Joint use of TEM and MRS methods in a complex geological setting     

Anatoly Legchenko  Michael Ezersky  Christian Camerlynck  Abdallah Al-Zoubi  Konstantinos Chalikakis 《Comptes Rendus Geoscience》2009,341(10-11):908-917

Transient Electromagnetic (TEM), known also as Time Domain Electromagnetic (TDEM) and Magnetic Resonance Sounding (MRS) methods were applied jointly to investigate variations in lithology and groundwater salinity in the Nahal Hever South area (Dead Sea coast of Israel). The subsurface in this area is highly heterogeneous and composed of intercalated sand and clay layers over a salt formation, which is partly karstified. Groundwater is very saline, with a chloride concentration of 100–225 g/l. TEM is known as an efficient tool for investigating electrically conductive targets like saline water, but it is sensitive to both the salinity of groundwater and the porosity of rocks. MRS, however, is sensitive primarily to groundwater volume, but it also allows delineating of lithological variations in water-saturated formations. MRS is much less sensitive to variations in groundwater salinity in comparison with TEM. We show that MRS enables us to resolve the fundamental uncertainty in TEM interpretation caused by the equivalence between groundwater resistivity and lithology. Combining TEM and MRS, we found that the sandy Dead Sea aquifer filled with Dead Sea brine is characterized by a bulk resistivity of ρ_x > 0.4 Ωm, whereas zones with silt and clay in the subsurface are characterized by a bulk resistivity of ρ_x < 0.4 Ωm. These observations are confirmed by calibration of the TEM method performed near 18 boreholes.  相似文献   

Environmental impact assessment inside and around Mahd Adh Dhahab gold mine, Saudi Arabia     

Abdallah S. Al-Hobaib  K Q. Al-Jaseem  Hassan M. Baioumy  Ahmed H Ahmed 《Arabian Journal of Geosciences》2011,5(5):985-997

Environmental impact of the mining activities in the Mahd Adh Dahab gold mine was examined through detailed chemical analyses of a number of samples represent the gold-bearing rocks, soils, dust, and plants from inside and outside the mine area and within the Mahd City as well as the surrounding areas. The obtained data were compared with the standard values of heavy metals concentrations in order to evaluate the pollution levels of these activities on the different systems around the mine area. The data of rock samples shows relatively high concentrations of Cu (up to 11.9%), Pb (up to 4.1%), and Zn (up to 14.2%), which attributed to the outcropping of the sulfide-bearing veins on the surface of the mine area. Soil samples inside the mine area show high concentrations of Zn, Cu, Cd, Pb, and As compared to those from outside the mine indicating pollution impact of the mine activities on soils from inside the mine with these elements. Dust samples collected from inside the mine have considerably high concentrations of Cd, Zn, and Pb compared to those from outside the mine. Values of heavy metals in the collected dust from outside the mine are comparable with those from many big cities including Riyadh City, Saudi Arabia, indicating contaminations with heavy metals to the dust from inside the mine at Mahd Adh Dahab City. Heavy metals concentrations in the stems and leaves samples of the various types of plants inside and outside Mahd Adh Dahab gold mine area show that they have relatively higher concentrations of Cu and Zn compared to other metals. Stem samples show relatively higher concentrations of Zn, Cu, Cr, and V compared to the leaves samples. Although values of most heavy metals in the plants, both stems and leaves, are comparable with those of the typical levels of heavy metals in plants, Co and Cr show relatively higher concentrations suggesting a pollution impact of the mine activities in plants with Co and Cr. As a conclusion, results indicated that the contamination effect of Mahd Adh Dahab gold mine activities are clear in soils and dusts inside the mine area with some metals such Zn, Cu, Cd, and Pb due to their relatively enrichment in mineralization. Therefore, careful treatments of the waste dump materials inside the mine area are recommended to protect soils and air contaminations and to prevent the extension of pollution outside the mine in the future.  相似文献   

Landslides induced by the 2017 Mw7.3 Sarpol Zahab earthquake (Iran)     

Cheaib  Aya  Lacroix  Pascal  Zerathe  Swann  Jongmans  Denis  Ajorlou  Najmeh  Doin  Marie-Pierre  Hollingsworth  James  Abdallah  Chadi 《Landslides》2022,19(3):603-619

Landslides are the main secondary effects of earthquakes in mountainous areas. The spatial distribution of these landslides is controlled by the local seismic ground motion and the local slope stability. While gravitational instabilities in arid and semi-arid environments are understudied, we document the landslides triggered by the Sarpol Zahab earthquake (November 12, 2017, Mw7.3, Iran/Iraq border), the largest event ever recorded in the semi-arid Zagros Mountains. An original earthquake-induced landslide inventory was derived, encompassing landslides of various sizes and velocities (from rapid disrupted rockfalls to slow-moving coherent landslides). This inventory confirms the low level of triggered landslides in semi-arid environments. It also displays clear differences in the spatial and volumetric distributions of earthquake-induced landslides, having 386 rockfalls of limited size triggered around the epicenter, and 9 giant (areas of ca. 10⁶ m²) active and ancient deep-seated landslides coseismically accelerated at locations up to 180 km from the epicenter. This unusual distant triggering is discussed and interpreted as an interaction between the earthquake source properties and the local geological conditions, emphasizing the key role of seismic ground motion variability at short spatial scales in triggering landslides. Finally, the study documents the kinematics of slow-moving ancient landslides accelerated by earthquakes, and opens up new perspectives for studying landslide triggering over short (~?1–10 years) and long-time (~?1000–10,000 years) periods.

  相似文献   

Seismic site effect estimation using microtremor studies in the archaeological city of Jerash in Jordan     

Waleed Eid Olimat 《《地质学报》英文版》2018,92(Z1):270-270

  相似文献   

The Neoproterozoic volcanic complex of the Boumalne inlier (Saghro massif,Eastern Anti-Atlas; Morocco): petrological and geochemical characteristics     

Rachida Bendaoud  M’hamed El Janati  Mohamed Elaatmani  Luisa Carvalho  Zaineb Hajjar  Said Ilmen  Abdallah Algouti  Ahmed Algouti  Lahcen Khouchaf 《Arabian Journal of Geosciences》2018,11(17):512

Neoproterozoic volcanic series are exposed in the northern edge of the Saghro massif (Eastern Anti-Atlas, Morocco). Four volcanic rock types (basalt, andesite, dacite, and rhyolite) were distinguished in the Boumalne inlier within the so-called Saghro volcanic sequences based on petrographic and geochemical observations. Boumalne volcanic rocks contain high Al₂O₃, Fe₂O₃, Ba, Sr, Zr, Rb, and Nb contents, including calc-alkaline affinity in composition. Boumalne volcanic rocks are similar to other lower-Neoproterozoic volcanic rocks such Agouiniy formation in Sirwa inlier and in other parts of Bou-Azzer inlier. Indeed, they indicate an active subduction signature. The geochemical data show a LREE enrichment compared to HREE. The fractional crystallization has played a major role during the evolution of the magma. The less-siliceous dacitic rocks could have been formed after a low degree of partial melting of mafic parental magma source, whereas the rich-siliceous rhyolite may have been derived from dacitic magma source by a higher degree of fractional crystallization.  相似文献   

Geologic controls of submarine groundwater discharge: application of remote sensing to north Lebanon     

Amin Shaban  Mohamad Khawlie  Chadi Abdallah  Ghaleb Faour 《Environmental Geology》2005,47(4):512-522

Typical of Mediterranean countries, the Lebanese shoreline is well known for its littoral and offshore groundwater discharges, the so-called submarine springs. The tectonic framework of the terrain explains its interruption by dense geologic structures, i.e., fracturing, faulting, karstic routes, as well as acute dips of rock strata seaward. All of these structures serve as hydrologic agents transporting groundwater to the sea. The study aims to locate these groundwater discharges, and to interpret their geologic controls on land. For this purpose, two major lines of approach were followed. The first is an airborne thermal infrared (TIR) survey using radiometers to identify thermal anomalies, thereby determining the exact location of submarine groundwater discharges (SGDs). The second line of approach is the analysis of satellite images (Landsat 7ETM⁺) to delineate the geologic features that govern the mechanism of water flow, thereby determining their sources on land. Twenty-seven major SGDs were identified, 10 of these being offshore springs, the others littoral springs. The springs show a large variety of discharge configurations and extents, mainly parallel or perpendicular to the shoreline or rounded. Three major structural controls were identified to contribute to the transport of groundwater to the sea. These are karstic galleries, faults, and tilted rock strata, their contributions being 48, 37, and 15%, respectively. The SGDs associated with linear passageways, i.e., karstic galleries and faults, are connected with land aquifer formations several kilometers away from the shoreline. Moreover, the presence of impervious rock formations at many localities along the coastline results in a confined hydrologic system, promoting the flow of SGDs into the sea.  相似文献   

Compaction characteristics of granular soils in United Arab Emirates     

Maher Omar  Abdallah Shanableh  Adnan Basma  Samer Barakat 《Geotechnical and Geological Engineering》2003,21(3):283-295

Most of the topsoils encountered in United Arab Emirates and in the Arabian Peninsula are granular soils with small percentages of silt and clay. Determination of the compaction characteristics of such soils is an essential task in preparing for construction work. The accumulating experience over many years of soil testing in our laboratories suggested that there exists an underlying trend that governs the compaction characteristics of such soils. As such, a study was undertaken to assess the compaction characteristics of such soils and to develop the governing predictive equations. For the purposes of this study, 311 soil samples were collected from various locations in the United Arab Emirates, and tested for various including grain-size distribution, liquid limit, plasticity index, specific gravity of soil solids, maximum dry density of compaction, and optimum moisture content following ASTM D 1557-91 standard procedure C. Following the development of the predictive equations, a new set of 43 soil samples were collected and their compaction results were used to test the validity of predictive model. The range of variables for these soils were as follows: percent retained on US sieve #4 (R#4): 0–68; Percent passing US sieve #200 (P#200): 1–26; Liquid limit: 0–56; Plasticity index: 0–28; Specific gravity of soil solids: 2.55–2.8. Based on the compaction tests results, multiple regression analyses were conducted to develop mathematical models and nomographic solutions to predict the compaction properties of soils. The results indicated that the nomographs could predict well the maximum dry density within ±5% confidence interval and the optimum moisture content within ±3%. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

A comparative study of various commercially available programs in slope stability analysis   总被引：1，自引：0，他引：1  

Wael Alkasawneh  Abdallah I. Husein Malkawi  Jamal Hassan Nusairat  Nermeen Albataineh   《Computers and Geotechnics》2008,35(3):428-435

The objective of this paper is to study the effect of different slip surface search techniques on the factors of safety obtained using the limit equilibrium (LE) slope stability methods. This objective is accomplished by comparing results from the finite element method, the linear grid method, the rectangular grid method, and the Monte-Carlo searching techniques using different commercially available programs. The results showed that the LE methods are very efficient methods when coupled with a robust searching technique namely the Monte-Carlo method. In addition, the selected slip surface search technique highly influenced the location of the critical slip surfaces as well as the value of the calculated factors of safety.  相似文献   

A multi‐label cellular automata model for land change simulation          下载免费PDF全文

Omar Charif  Hichem Omrani  Fahed Abdallah  Bryan Pijanowski 《Transactions in GIS》2017,21(6):1298-1320

The use of cellular automata (CA) has for some time been considered among the most appropriate approaches for modeling land‐use changes. Each cell in a traditional CA model has a state that evolves according to transition rules, taking into consideration its own and its neighbors’ states and characteristics. Here, we present a multi‐label CA model in which a cell may simultaneously have more than one state. The model uses a multi‐label learning method—a multi‐label support vector machine, Rank‐SVM—to define the transition rules. The model was used with a multi‐label land‐use dataset for Luxembourg, built from vector‐based land‐use data using a method presented here. The proposed multi‐label CA model showed promising performance in terms of its ability to capture and model the details and complexities of changes in land‐use patterns. Applied to historical land use data, the proposed model estimated the land use change with an accuracy of 87.2% exact matching and 98.84% when including cells with a misclassification of a single label, which is comparably better than a classical multi‐class model that achieved 83.6%. The multi‐label cellular automata outperformed a model combining CA and artificial neural networks. All model goodness‐of‐fit comparisons were quantified using various performance metrics for predictive models.  相似文献   

Evaluation of Methods Used for Reducing Heavy Metal Leaching from Sandy Soil   总被引：1，自引：0，他引：1  

Maher Omar  Abdallah Shanableh 《Geotechnical and Geological Engineering》2016,34(5):1413-1423

Excessive heavy metal content in sandy soils poses risk to human health and the environment. The rapid expansion of urban areas makes it imperative to manage contaminated sites so that land can be reclaimed for beneficial purposes. Several methods have been proposed to control the leaching of heavy metals from contaminated soils. In this study, four techniques for mobilization and immobilization of metals in sandy soil were compared. The assessed mobilization techniques included chemical extraction using aqueous solutions of acids and chelating agents as well as biochemical extraction using sulfur-oxidizing microorganisms. The evaluated immobilization techniques included lime-cement-pozzolan stabilization and natural-zeolite stabilization. The immobilization techniques do not involve removing metals from soil and instead focus on addition of substances to the soil that alter its composition, volume, and properties. On the other hand, mobilization techniques entail the removal of metals from soil and changes in the soil properties. The findings confirmed that both mobilization and immobilization are effective in controlling the leaching of metals from sandy soils and thereby minimize the risk to the environment and human health. However, the appropriate technique for application at a given site should be chosen on a case-by-case basis, while accounting for the economic and technical feasibility, the necessary level of cleanup, and effect of residual metals on human health and the environment.  相似文献