Earth Science

Desertification is a complex phenomenon which reduces the soil fertility involving ecological and economic processes that characterise the environment at different geographic scale. The MEDALUS model identifies regions that are environmentally sensitive area (ESAs). In this model, different types of ESAs to desertification can be analyzed in terms of various parameters such as landforms, soil, geology, vegetation, climate, and human actions. About 80% of IRAN is located in arid and semi-arid region and third of its area is exposed to the threat of desertification with attention turning to the increasing area of deserts on IRAN, it is necessary to first identify areas liable to desertification before identifying mitigation and control measures. For this purpose it is necessary to prepare a desertification map as a guide for planners. In this study to evaluate the desertification condition regarding to local conditions of the study area, six indices of water, climate, soil, vegitation, management and wind erosion erosion were selected and assessment of desertification condition was conducted Based on these indices, weightening and MEDALUS model. The results showed that climate with average of 1.9 and wind erosion with 1.68 have the highest effects. Soil with average of 1.28 and Water with average of 1.31 have the lowest effect on the desertification process in the study area. almost 32.86% of study area was located in the very high class, 65.9% was located in high class and 1.24% was located in moderate class of desertification.

Different soil erosion types including water and wind erosion which result in soil degradation and reducing fertility potential of soil, cause desertification in the region. "Gully Erosion" is one of water erosion types that with progressive trend results in soil degradation, and on the other hand, produces a lot of sediments. Determination of effective factors on gully erosion and its hazard zonation is one of substantial approaches in order to manage and control this phenomenon, and select the most appropriate and applied effective option. Hence this study is performed to classify effective factors on gully erosion, and identify regions with high potential in gully erosion using analytical hierarchy process method in Neyzar region, Qom. The most effective factors in gully erosion including slope degree, slope aspect, lithology, land use, and land suitability, were collected and digitized in geographical information systems. Then, gullies inventory map prepared using 1:20000 aerial photos (1372), and field studies was carried out by GPS. In the next step, effective factors were compared in pairs, and the weight of each factor was calculated that illustrates their contribution. Next, scaled map of each factor in respect to their quantities was prepared, and finally, gully erosion was zoned using scaled layers and scale index related to each factor. Results indicate that lithology (0.4978), and land use (0.2227) are the most important factors in gully initiation, respectively. For the assessment of zonation map, gullies inventory map shows that about 91% of gullies are located in zones of high and very high risk in this region. Therefore, due to the fact that AHP is based on dual comparision of factors, results in easy and accurate necessery calculations and it includes many effective factors, it is a suitable and efficient method for gully erosion hazard zonation.

The World cannot exist without Water. It is an important component to human survival. Water should be purified for a better life style. It is the basic duty of every individual to conserve water resources. Nagavati watershed is located in a part of Dharmapuri district of Tamil Nadu in South India. It lies between latitudes 11°45’N to 12°15’ N and 77°30’ E to 78°30 E longitudes. It covers within the Survey of India toposheet nos. 57H/16, 57L/4, 58E/13, and 58I/1 covering an area of about 500 sq.km. Fourty six representative groundwater samples were collected from pre-monsoon season during 2015 and those water samples were analysed by standard analytic methods and physical and chemical parameters such as pH, Electrical Conductivity, Total Dissolved Solids, Alkalinity, Hardness, Na+, K+, Ca2+, Mg2, Cl , HCO3, CO3 , SO4, NO3 and F. Correlation study indicates that different parameters are strongly interrelated. The correlation and regression provide an excellent tool for the prediction of parameter values within a reasonable degree of accuracy.

Estimation of Aquifer Hydraulic properties and protective capacity of overburden units in groundwater aquifers of Nkanu-West local government area, Enugu state has been carried out. The project area lies within latitude 060 25I 00IIN to 060 38I 00IIN and longitudes 0070 13I 00IIE to 0070 24I 00IIE with an area extent of about 489.4sqkm, over two main geological formations. A total of seventy-eight Vertical Electrical Sounding (VES) were acquired within the study area, employing the Schlumberger configuration. Resistivity and thickness of aquiferous layers were obtained from the interpreted VES data, using the INTERPEX resistivity software. The resistivity and depth to aquiferous layer varied from 50 to 1250?m and 40 to 180m respectively across the study area. Knowing resistivity and thickness, it was possible to compute transverse resistance and the longitudinal conductance. Using the relationship between transverse resistance and transmissivity, it was possible to estimate the aquifer hydraulics (transmissivity and the hydraulic conductivity) and the protective capacity of overburden units from VES data. Transmissivity ranges from 15m2/day to 140m2/day while hydraulic conductivity ranges from 0.5m/day to 8.0m/day. Based on transmissivity classifications, the study area is rated low to moderate groundwater potentials. The longitudinal conductance (ranging from 0.01?-1 to 20?-1) of the area enabled the protective capacity of the aquifer to be classified as moderate to good. Contour variation maps of apparent resistivity, overburden depth, transverse resistance, longitudinal conductance, aquifer transmissivity and hydraulic conductivity were constructed. The various constructed contour maps, the estimated aquifer hydraulics and overburden protective capacity, will serve as a useful guide for groundwater exploration and development in the study area.

Flood has today become a major disaster ravaging communities in different parts of the world, especially those lying around the banks of rivers. But most importantly, flooding occurs when the natural waterways are obstructed due to human quest for “development”. However, Physical Planning Agencies as well as many communities are now becoming more aware of the need to embrace best environmental management practices in order to avert the recurring colossal damages of flooding. Therefore, this paper set out to evaluate the physical planning measures adopted in controlling flooding in Kubwa town of the Federal Capital Territory, Abuja. In order to achieve this, a direct interview session was held with the representative of the Development Control Department (DCD) of the Federal Capital Development Authority (FCDA) and also, a total of 100 questionnaires were administered on household heads or their representatives-representing 20% of the about 500 houses that were affected by the 2009 flooding. The primary data obtained was subsequently analysed using the descriptive statistical methods and the result revealed that the FCDA is to blame for granting legal titles for developers to build on the flood plain of river Usuma; this is because 60% of the houses submerged by the 2009 flooding have either C of Os or statutory right of occupancy. Owing to this therefore, the paper recommended that the FCDA should take a major step in addressing the situation through the enforcement of physical planning policies and the sensitization of the members of the public on how best to ensure a flood-free society by embracing environmental best practices.

Radiation that coming from the natural radionuclides such as 226Ra (238U), 228Ra (232Th) and 40K can cause health risks if exposed for longer terms. The activity and radiological effect parameters of these natural radionuclides were determined in rock samples from Bukit Bunuh. The results of measurements showed that the average activity concentration of 226Ra varied from 22.5 to 42.3 Bq kg-1, for 228Ra, it varied from 1.2 to 3.5 Bq kg-1 and for 40K, it varied from 274.3 to 438.2 Bq kg-1. Based on the available data, the radiation hazard parameter is calculated. The external gamma dose rate calculated from the concentration of the three radionuclides ranged from 29.8 to 38.7 nGy h-1. Three calculated parameters from the activity concentration values, i.e. the radium equivalent activity (Raeq) range between 59.3 and 78.6 Bq kg-1 (mean 68.1 Bq kg-1), the representative level index (I?r) range between 0.46 and 0.59 (mean 0.50) and the external hazard index (Hex) range between 0.17 and 0.21 (mean 0.20). This is well below the recommended value of 370 Bq kg-1 (for Raeq) and unity (for Hex). The annual effective dose rate of the areas was determined to be between 0.037 and 0.048 mSv y-1. The results show that there are no significant health hazards to humans.

A seismological investigation for earthquake hazard in the Greater Accra Metropolitan Area was undertaken. The research was aimed at employing a mathematical model to estimate the seismic stress for the study area by generating a complete, unified and harmonized earthquake catalogue spanning 1615 to 2012. Seismic events were sourced from Amponsah, P., Leydecker, G. and Muff R. (2012) based on Ambraseys and Adams, (1986), Geological Survey Department (GSD), Ghana Atomic Energy Commission’s National Data Center (NDC), National Earthquake Information Service (NEIS), United States Geological Survey (USGS) and the International Seismological Centre (ISC).The least square estimation method and the maximum likelihood estimation method were employed to evaluate b-values of 0.6 and 0.9 respectively for the study area. A thematic map of epicentral intensity was developed to help relate the distribution of events with respect to the virtually fractured, jointed and sheared geology of the Greater Accra Metropolitan Area (GAMA). The results obtained are indicative of the fact that the stress level of GAMA has a telling effect on its seismicity and also the events are prevalent at fractured, jointed and sheared zones of weakness.

The paper focused on assessment of perception on climate change associated disasters, adaptations and resources for future opportunities based on human perceptions. Stratified random sampling was used for selecting respondents between north and southern Gashua. Fifty (50) respondents from the south and thirty eight (38) from the North were selected. The data was collected via field observation and structured interviews at the onset of the rainy season of 2011. The result revealed that, drought, wind storm, heat wave, hamattan dust, tree biodiversity reduction, flood and out-break of some heat related meningitis are among the major disasters aggravating the social well-beings of the populace. Among the reasons perceived for the disasters were massive deforestation, overgrazing due to communal resource feeling, nearness to desert, poverty, and societal immorality .Field observation revealed that, the inhabitants have adapted to the environmental challenges by practicing irrigation, fishing, rearing livestock, seasonal regional and local migration to southern Nigeria, reverting to traditional architectures, planting exotic tree species, civil service and intensive prayers for Devine intervention in their various religious gatherings. The study recommends among others, Agro- forestry intensification practice using draught- resistant tree species and massive participatory rural- integrated projects towards improvement of social amenities, economic diversifications through collaboration of NGOS, CBOS and local authorities, for the ample dry land resources-based opportunities witnessed in the study area.

The study area is a part of the Mid Ganga Basin that lies in Patna district, Bihar state. It is made up of thick (>300 m) pile of sediments comprising layered sequences of sand, silt and clay deposits. Within the layered sequences, medium to coarse sand beds are embedded which form aquifers. The annual normal rainfall of the area is 1200 mm, 86% of which takes place during monsoon period spanning between June and September. High Arsenic concentrations (> 50 ppb) have been reported from the several blocks of the Patna districts including Maner. The present work deals with the study of hydrogeological aspects arsenic contamination of the Maner Block of the Patna district. The present study is an attempt to decipher relationship between arsenic occurrences and its relation with other major elements present in the area. Relation between different elements is understood by preparing graphs. It is seen that Fe, HCO3 and Arsenic (As) generally indicates the increase of concentrations towards Ganga River. Higher concentrations of arsenic (> 50 ppb) were encountered mainly in the newer alluvium (T0), whereas the Older Alluvium appears to be arsenic free.

Sedimento logical analysis methods to study historical events and environmental sections of these dimentary basins of the natural sciences is common. Analysis of sedimentary sections particularly Quaternaryse dements can be revealed climatic and environmental conditions of the area and uncover favorable view of the environmental conditions. The purpose of this study is Analysis of Bayazeh sediments and Chopanan sediments and explanation of their formation environment. In this study the physical properties of these diments containing Granulometry, Analysis, Calcimetry, Transparent rate, rounding rate and chemical properties, including the amount of lime, pH, EC were compared and the results indicated that Chopanan sediments were aeolian sediments and deposited in dry environment and Bayazeh sediments deposits in an aquatic environment. This causes indicate that in the past era there was a local pond in the Bayazeh.