JOURNAL OF THE EARTH
Year:2011 | Volume:6 | Issue:21|Papers Count:18

In this study, Ghar Member of Asmari Formation in three selected wells of the Doroud oil field is evaluated by using well log data. Probabilistic method was applied in petrophysical evaluation provided by Geolog 6.6 software.According to this evaluation Ghar member of Asmari formation is mainly composed of dolomite and sandstone, and using Schlumberger standard charts clay mineral is determined as illite. As results porosity (PHIE) and water saturation (SWE) are obtained 21% and 54% in average, respectively. Moreover, using distribution of petrophysical parameters, Ghar reservoir is divided to four reservoir zones named Ghar A1, Ghar A2, GharB, and Ghar C from top to the bottom. Ghar B has the best reservoir quality.

Earthquakes caused psycho-social sufferings and reducing community’s general health. Earthquake experienced in Iran underlines the need for psycho-social interventions as a part of crisis management. This paper uses the effect of such interventions on survivors’ psychological support. During and following a natural disaster, human populations are thought to be at greater risk of psychological morbidity. Post traumatic stress disorder (PTSD) may be the first reaction after disasters. This study aims to examine the efficacy of Cognitive-Behavioral Therapy (CBT) and Transactional Analysis (TA) on treatment of mothers and reducing symptoms of PTSD of their preschool aged children who had experienced Damghan Earthquake. Before and after interventions, PTSD symptoms were evaluated by using Yule’s PTSD scale. Results showed a significant decrease in children’s PTSD disorders (P<0.03).The mean scores of Yule’s PTSD scale statistically show that Psycho-social interventions in form of CBT and TA on treatment of mothers are effective in reducing post traumatic symptoms of natural disasters in preschool aged children.

The Robatkarim fault is dividable into two segments - NorthWest and SouthEast in view of the general trend of fault that is North-West and South-East with the length of 91 km. The North-West segment of fault which is located in Eocene volcanic rocks, extending from south part of Shahriar up to south part of Robatkarim with the length of 26 km. The South-East segment of it is located in upper red formation marl and extending from Robatkarim up to Asadabad mountains and Charmshahr industrial zone in south east with length of 65 Km. In the north - west of segment fault , considering of fault plane’s outcrop, normal tectonic measurements such as: strike and dip of plane, slickensides and surveying of joints, etc. In the south - east section, there are no measurable signs of the fault due to soft type of rocks In this zone the step of fault emerged in form of uplifting of upper red formation marls with Pliocene-Miocene age with respect to conglomerate formation of Kahrizak with Pleistocene-Pilocene age. Based on this research, Robatkarim fault is a high angle reverse fault with left lateral strike - slip component. We proved the left lateral displacement on north-west segment by examination of slickenside on fault plane. However, in order to be assured of this left displacement, we studied displacement and shift of drainage in south- east segment as well. The left slip displacement of the fault of Robatkarim was measured between 90-25 m whose locations were marked on the prepared geological map. Considering, the near by of seismogenic faults such as: South Ray and Garmsar faults, it is likely that the activation of any of them may cause start off of this fault. This makes the importance of Robatkarim fault twice. It is worth mentioning that the absence of large earthquake record on this fault (excepting one) can be due to non - recognition of the fault as well as scanty population in the area .Generally, historical earthquakes are not property recorded in central part of Iran because of the scanty population. Furthermore as this fault is located in central part of seismic area of Iran and as the return period of earthquakes are more longer. we can conclude that the record of one larg earthquake on this fault is not a good enough reason for non seismicity or inactivity of this fault. On the contrary, it may indicate the long period of return of this fault and therefore it can be said that the Robatkarim fault is amongst potential reactive faults.

Attenuation of seismic waves in earth is an important property to study the crustal structure. One of the most useful parameters to describe this attenuation is quality factor, that it is one of the most important parameters of seismology science. By calculating the quality factor in each area we can understand about the rate of seismic activity in that region. This quantity can be used to determine of other earthquake parameters, such as moment and magnitude. The quality factor has many applications in modeling and earthquake engineering too. These applications and the existence of high seismic risk in northeast Iran, emphasis the importance of evaluation the quality factor in this region. In this study the quality factor is evaluated beneath the local seismic networks in North East of Iran with Sato method and seisan software for 3 regions, Quchan, Mashhad and Birjand. For this purpose earthquakes recorded in these areas by the seismic network Geophysical Institute of Tehran University during the years 2006 to end of 2008 in frequency range 2 to 16 Hz are used.Finally the relations Q=98f0.83 for North Khorasan, Q=91f0.88 for Razavi Khorasan and Q=69f0.92 for South Khorasan as for determining the quality factors have been proposed. The results have been compared with similar studies in other regions of Iran. Thus the NE region has more seismic activity than NW of Iran and Bam region but it has less seismic activity than Tehran area.

A sequence of the Upper Devonian age (Frasnian-Lower Famennian) on the western side of Zard Mountain is located near the Zefreh village. W of central Iran Basin (ca. 65 km NE of Esfahan). It is composed of five lithostratigraphic units, including two lowermost sandstone and three uppermost carbonate unites. Sandstones are mainly quartz arenite in composition. Low percentage of feldspar. Unstable minerals and presence of heavy minerals (Zircon and Turmaline) suggests high weathering rate in source region, the high weathering rate in samples. Revealed by petrographic studies and, CIW index as well, suggests a warm humid climate. The geochemical and modal data analysis of sandstones samples, plotted on the discriminate function diagrams determined the quartzose recycled provenance and reveals that the source material was deposited on a passive margin tectonic setting, after transport and recycling.

Landslide in this study was surveyed by dividing the area into several equal regions which later were classified in terms of real risk resulted of sliding of strata. Such procedure which is accompanied with simplifying the effects and evaluation of instability agents led to providing the landslide risk map of the area. In order to prepare this map, first data was gathered and effective parameters on instability were identified. Then this parameters including lithology of study area, slop of area, aspect of the slop, average annual rainfall, distance from faults and earthquake acceleration were processed in Arc GIS9.2 software and the quality parameters were quantified with each data layer divided into smaller classes. In the next stage, specific weights were assigned to each class and risk value of each parameter was determined. Finally, they were presented as a landslide hazard map.

T waves propagate in the so-called SOFAR channel of minimum sound velocity centered on 1200 meters depth acting as a waveguide for acoustic energy in the world’s oceans. They can be excited by sources in the solid earth such as earthquakes through conversion of seismic energy into acoustic waves at the solid- liquid interfaces. As a particular form of seismic waves emanating from an earthquake, T waves can provide insight into seismic sources in the ocean environment. Considering the application of this phase to detect small earthquakes in marine basins and ability to yield information on source rupture and detect submarines by using the small explosion and analysis of this phase and also using of this phase in modeling of Tsunami earthquake study on T waves is an essential. Study on T waves shows p and s or surface waves conversions occurs offshore. So it can be travel hundreds of kilometers away from the coastline. Indeed, when the seismic waves resulting from receiver-side conversion is of sufficient amplitude, it can be felt by the population close to shore even though the source of the acoustic energy maybe thousands of kilometers away. For instance, large earthquake in Sumatra in 2004 on Maldives was occurred was this group. Remarking that there is no study of T waves in Iran, investigation of this phase can open up new opportunities for the investigation of acoustic sources, including earthquakes, in the ocean environment.

The Kerman’s structural situation and the Shahdad’s structural junction, is located in Central Iran, which caused the influence of field stress that results from convergent and collision between the Arabia and Eurasia Plates. Concentration of the fault and fold structures with the north northwest-south southeast trend indicates stress concentration in this area. The Nayband, Gowk, Lakarkuh and Ravar right lateral strike-slip faults with the north-south trend as well as Kohbanan, Behabad, Anduhjerd with the northwest -southeast trend convergent had raised expectation about earthquake concentration in this area of the Kerman Province. However, at the latter decades, some parts of Gowk and Kohbanan faults were increasing their seismic activities. The reason may be related to the special structural characteristics of the faults. Forming up the block faulting with different sizes and forming some junction areas between the fault structures was the reason for distributing stress and different structural behavior. For this reasons, at the Shahdad’s structural junction some parts of Gowk faults and around Zarand along the Kohbanan fault, there are concentration of seismic activities. The Mesozoic units and Neogene sedimentary deposits folding as well as anti clock rotation some blocks faulting are appeared at the Shahdad’s structural junction area. These seem as reactions of compressional stress affected on the north-south direction in this area.

Complexity in the structural characters of surface in mountainous areas with complicated topography and the effect of difference in travel time between first break and reflected wave have introduced new methods of static corrections.in this article the static corrections is done in 3 steps: LVL static corrections, intermediate reference datum corrections, and uniform datum corrections. Additionally in each step qualitative control which results the elimination of possible errors and qualitative enhancement of final static corrections will be applied. for evaluation of this method, with series of data obtained from a mountainous area in oil field at south of Iran, which has complicated topography including a fault, in order to solve the LVL static corrections, Inversion of first break model is combined with tomographic inversion. Then according to the first break analysis on normal shot records and tomographic inversion, replacement velocity of intermediate reference datum is obtained. Finally, replacement velocity of uniform datum is obtained from average value coming from tomographic inversion.

The reflection of seismic waves from subsurface layers illuminates potential hydrocarbon accumulations. As waves reflect, their amplitudes change to reveal important information about the underlying materials. Seismic reflection amplitude information can be used to invert for the relative impedances of the materials on the both sides of the interface.By correlating these seismically derived properties with values measured in the borehole, interpreters may be able to extend well information throughout the entire seismic volume. This process can help fill gaps in our knowledge of formation properties between wells and reduce risk in the exploration, development and production operations.In this study, by inverting the pseudo 3D data of Kangan and Upper-Dalan gas horizons and using gamma ray, density and P-wave logs, we can probe acoustic impedance and then porosity, Poisson’s ratio and Vp/Vs ratio model.

The Ruteh Formation in Seyed Abad section in Southern flank of Aynehvarzan-Dalichai anticline in Central Alborz with a thickness of 115 meters was studied for lithostratigraphy and biostratigraphy reviews. In this section the Ruteh Formation includes dark gray limestone with intercalation of dark gray shale. The Ruteh Formation is underlain by the Doroud Formation with disconformably and overlain by bauxite and laterite attributed of Nessen Formation (Early Djulfian). Determined foraminifera indicate an Late Permian (Kuergandian-Murgabian) age of the Ruteh formation.

Mahabad area (Googtapeh and Khalifan) with about 154 km2 width is located in Mahabad – Marivan zone in southern part of west Azarbayejan province. Comments range from the geological study has been located Sanandaj-Sirjan Zone including Mahabad, Bayandor and Soltanieh Dolomite formations Precambrian in age and Zaigun, Mila and Barut formation Cambrian in age. This form of the promising areas of Mahabad 1:100000 sheet is therefore more accurate for exploratory studies has been reviewed. Review results with the anomaly described elements and heavy mineral dispersion very good overlap between the four groups, there are elements of the first group include: Au and paragenesis it, the second group Pb-Zn, the third group Ba-Bi-Cu and fourth group Co is that the two check statistical variable (Histograms correlation) and multivariate analysis including cluster analysis and factor conforms convention.

The Daralu copper deposit is located in Kerman province and in intrusive - volcanic belt, Urumieh-Dokhtar. Petro graphic studies indicate to exist Rhyodacite porphyry, Silicified Granodiorite porphyry, Micro Granodiorite, Tonalite and Rhyolite rocks. Altration studies shows that sericitization, chloritization, silicification, epidotization, and propylitization are exist in the area. The kinds of mineralization are disseminated, open space filling texture and with skeletal Quartz vein lets. Study of polished sections shows that minerals like Pyrite, Chalcopyrite, Sphalerite, Bornite, Covellite, Chalcocite, Magnetite, Hematite, Limonite, Jarosite, Manganese oxides, Malachite and Azurite are exist in this area.

South Pars gas field, is one of the field in south west of Iran in the Zagros Sedimentary basin. In this evaluation we have checked properties suchas porosity, water saturation, shale volume and lithology. Lithology of Kangan Formation in zone K1 consists of anhydrite, dolomite to limy dolomite and dolomitic limestone with some shale and average effective porosity in this zone is 8.6%, average effective water saturation is 16.6% and average shale volume is 3.6%. Lithology of zone K2 consists of limestone to dolomitic limestone, dolomite with some anhydrite and shale. Average effective porosity in this zone is 9.4%, average effective water saturation is 12.4% and average shale volume is 0.4% holds reservoir potential. Lithology of Upper Dalan Formation in zone K3 consists of dolomitic limestone, dolomite to limy dolostone with some anhydrite and shale. Average effective porosity in zone K3 is 7.5%, average effective water saturation is 11.5% and average shale volume is 7.9%. Lithology zone K4 consists of limestone to dolomitic limestone, dolomitic to limy dolostone and anhydrite with some shale. In this zone Average effective porosity 11.8%. Average effective water saturation is 10.3% and average shale volume is 2.7% holds reservoir potential.

Polrood reservoir dam is located at southeast of the Roodsar city in the Gilan Province. The objective of this article is to identify and evaluate the environmental risks of the Polrood dam in construction phase. For this purpose, the risk factors were first identified by experts’ judgments using the Delphi questionnaire. Then, the Analytical Hierarchy Process (AHP) was used for weighting and classification of the Polrood dam risk factors.In this process, after building the hierarchical structure, the pair-wise comparison matrices for the risks criteria were created according to the risks intensity and probability. In order to determine the weight of each criterion, the values obtained were entered into the Expert Choice software. Based on the results of this software, “Physicochemical risks”, “Biological risks”, “Economic-Social-Cultural risks” and “Health and Safety risks” were ranked weighting 0.123, 0.080, 0.048 and 0.021 respectively. Among the Physicochemical risks, “Erosion”, “Sedimentation” and “Pollutions” were identified as the most important risks, weighting 0.061, 0.047 and 0.018 respectively. For the biological risks, the negative impacts were most on the “Flora”, and then on the “Habitats” and “Fauna”, weighting 0.189, 0.139 and 0.017 respectively. The most important risks among the Economic-Social-Cultural risks were “Displacement and resettlement”, “Negative impacts on buildings, facilities and residential areas” and “Land use change”, weighting 0.114, 0.049 and 0.033 respectively. “Workers downfall”, “Road accidents” and “Sudden explosions”, weighting 0.109, 0.046 and 0.044 were also considered as the most important “Health and Safety risks”. Finally, some useful solutions and management programs proposed to reduce, eliminate, control, and transferring the main risk factors.

Cretaceous sediments in the Zefreh section in the northeast of Esfahan is 364 meters thickness and consist of massive to thin bedded limestone and silty/limy shale. Its lower boundary with the Shemshak Formation and its upper boundary with the Eocene conglomerate is unconformity. Facies analysis of Cretaceous sediments in the Zefreh section indicate deposition in the tidal flat, lagoon, barrier and deep marine facies belts in a rimmed shelf platform. Cretaceous sediments in the Zefreh section consis of six depositional sequences. The first four depositional sequences related to early cretaceous, the fifth depositional sequence related to early to late cretaceous and the sixth depositional sequence related to late cretaceous. The lower contact of first sequence and the upper contact of sixth sequence are type 1 unconformity (SB1) and the other contacts between the sequences are type 2 unconformity (SB2). These depositional sequences consist of transgressive and highstand systems tract.