Remote sensing applications to geological problems in Egypt: case study, slope instability investigation, Sharm El-Sheikh/Ras-Nasrani Area, Southern Sinai   总被引：2，自引：1，他引：1  

Ahmed M. Youssef  Norbert H. Maerz  Abdallah Mohamed Hassan 《Landslides》2009,6(4):353-360

The Sharm El-Sheikh/Ras-Nasrani area is one of the most attractive tourist resorts in Egypt particularly and in the world in general. The area has been rapidly growing during the last few years. Many construction projects including villages, hotels, beaches, and roads have recently been undertaken. The following study demonstrates the use of high-resolution satellite images, QuickBird imagery, acquired on June 2nd, 2007 (0.61 m spatial resolution), for detailed mapping of the recent developments and the slope instability hazard zones. The results were confirmed by field reconnaissance. Our findings indicate that there are many development areas threatened by unstable zones. The hazard areas have been delineated and classified, and a final slope instability hazard map has been established. Different factors were found to have a crucial impact on the slope instability, some natural and others man-made. These unstable localities need to be remediated and/or monitored to avoid any loss in property and/or lives.  相似文献   

Determining optimum number of geotechnical testing samples using Monte Carlo simulations     

Kerry Magner  Norbert Maerz  Ivan Guardiola  Adnan Aqeel 《Arabian Journal of Geosciences》2017,10(18):406

Knowing how many samples to test to adequately characterize soil and rock units is always challenging. A large number of tests decrease the uncertainty and increase the confidence in the resulting values of design parameters. Unfortunately, this large value also adds to project costs. This paper presents a method to determine the number of samples as a function of the coefficient of variation. If, as in the case of a reliability-based design, the resistance factors are a function of the coefficient of variation of the measurements, then lowering the coefficient of variation (COV) can result in lowering of the resistance factor resulting in a less conservative design. In this study, laboratory samples were isolated by specific unified soil classification system soil type and general site location. A distribution was fitted for each of the geotechnical parameters measured. For each scenario, groups of 2, 3, 4, 5, 10, 15, 20, 30, 50, and 100 random samples were generated by using Monte Carlo simulations from the fitted distributions. For each group, the variability was calculated in terms of the COV. In all cases, the COV decreased as the sample size increased. However, the rate of decrease for the COV was the greatest at a low number of samples; it becomes increasingly smaller at a higher number of samples.  相似文献   

Tracing and dating recent chemical transfers in weathering profiles by trace-element geochemistry and U---U---Th disequilibria: the example of the Kaya lateritic toposequence (Burkina-Faso)     

Franois Chabaux  Olivier Dequincey  Jean-Jacques Lvque  Jean-Claude Leprun  Norbert Clauer  Jean Riotte  Hlne Paquet 《Comptes Rendus Geoscience》2003,335(16):1219-1231

The paper presents a synthesis of the approach recently developed to constrain the nature and the age of recent element mobility in weathering profiles. The approach relies on a comparison of variations of trace elements and U-series disequilibria in weathering profiles. It is exemplified in the case of old lateritic profiles from the Kaya toposequence, Burkina Faso. Trace elements and ²³⁸U---²³⁴U---²³⁰Th disequilibria have been analysed in whole rock samples from two pits located in very contrasted topographical positions. Trace element data show that the whole toposequence is marked by an intense chemical remobilization, including uranium, from the cap to the lower part of the profiles. ²³⁸U---²³⁴U---²³⁰Th disequilibrium data outline that all the levels of the profiles are affected by recent U---Th fractionations, and that each level of the toposequence is marked by U gains and losses. The chronological approach developed in this paper leads to an age of about 400 kyr for the dismantling of the iron cap, and ages ranging from 0 to 400 kyr for U accumulation in the pink clay horizon of the profiles. The depth repartition of U accumulation in the profile implies that the remobilisation processes in this toposequence varied through time, on time constants similar to those of climatic variations. To cite this article: F. Chabaux et al., C. R. Geoscience 335 (2003).  相似文献   

A study of the M2 tide in the Arctic Ocean     

Dr. Zugmunt Kowalik  Dr. Norbert Untersteiner 《Ocean Dynamics》1978,31(6):216-229

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Upper Precambrian and lowermost Plaeozoic correlatinos in West Africa and in the Western Part of Central Africa. Probable diachronism of the Late Precambrian tillite     

Max Deynoux  Roland Trompette  Norbert Clauer  Jean Sougy 《International Journal of Earth Sciences》1978,67(2):615-630

The Late Precambrian or Eocambrian and the lowermost part of Palaeozoic rocks of West Africa and of the Western half of Central Africa include two lithostratigraphic sequences of sediments which we can identify as well on the craton as in the orogenic belts. The lower sequence, argillaceous, green colour, sometimes flyschoid, begins with a tillite or a mixtite. The upper sequence made of reddish, mainly continental sandstones, represents in some areas the molasse of the Pan-African Fold Belt.These two sequences, and notably at the base of the first one the tillite horizon, seem to be older in the South (Katangan and West-Congolian Chains) than in the North (Adrar of Mauritania). This diachronism is thought to be related to polar wandering, the South pole having shifted in that interval of time from South-Africa to West of the Senegal coast.

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Zusammenfassung Das obere Präkambrium oder Eokambrium und die Basis des Paläozoikums von Westafrika und im westlichen Teil von Zentralafrika sind aus zwei lithostratigraphischen Abfolgen gebildet, die gleichfalls auf den Kratonen und in den Gebirgsketten zu erkennen sind. Die untere feinklastische Abfolge, grün, manchmal flyschartig, beginnt mit einem Tillit oder einem Mixtit. Die obere rote, sandige Abfolge, kontinentalen Ursprungs, wird örtlich als eine von der pan-afrikanischen Orogenese gebildete Molasse angesehen.Diese beiden Abfolgen, besonders die Tillite, scheinen diachron und im Süden älter (Katangische und West-Kongolische Gebirgsketten) als im Norden (Adrar von Mauritanien) zu sein. Diese Verjüngung nach Norden kann mit einer Polwanderung in Verbindung gebracht werden; der Südpol zieht während dieser Zeit von Südafrika in das Gebiet westlich der senegalesischen Küste.

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Résumé Le Précambrian terminal ou Eocambrien et la base du Paléozoïque de l'Afrique de l'Ouest et de la partie occidentale de l'Afrique centrale comprennent deux ensembles lithostratigraphiques identifiables aussi bien dans les couvertures cratoniques que dans les chaînes. L'ensemble inférieur, argileux, vert, parfois flyschoïde, débute par une tillite ou une mixtite. L'ensemble supérieur, gréseux, rouge, à dominante continentale, est interprété dans certaines zones comme la molasse de la chaîne pan-africaine. ces deux ensembles, et en particulier la tillite á la base du premier, semblent plus anciens au Sud (chaînes katangienne et ouest-congolience) qu'au Nord (Adrar de Mauritanie). Cet âge plus jeune vers le Nord va de Pair avec le mouvement du pôle sud, qui, â époque, se déplace de l'Afrique du Sud au large des côtes du Sénegal.

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Über einen möglichen Zusammenhang zwischen Hangform und Schichtlagerung im Opalinuston auf Blatt Heidenheim     

Norbert Tschierske 《Rock Mechanics and Rock Engineering》1977,9(1):43-53

ZusammenfassungÜber einen möglichen Zusammenhang zwischen Hangform und Schichtlagerung im Opalinuston auf Blatt Heidenheim Es wurde ein Rechenprogramm entwickelt, um aus den Höhenlinien einer topographischen Karte die Form eines Hangabschnittes zu bestimmen. Drei unterschiedliche Hangformen können festgestellt werden: Normalhänge, KX-Hänge, bei denen die mittleren Hangpunkte signifikant oberhalb einer durch die übrigen Hangpunkte gelegten Ausgleichskurve liegen, und KV-Hänge, bei denen die mittleren Punkte signifikant unterhalb der Ausgleichskurve liegen.Bei einer Anwendung des Verfahrens auf Hänge einer 70 m bis 80 m mächtigen Tonschicht im Süddeutschen Schichtstufenland zeigt sich eine Übereinstimmung zwischen Hangform und Schichtlagerung: Normalhänge treten bevorzugt bei waagerechter Schichtlagerung auf, KX-Hänge bei hangauswärts fallenden Schichten. Eine Deutung des Befundes wird versucht.

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SummaryOn a Possible Connection Between the Form of Slopes and the Bedding Dip in the Al (1) Clay of Heidenheim A computer program has been developed to determine the character of a slope segment by the contour lines of the topographical map. Three different characters of slope can be distinguished: 1) normal slope, 2) the KX-slope, in which the points around the middle of the slope lie significantly above an approximation curve defined by the points above and below the middle section, and 3) the KV-slope, in which the points around the middle of the slope lie significantly below this curve.The application of this program on slopes in a bed of clay, 70–80 m thick, in the Süddeutsches Schichtstufenland (cuesta landscape) reveals a correspondence between the character of the slope and the bedding dip: There is a predominance of normal slopes in horizontal strata, whereas KX-slopes prevail in strata declining from level in the sense of the slope (consequent slope). An interpretation of this result is attempted.

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RésuméSur un rapport possible entre la forme d'un versant et la position des couches dans l'argile al (1) de Heidenheim Un programme-ordinateur a été développé pour déterminer la forme d'un segment d'un versant à l'aide des courbes de niveau d'une carte topographique. Trois formes de versant différentes peuvent être constatées: 1) le versant normal, 2) le versant KX, dans lequel les points au milieu du versant sont situés d'une manière très significative au-dessus d'une ligne (trouvée d'après la méthode des moindres carrés) qui est déterminée par le reste des points, 3) le versant KV, dans lequel les points au milieu sont situés d'une manière très significative au-dessous de cette ligne.L'application de ce programme sur des versants en argile d'une épaisseur de 70 à 80 m en Süddeutsches Schichtstufenland (côte) montre une correspondance entre la forme du versant et la position des couches: Les versants normaux dominent dans les couches horizontales, les versants KX dominent dans les couches qui s'inclinent dans la même direction que le versant (versant conséquent). Une interprétation de ce résultat est essayée.

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A Blind Comparison Between Results of Four Image Analysis Systems Using a Photo-Library of Piles of Sieved Fragments     

John-Paul Latham  John Kemeny  Norbert Maerz  Michael Noy  Jacques Schleifer  Simon Tose 《Fragblast: International Journal for Blasting and Fragmentation》2003,7(2):105-132

Four image analysis systems for measuring rock fragmentation: FragScan, PowerSieve®, Split and WipFrag, have been compared under conditions necessary to provide an objective though limited assessment of their capabilities. The analysis of results is based on a sample of ten photographs taken from a series of photographs of controlled artificial muckpiles. These were created from dumping a blended mixture of sieved samples of limestone aggregate, in order to create a range of near perfect Rosin-Rammler sieve size distributions. Results from the various systems are compared with sieved results using both histogram and cumulative forms, with and without fines corrections in the case of Split and Wipfrag. Statistical indicators are evaluated to examine the match between system prediction values and sieving values. Commentaries on the results by the inventors of each system have been incorporated. All four systems were found to perform both well in some cases and poorly in others. From a detailed examination of the results, some insight into the strengths and weaknesses of the various systems is presented.  相似文献   

Late Quaternary climatic control on erosion and weathering in the eastern Tibetan Plateau and the Mekong Basin     

Zhifei Liu  Christophe Colin  Alain Trentesaux  Giuseppe Siani  Norbert Frank  Dominique Blamart  Segueni Farid 《Quaternary Research》2005,63(3):769-328

High-resolution siliciclastic grain size and bulk mineralogy combined with clay mineralogy, rubidium, strontium, and neodymium isotopes of Core MD01-2393 collected off the Mekong River estuary in the southwestern South China Sea reveals a monsoon-controlled chemical weathering and physical erosion history during the last 190,000 yr in the eastern Tibetan Plateau and the Mekong Basin. The ranges of isotopic composition are limited throughout sedimentary records: ⁸⁷Sr/⁸⁶Sr = 0.7206–0.7240 and ε_Nd(0) = −11.1 to −12.1. These values match well to those of Mekong River sediments and they are considered to reflect this source region. Smectites/(illite + chlorite) and smectites/kaolinite ratios are used as indices of chemical weathering rates, whereas the bulk kaolinite/quartz ratio is used as an index of physical erosion rates in the eastern Tibetan Plateau and the Mekong Basin. Furthermore, the 2.5–6.5 μm/15–55 μm siliciclastic grain size population ratio represents the intensity of sediment discharge of the Mekong River and, in turn, the East Asian summer monsoon intensity. Strengthened chemical weathering corresponds to increased sediment discharge and weakened physical erosion during interglacial periods. In contrast, weakened chemical weathering associated with reduced sediment discharge and intensified physical erosion during glacial periods. Such strong glacial–interglacial correlations between chemical weathering/erosion and sediment discharge imply the monsoon-controlled weathering and erosion.  相似文献   

Landscape evolution and geodynamic controls in the Gulf of Cadiz (Huelva coast, SW Spain) during the Late Quaternary     

Cari Zazo  Norbert Mercier  Pablo G. Silva  Cristino J. Dabrio  Jos Luis Goy  Elvira Roquero  Vicente Soler  Francisco Borja  Javier Lario  Dolores Polo  Luis de Luque 《Geomorphology》2005,68(3-4):269-290

The coastal evolution of the El Abalario area (Huelva, southern Spain) during the Late Pleistocene and Holocene is reinterpreted after a refinement of the available geochronology by means of optically stimulated luminescence (OSL) dating. New data come from the analysis of soft sediment deformation, palaeosols, geomorphological mapping, and published seismic surveys on the onshore and offshore Gulf of Cadiz.The present structure of El Abalario dome resulted from the complex interaction of littoral-catchment processes and sea-level changes upon an emergent coastal plain, conditioned by the upwarping of the underlying Pliocene–Pleistocene prograding deltaic sequence. Upwarping is probably related to escape of over-pressurized fluids, accompanied by dewatering, prior to (?) and during OIS (Oxygen Isotopic Stage) 5. Continued upwarping produced the large NW–SE gravitational fault of Torre del Loro (TLF) in the southwestern flank of the dome, roughly parallel to the present coastline during OIS 5–OIS 4. The resulting escarpment favoured the accumulation of aeolian sand dunes (units U1, U2, and U3) from OIS 5 to early OIS 1. Unit U1 (OIS 5) ends upwards in a supersurface with a thick weathering profile that suggests moist and temperate climatic conditions. Unit U2 accumulated mainly during OIS 4 and OIS 3 with prevailing W/E winds. The supersurface between U2 and U3 records a part of OIS 2, with relative low sea level. Sedimentation of unit U3 took place during the Last Deglaciation (radiocarbon and OSL ages) with prevailing W/SW winds, under a temperate moist climate, that became more arid towards the top (Holocene). A major supersurface with an iron crust-like layer (SsFe) developed during the Holocene Climatic Optimum (OIS 1) under wetter and more temperate conditions than before, fossilizing the TLF. The supersurface is covered by younger aeolian dunes (U4, U5, U6, and U7) transported by W–SW winds since the Late Neolithic–Chalcolithic cultural period (5.0 ky cal BP).  相似文献   

European VOC Emission Estimates Evaluated by Measurements and Model Calculations     

øystein Hov  Asgeir Sorteberg  Norbert Schmidbauer  Sverre Solberg  Frode Stordal  David Simpson  Anne Lindskog  Hans Areskoug  Pedro Oyola  Heikki Lättilä  Niels Z. Heidam 《Journal of Atmospheric Chemistry》1997,28(1-3):173-193

Observations and model calculations of the concentration of hydrocarbonsat five Scandinavian rural sites during March–June 1993are reported.Decreasing concentrations from March to June are observedat all sites. The highest concentrations of hydrocarbons were found in air massescoming in from the southwest to southeast, indicating that long rangetransport fromcontinental Europe and the U.K. is important in pollution episodes. An episode of elevated concentrations of hydrocarbons observed at three of the sites in the middle of Marchis described and discussed in relation to the synoptic situation and thepresenceof other chemical compounds (NO₂, PAN, total nitrate andozone).A Lagrangian numerical model is used to calculate the concentrations of theindividual hydrocarbons at the fivesites and comparison with observations is made.The calculated concentrations for nonmethane hydrocarbons with quite longchemicallifetimes agree well with the observations.For the sum of observed and calculated hydrocarbons the correlationcoefficientsare in the range of 0.65–0.88 for the five sitesand the ratio between calculated and measured concentrations was0.72–0.97, indicating thatthe European VOC emission inventory is quite well estimated.  相似文献