مجله زمین شناسی مهندسی
سال یکم شماره 1 (بهار 1382)

Different methods are used for landslide hazard zonation. Some of the methods are based on specific condition of the area. In this research, applicapibility of a number of landslide hazard zonation methods in Latian Dam watershed is evaluated. For this purpose Latian Dam watershed due to variety in geological condition, engineering geological characteristics, topography, geomorphology, and precipitation was selected. Different thematic layers including geology, distance from active faults, elevation, slope rate and aspect, precipitation, and vegetation cover were prepared. More than 150 single and landslide zones were recorded based on aerial photo interpretation and field survey. The data were analyzed to find out about landslide controlling factors. Considering instability controlling factors, Nilsen, Information Value, Weight of evidence, and Density area methods were used for preparation of landslide hazard zonation in the watershed. The comparison of the prepared hazard zonation maps with landslide inventory map indicates that weight of evidence and information value methods with accuracy of 99.4 and 99.7 percent respectively are most appropriate methods for preparation of landslide hazaed zonation map in similar area in Central Alborz.

Different methods are used for landslide hazard zonation. Some of the methods are based on specific condition of the area. In this research, applicapibility of a number of landslide hazard zonation methods in Latian Dam watershed is evaluated. For this purpose Latian Dam watershed due to variety in geological condition, engineering geological characteristics, topography, geomorphology, and precipitation was selected. Different thematic layers including geology, distance from active faults, elevation, slope rate and aspect, precipitation, and vegetation cover were prepared. More than 150 single and landslide zones were recorded based on aerial photo interpretation and field survey. The data were analyzed to find out about landslide controlling factors. Considering instability controlling factors, Nilsen, Information Value, Weight of evidence, and Density area methods were used for preparation of landslide hazard zonation in the watershed. The comparison of the prepared hazard zonation maps with landslide inventory map indicates that weight of evidence and information value methods with accuracy of 99.4 and 99.7 percent respectively are most appropriate methods for preparation of landslide hazaed zonation map in similar area in Central Alborz

The spreadsheet modeling method is a practical tool for solution of the steady state, confined to the groundwater flow problems.The methodology is simple and includes many of the aspects of general flow condition such as anisotropy, heterogeneity, discharge, recharge, and irregular boundary shapes. The method incorporates numerical solution techniques for large matrices. In addition, since users program the equations in spreadsheet cells manually, the method provides good physical intuition for a groundwater flow problem. This may not always be the case when using commertial software programs. Especially it is a good teaching tool in the classroom for many students because they will understand the solution physically well. Governing equations could be developed for anisotropy and heterogeneous flow conditions. Mathematical treatment of boundary conditions is presented and the sink and sources incorporated into the domain of flow problem. The analysis shows that the solution is sensitive to the selection of the dimension of blocks or cells, node spacing and the number of iteration in spreadsheet program. Finally, advantages and limitations of solution methods are discussed in comparison with other numerical solution techniques. This method offers a number of advantages including, simplicity, accuracy and wide availability of spreadsheets such as Microsoft EXCEL. The method also has a number of limitations such as the necessity for hand programming in which viewed as shortcoming for accuracy and mistakes by handwriting and the speed of convergence of solution due to low order numerical techniques in the spreadsheet

Core samples from the sediments of the Dee Estuary were collect-ed from the chosen sites to study the distribution of pesticides in the sediments. The organic compounds were extracted by a microwave sample preparation system from 56 sediment samples and gas chromatography. Mass spectrometry (GC-MS) was employed for the organic compound analysis. Distribution of n-alkanes in the analysed sediments and calculation of their carbon preference index indicate a continental source for the organic compounds in all samples. Different search strategies were applied to find pesticides in the sediments. Maneb was the only pesticide found in the samples. The distribution of Maneb showed a zigzag pattern with depth in all the four studied areas in the Dee estuary, corresponding to the pattern of distribution of total organics. The highest concentration level of Maneb was 16.33 ng/g of sediment at a depth of 14 cm. The distribution of Maneb with depth is attributed to the seasonal application and release to the environment

The Andeka Earthquake of 25/09/2002 (Mw = 5.6) shocked the northeast region of the city of Masjed-Soleyman in Zagros folded belt. The event caused no life loss but 4 people were reported to be injured. The quake occurred in the southern parts of the Zagros belt in an oil-rich area. No damage could be observed in the Masjed-Soleyman Dam site, which is the most important hydroelectric infrastructure in the region. The region is visited and the most important damages of the earthquakes in the macroseismic region is surveyed and presented in this paper. The records of the mainshock and the aftershocks in the Dam Station were processed based on the estimation of the signal to noise ratio and the and a PGA of 360 cm/sec2 was found for the mainshock in the Dam site, at about 10km distant to epicenter.