجله زمین شناسی مهندسی
سال یکم شماره 2 (تابستان 1382)

This study is an attempt to examine the Landslide potentials and landslide hazard zonation in Nojian Area. Nojian is located 30 km away in the south- east of Khoramabad, Lorestan province. In order to zonate the hazard of mass movement, first the natural maps including geology, slope, slope direction, landuse, regional-fault maps, the intensity of the earthquake, etc. were prepared. In the second stage this data set was digitalized. Then by drawing on field work, arial photo and digital data from satelite image, landslide – inventory map including falls and sliding were mapped on the base map of the study area. By incorporating natural maps with the landslide inventory map, the extent of sliding in different parameters was obtained. However, through the statistical method (area density) for each parameter like lithology, slope, slope direction, distance from fault, landuse, intensity of the rain, intensity of the earthquake, etc. the numerical value for each parameter was obtainted by matching and zonation landslide map was obtained. Finallay the resaults of the study shows that 81% of the region marked as high and very high hazard.

Zagros active fold-thrust belt lies on the northern margin of the Arabian continental crust it is a young fold-thrust mountain belt currently shortening, thickening and uplifting as a result of the collision of the Arabian and Iranian plates. Rethickening of crust during collisional orogenies could have been carried out by reversal of fault motion along the Mesozoic normal faults (Jackson 1980, Jackson and Fitch 1981, Berberian and king 1981, Jackson etal. 1981) This study constitutes contribution towards an estimation Rate of uplifting along the High Zagros Fault and fault patterns in the southern margin of High Zagros fold-thrust belt. The High Zagros deep-seated fault is located between High Zagros thrust belt and Zagros Simply Folded belt in the southern margin of the High Zagros belt. (Berberian, 1995). The Farsoon – Baghe Hiran –Goushki fault is a part of High Zaros Fault (H.Z.F) system and is located northeast of Lordegan city in Chaharmahal State.In this region on the basis of field geology a geological map (scale: 1: 50/000) is prepared. For the recognation of fault pattern, enechelon faults of H.Z.F. and estimation rate of uplifting along the H.Z.F three structural sections have been drawn. Correlation between geological structures, fault patterns in High Zagros Fault system ‘stratigraphic profiles’ enechelon. faults of H.Z.F and paleogeographic data give us an insight to many conclusions.There are many footwall-vergent shortcut thrust, hanging wall by pass thrust and hanging wall vergent back thrust developed with High Zagros fault. Footwall shortcut thrusts, hanging wall by pass thrust and backthrusts are common features of Inversion tectonic Settings. In this region, the fault pattern and stratigraphic curves indicate inversion tectonic in pre-existing extensional normal faults. -The minimum throw (uplifting) of a fault depends on the thickness of formations that is omitted along the fault and with respect to stratigraphic units thickness and geological cross sections, the minimum rate of uplifting along the H.Z.F. is about 2.05 0.1 mm/year

Because of transportation of the sedimentary materials from the surface of continents,the continental environments have a significance importance among the other river environments. The quantitative study of these environments is done on the basis of their driange basins. This study is also done on the basis of the same aspect, with a special attention to the influences of the sub-basin on the accumulation of the heavy minerals. The proposed basin is the NW part of Dez basin that is located between two different geological zones, called Sanandaj–sirjan and Zagros crush zone.These geological zones are seperated by Boroudjerd- Dorood plane.The strahler grading order was used for ranking. Due to our knowledge, third – order sub- basins were selected as concentred places of heavy minerals for further studies. The main basin of the proposed area was a six –order type, that is a relatively high degree. Four drinage anomalys were seen in this area, that one of them was affected by the lithology characters of area and other were affected by the faults. The results show that faults have significant rules on the formation of third- order sub- basin. The proposed area has a suitable maturation, due to the high rank of it and existence numerous of the low- order sub- basins of the higher altitudes,so that number of the high – order sub-basins is 25 % relative to low-order sub – basins.Further studies showed that, the main heavy minerals are andalusite and kyanite in the third- order sub – basins that belong to sanandaj- sirjan zone. Finally, it was revealed that the six – order basin was a consequent type.

Current research, that involves laboratory investigations into the phenomena of solubility, uses circulation equipment that has been developed to study the enlargement of joint aperture. This paper describes the preliminary results of laboratory experiments on ten different length and width of samples, which show that the flow rate through the fissures increases with time as the fissures enlarge. However, when longer samples were used, the flow rate velocity decreased as fissure enlargement decreased. The results from the analysis of the 50 tests performed indicated that the length of sample decreases as the flow rate increases, e.g. the flow rate in sample to length of 100 mm after the period of three months increases from 116.7 to 130.3 ml/s. The flow rate in sample to length of 300 mm increases from 106.1 to 111 ml/s. It was then possible to predict the relationship between enlargement of joint aperture and time, and also Furthermore, to predict the smallest joint aperture which will cause dangerous progressive solution in limestone over 90 day period. The paper shows fissures smaller than about 0.5 mm in aperture are unlikely to be dangerous in most foundation in carbonate rocks