Integrated methodology for flood risk assessment and application in urban communities of Pakistan

Flood disasters and its consequent damages are on the rise globally. Pakistan has been experiencing an increase in flood frequency and severity along with resultant damages in the past. In addition to the regular practices of loss and damage estimation, current focus is on risk assessment of hazard-prone communities. Risk measurement is complex as scholars engaged in disaster science and management use different quantitative models with diverse interpretations. This study tries to provide clarity in conceptualizing disaster risk and proposes a risk assessment methodology with constituent components such as hazard, vulnerability (exposure and sensitivity) and coping/adaptive capacity. Three communities from different urban centers in Pakistan have been selected based on high flood frequency and intensity. A primary survey was conducted in selected urban communities to capture data on a number of variables relating to flood hazard, vulnerability and capacity to compute flood risk index. Households were categorized into different risk levels, such as can manage risk, can survive and cope, and cannot cope. It was found that risk levels varied significantly across the households of the three communities. Metropolitan city was found to be highly vulnerable as compared to smaller cities due to weak capacity. Households living in medium town had devised coping mechanisms to manage risk. The proposed methodology is tested and found operational for risk assessment of flood-prone areas and communities irrespective of locations and countries.     

Lower-Middle Triassic rocks in the Enmynveem River (western Chukotka)

The Lower-Middle Triassic section of the Enmynveem River dated on the basis of macrofauna includes three genetic types of sediments with different structural-textural features: (1) sediments of high-density autokinetic flows; (2) sediments of low-density turbidity flows; and (3) background sediments with thin interlayers of fine-grained turbidites. It has been established that sandy-silty sediments of all three genetic types formed on the continental slope in deep-water conditions, but their accumulation was related to the erosion of rocks in various provenances. Some sediments were formed as the result of the erosion of proximal volcanic complexes, whereas other sediments were related to the erosion of metamorphic rocks on the distal continental land.     

Preparing a seismic hazard model for Switzerland: the view from PEGASOS Expert Group 3 (EG1c)

The seismic hazard model used in the PEGASOS project for assessing earth-quake hazard at four NPP sites was a composite of four sub-models, each produced by a team of three experts. In this paper, one of these models is described in detail by the authors. A criticism sometimes levelled at probabilistic seismic hazard studies is that the process by which seismic source zones are arrived at is obscure, subjective and inconsistent. Here, we attempt to recount the stages by which the model evolved, and the decisions made along the way. In particular, a macro-to-micro approach was used, in which three main stages can be described. The first was the characterisation of the overall kinematic model, the “big picture” of regional seismogenesis. Secondly, this was refined to a more detailed seismotectonic model. Lastly, this was used as the basis of individual sources, for which parameters can be assessed. Some basic questions had also to be answered about aspects of the approach to modelling to be used: for instance, is spatial smoothing an appropriate tool to apply? Should individual fault sources be modelled in an intraplate environment? Also, the extent to which alternative modelling decisions should be expressed in a logic tree structure has to be considered.     

Part II. Evaluation of Ar-Ar quartz ages: Implications for fluid inclusion retentivity and determination of initial Ar/Ar values in Proterozoic samples

The argon isotope systematics of vein-quartz samples with two different K-reservoirs have been evaluated in detail. Potassium is hosted by ultra-high-salinity fluid inclusions in quartz samples from the Eloise and Osborne iron-oxide-copper-gold (IOCG) deposits of the Mt Isa Inlier, Australia. In contrast, K is hosted by accidentally trapped mica within lower-salinity fluid inclusions of a sample selected from the Railway Fault, 13 km south of the Mt Isa copper mine, Australia. Imprecise apparent ages have been obtained for all of the samples studied and conclusively demonstrate that quartz fluid inclusions are retentive to Ar and have not leaked over billions of years. IOCG samples that host K in fluid inclusions only, have K/Cl values of <1 and the ages obtained represent the maximum ages for mineralization. In contrast, the Railway Fault samples that include accidentally trapped mica have K/Cl values of ?1. Excess ⁴⁰Ar_E plus Cl hosted by fluid inclusions, and radiogenic ⁴⁰Ar_R plus K, are strongly correlated in these samples and define a plane in 3D ⁴⁰Ar-³⁶Ar-K-Cl space. In this case, the plane yields an ‘excess ⁴⁰Ar_E’ corrected age of ∼1030 Ma that is 100’s of Ma younger than nearby Cu-mineralization at Mt Isa. The age is interpreted to reflect ⁴⁰Ar-loss from the accidentally trapped mica into the surrounding fluid inclusions, and is not related to the samples’ age of formation. The initial ⁴⁰Ar/³⁶Ar value of fluid inclusions is widely used to provide information on fluid origin. For the IOCG samples that host K in fluid inclusions only, the initial ⁴⁰Ar/³⁶Ar values are close to the measured values at every temperature of stepped heating experiments. For samples that include accidentally trapped mica, the correction for post-entrapment radiogenic ⁴⁰Ar_R production is significant. Furthermore, because ³⁹Ar_K present in accidentally trapped mica crystals is released at different temperatures to radiogenic ⁴⁰Ar_R lost to the surrounding fluid inclusions, intra-sample ⁴⁰Ar/³⁶Ar variation cannot be reliably documented. The results demonstrate that noble gas analysis is readily applicable to Proterozoic, or older, samples but that if K-mineral impurities are present within quartz the abundance of K must be determined before calculation of mean ⁴⁰Ar/³⁶Ar values that are representative of the samples’ initial composition.     

Cornetite: Modulated densely-packed Cu2+ oxysalt

Summary The crystal structure of cornetite, Cu₃(PO₄)(OH)₃, orthorhombic, a = 10.854(1), b = 14.053(3), c = 7.086(2), Å, V = 1080.8(3) ų, Z = 8, space group Pbca, has been refined to an R-index of 3.9% for 1231 observed reflections (I > 3I), measured with MoK X-radiation on an automated four-circle diffractometer. The structure consists of edge sharing zig-zag chains of distorted octahedra, cross-linked by edge-sharing octahedral dimers into complex octahedral layers. Adjacent layers are corner-linked together by neighbouring octahedra and PO₄ tetrahedra into a densely-packed heteropolyhedral framework, in which the phosphate tetrahedra share edges with the octahedral dimers. The polyhedral layers exhibit a commensurate modulation that results from the interaction between local relaxation of Jahn-Teller distorted octahedra and the long-range requirements of translational periodicity.

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Cornetit: Ein moduliertes, dicht gepacktes Oxosalz des zweiwertigen Kupfers

Zusammenfassung Die Kristallstruktur des Cornetits, Cu₃(PO4)(OH)3, orthorhombisch, a = 10,854(1), b = 14,053(3), c = 7,086(2,) Å, V = 1080,8(3) ų, Z = 8, Raumgruppe Pbca, wurde mit 1231 beobachteten Röntgenreflexen (I > 3I), die mit MoK-Strahlung auf einem automatischen Vierkreis-Diffraktometer gesammelt worden waren, auf einen R-Wert von 3,9% verfeinert. Die Struktur besteht aus kantenverknüpften Zickzack-Ketten verzerrter Oktaeder, die über kantenverknüfte Oktaeder-Dimere zu komplizierten Oktaederschichten verbunden sind. Benachbarte Schichten sind über Ecken durch benachbarte Oktaeder und PO₄-Tetraeder zu einem dichtgepackten, heteropolyedrischen Gerüst verknüpft, in welchem die Phosphattetraeder mit den Oktaeder-Dimeren Kanten gemeinsam haben. Die Polyederschichten zeigen eine kommensurable Modulierung, die aus der Wechselwirkung zwischen der lokalen Relaxation von Jahn-Teller-verzerrten Oktaedern und den Forderungen der translatorischen Periodizität über größere Entfernungen resultiert.

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With 5 Figures     

Evolution of the Landscape of the Western Part of the Turan–Uyuk Basin (Tuva Highland) in the Late Pleistocene

Doklady Earth Sciences - A complex of works including geomorphological deciphering, field survey, drilling, electric prospecting, and dating of deposits using the radiocarbon method and optically...     

Earthquake response of asymmetric building with MR damper

Plan asymmetric buildings are very susceptible to earthquake induced damage due to lateral torsional coupling, and the corners of these systems suffer heavy damage during earthquakes. Therefore, it is important to investigate the seismic behavior of an asymmetric plan building with MR dampers. In this study, the effectiveness of MR damper-based control systems has been investigated for seismic hazard mitigation of a plan asymmetric building. Furthermore, the infl uence of the building parameters and damper command voltage on the control performance is examined through parametric study. The building parameters chosen are eccentricity ratio and frequency ratio. The results show that the MR damper-based control systems are effective for plan asymmetric systems.     

Geochemical surveillance of active volcanoes: data on the fumaroles of Vulcano (Aeolian Islands,Italy)

Temperature and chemical composition of condensates of higher temperature fumaroles, located on the rim of the crater of Vulcano, were studied over a period of one year. Maximum temperature changed from 216°C (June 1977) to 291°C (May 1978). HCl is the main constituent of condensates which, in comparison with data from fumaroles of other volcanoes, contain also noteworthy quantities of boron and bromine. Since these chemical characteristics suggested the possible inflow of water of marine origin into the volcanic conduit, experimental data on seawater-rock reactions at high temperatures and pressures were taken into account. A model is drafted for the volcanic system, in which the occurrence of an aquifer interposed between the magma chamber and the surface is considered. The vaporization of this aquifer would feed the fumaroles giving rise, through different mixing processes with surface waters, to the observed differences in temperature and chemical composition. However, data available at present are not sufficient to support the proposed model, which must be mainly considered as a working hypothesis.     

Distribution, source and evolution of nitrate in a glacial till of southern Alberta, Canada

This paper addresses the distribution, origin and controls upon nitrate in a 30-km² area of the Interior Great Plains Region of southern Alberta, Canada. High concentrations of nitrate (> 100 mg l⁻¹ NO⁻₃-N) occurred in several isolated enclaves below the water table in brown weathered till. Nitrate concentrations of over 300 mg l⁻¹-N were encountered in groundwater samples collected from these enclaves. Low nitrate concentrations (< 1.1 mg l⁻¹ NO⁻₃-N) were also encountered in the weathered till upgradient and downgradient of the nitrate enclaves. Groundwater samples collected from the underlying grey nonweathered till and bedrock had NO⁻₃-N concentrations of < 1.1 mg l⁻¹.

Through the application of geochemical (NO⁻₃-N and NH⁺₄-N) studies, environmental isotope studies (tritium), microbial analyses (nitrifiers) and laboratory experiments, it was shown that the high nitrates found in the weathered till are the result of the oxidation of ammonium present within the tills. It is postulated that this oxidation occurred during the Holocene epoch when water tables were much lower than present-day levels (5–18 m, and 2 m below ground, respectively).

Through the use of Eh measurements, the enumeration of denitrifying bacteria and laboratory experiments, the potential for denitrification was shown to exist below the present-day water table in the weathered till as well as in the nonweathered till and bedrock. Isotopic data showed that less denitrification may be occurring within the nitrate enclaves than in adjacent downgradient areas.