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201.
Masyhur Irsyam Donny T. Dangkua Hendriyawan Drajat Hoedajanto Bigman M. Hutapea Engkon K. Kertapati Teddy Boen Mark D. Petersen 《Journal of Earth System Science》2008,117(2):865-878
This paper presents the development of spectral hazard maps for Sumatra and Java islands, Indonesia and microzonation study for Jakarta city. The purpose of this study is to propose a revision of the seismic hazard map in Indonesian Seismic Code SNI 03-1726-2002. Some improvements in seismic hazard analysis were implemented in the analysis by considering the recent seismic activities around Java and Sumatra. The seismic hazard analysis was carried out using 3-dimension (3-D) seismic source models (fault source model) using the latest research works regarding the tectonic setting of Sumatra and Java. Two hazard levels were analysed for representing 10% and 2% probability of exceedance (PE) in 50 years ground motions for Sumatra and Java. Peak ground acceleration contour maps for those two hazard levels and two additional macrozonation maps for 10% PE in 50 years were produced during this research. These two additional maps represent short period (0.2 s) and long-period (1.0 s) spectra values at the bedrock. Microzonation study is performed in order to obtain ground motion parameters such as acceleration, amplification factor and response spectra at the surface of Jakarta. The analyses were carried out using nonlinear approach. The results were used to develop contour of acceleration at the surface of Jakarta. Finally, the design response spectra for structural design purposes are proposed in this study. 相似文献
202.
The summer monsoon season of the year 2006 was highlighted by an unprecedented number of monsoon lows over the central and
the western parts of India, particularly giving widespread rainfall over Gujarat and Rajasthan. Ahmedabad had received 540.2mm
of rainfall in the month of August 2006 against the climatological mean of 219.8mm. The two spells of very heavy rainfall
of 108.4mm and 97.7mm were recorded on 8 and 12 August 2006 respectively. Due to meteorological complexities involved in replicating
the rainfall occurrences over a region, the Weather Research and Forecast (WRF-ARW version) modeling system with two different
cumulus schemes in a nested configuration is chosen for simulating these events. The spatial distributions of large-scale
circulation and moisture fields have been simulated reasonably well in this model, though there are some spatial biases in
the simulated rainfall pattern. The rainfall amount over Ahmedabad has been underestimated by both the cumulus parameterization
schemes. The quantitative validation of the simulated rainfall is done by calculating the categorical skill scores like frequency
bias, threat scores (TS) and equitable threat scores (ETS). In this case the KF scheme has outperformed the GD scheme for
the low precipitation threshold. 相似文献
203.
Janette Tourney Bryne T. Ngwenya J.W. Fred Mosselmans Laurence Tetley Gregory L. Cowie 《Chemical Geology》2008,247(1-2):1-15
This study investigated proton adsorption to an extracellular polymeric substance (EPS) producing bacterial strain, Bacillus licheniformis S-86, in order to characterise and quantify the contribution made by EPS to cell surface reactivity. Potentiometric titrations were conducted using both untreated cells and cells from which the EPS layer had been extracted. Surface-complexation modelling indicated the presence of four different functional groups in both untreated and EPS-free cells. These sites are assigned to phosphodiester, (pKa 3.3–3.4), carboxylic (pKa 5.3–5.4), phosphoryl/ (pKa 7.4–7.5) and hydroxyl/amine (pKa 9.9–10.1) type groups. The pKa values for the four groups were very similar for untreated and EPS-free cells, indicating no qualitative difference in composition, but site concentrations in the untreated cells were statistically found to be significantly higher than those in the EPS-free cells for the pKa 3.3–3.4 and pKa 9.9–10.1 sites. Infrared analysis provided supporting evidence that site 2 is carboxylic in nature but did not reveal any difference in IR absorption between the native and EPS-free cells. Dissolved organic carbon (DOC) analysis conducted during this study indicated that DOC release by cells is significant, and that the EPS layer is the major contributor. 相似文献
204.
Doline probability map using logistic regression and GIS technology in the central Ebro Basin (Spain) 总被引:3,自引:0,他引:3
In the surroundings of Zaragoza, karstification processes are especially intense in covered karst areas where fluvial terraces
lie directly on Tertiary evaporites. Since the beginning of Quaternary, these processes have lead to the development of collapse
and subsidence dolines with a wide range of sizes, which have significant economic impacts. To reduce economic impact and
increase safety, a regional analysis of this phenomenon is needed for spatial management. Therefore, a probability map of
dolines was developed using logistic regression and geographic information system (GIS) techniques. This paper covers the
selection of input data, manipulation of data using the GIS technology, and the use of logistic regression to generate a doline
probability map. The primary variable in the doline development in this area is geomorphology, represented by the location
of endorheic areas and different terrace levels. Secondary variables are the presence of irrigation and the water table gradient. 相似文献
205.
Zaragoza city is located in the central Ebro Basin, in the Iberian Peninsula. The fluvial terraces formed by the Ebro River
present a valuable resource of sand and gravel deposits. However, taking advantage of these available resources implies conflicts
with other land use interests like urban and industrial development as well as agricultural use, which has also traditionally
occupied the alluvial terraces. These deposits represent a substantial groundwater resource that should be preserved for future
generations. The development of spatial decision support systems (SDSS) has greatly assisted efforts for solving land-use
conflicts. These systems combine the benefits of geographic information systems (GIS) and decision support methodologies and
are therefore suitable to manage sustainable development of urban areas. In this contribution, an extraction suitability map
taking into consideration a variety of environmental criteria is created with the help of a SDSS. The method used is the analytical
hierarchy process which is integrated in ArcGIS. Areas most suitable to sand and gravel extraction are located in the high
terraces, and in those terraces covered by pediments where the thickness of resource is relatively high. These areas are far
from valuable natural areas, outside areas most vulnerable to groundwater contamination, and beneath soils with poor irrigation
characteristics. 相似文献
206.
S. Miko G. Koch S. Mesić M. Šparica-Miko M. Šparica R. Čepelak A. Bačani P. Vreča T. Dolenec S. Bergant 《Environmental Geology》2008,55(3):517-537
Due to their balneotherapeutic features, the organic-rich sediments in Makirina Cove are an important source of healing mud.
An environmental geochemistry approach using normalization techniques was applied to evaluate the anthropogenic contribution
of trace metals to sediments used as healing mud. Sediment geochemistry was found to be associated with land-use change and
storm events, as well as with proximity of a road with heavy traffic in the summer months. Local valley topography preferentially
channels lithogenic and pollutant transport to the cove. Concentrations and distribution of trace metals indicate lithogenic
(Ni, Cr, Co) and anthropogenic (Pb, Cu, Zn and Se) contributions to the sediments. The calculation of enrichment factors indicates
a moderate (EFs between 2–3.5) input of anthropogenic Cu and Pb in surficial sediments to a depth of 10 cm. Patients using
the Makirina Cove sediments as healing mud could be to some extent exposed to enhanced uptake of metals from anthropogenic
sources via dermal contact. 相似文献
207.
The Cu–Co–Ni Texeo mine has been the most important source of Cu in NW Spain since Roman times and now, approximately 40,000 m3 of wastes from mine and metallurgical operations, containing average concentrations of 9,263 mg kg−1 Cu, 1,100 mg kg−1 As, 549 mg kg−1 Co, and 840 mg kg−1 Ni, remain on-site. Since the cessation of the activity, the abandoned works, facilities and waste piles have been posing
a threat to the environment, derived from the release of toxic elements. In order to assess the potential environmental pollution
caused by the mining operations, a sequential sampling strategy was undertaken in wastes, soil, surface and groundwater, and
sediments. First, screening field tools were used to identify hotspots, before defining formal sampling strategies; so, in
the areas where anomalies were detected in a first sampling stage, a second detailed sampling campaign was undertaken. Metal
concentrations in the soils are highly above the local background, reaching up to 9,921 mg kg−1 Cu, 1,373 mg kg−1 As, 685 mg kg−1 Co, and 1,040 mg kg−1 Ni, among others. Copper concentrations downstream of the mine works reach values up to 1,869 μg l−1 and 240 mg kg−1 in surface water and stream sediments, respectively. Computer-based risk assessment for the site gives a carcinogenic risk
associated with the presence of As in surface waters and soils, and a health risk for long exposures; so, trigger levels of
these elements are high enough to warrant further investigation. 相似文献
208.
A new method of estimating the ratio between in situ rock stresses and tectonics based on empirical and probabilistic analyses 总被引:1,自引:0,他引:1
This paper describes a new procedure for assessing the ratio between in situ stresses in rock masses by means of K (K = σH / σv, being σH and σv principal stress) and tectonics for purposes of engineering geology and rock mechanics. The method combines the use of the logic decision tree and the empirical relationship between the Tectonic Stress Index, TSI, and a series of K in situ values obtained from an extensive database. The decision tree considers geological and geophysical factors affecting stress magnitudes both on the regional and local scale. The TSI index is defined by geological and geomechanical parameters. The method proposed provides an assessment of the magnitude of horizontal stresses of tectonic origin. Results for several regions of Europe are presented and the possible applications of the procedure are discussed. 相似文献
209.
A. A. Krylov O. M. Khlystov T. I. Zemskaya H. Minami A. Hachikubo H. Shoji M. Kida T. P. Pogodaeva L. Naudts J. Poort 《Geochemistry International》2008,46(10):985-995
This paper presents data on authigenic siderite first found in surface sediments from mud volcanoes in the Central (K-2) and Southern (Malen’kii) basins of Lake Baikal. Ca is the predominant cation, which substitutes Fe in the crystalline lattice of siderite. The enrichment of the carbonates in the 13C isotope (from +3.3 to +6.8‰ for the Malen’kii volcano and from +17.7 to +21.9‰ for K-2) results from the crystallization of the carbonates during methane generation via the bacterial destruction of organic matter (acetate). The overall depletion of the carbonates in 18O is mainly inherited from the isotopic composition of Baikal water. 相似文献
210.
G. Caro V.C. Bennett B. Bourdon T.M. Harrison A. von Quadt S.J. Mojzsis J.W. Harris 《Chemical Geology》2008,247(1-2):253-265
146Sm–142Nd and 147Sm–143Nd systematics were investigated in garnet inclusions in diamonds from Finsch (S. Africa) and Hadean zircons from Jack Hills (W. Australia) to assess the potential of these systems as recorders of early Earth evolution. The study of Finsch inclusions was conducted on a composite sample of 50 peridotitic pyropes with a Nd model age of 3.3 Ga. Analysis of the Jack Hills zircons was performed on 790 grains with ion microprobe 207Pb/206Pb spot ages from 3.95 to 4.19 Ga. Finsch pyropes yield 100 × ?142Nd = ? 6 ± 12 ppm, ?143Nd = ? 32.5, and 147Sm/144Nd = 0.1150. These results do not confirm previous claims for a 30 ppm 142Nd excess in South African cratonic mantle. The lack of a 142Nd anomaly in these inclusions suggests that isotopic heterogeneities created by early mantle differentiation were remixed at a very fine scale prior to isolation of the South African lithosphere. Alternatively, this result may indicate that only a fraction of the mantle experienced depletion during the first 400 Myr of its history. Analysis of the Jack Hills zircon composite yielded 100 × ?142Nd = 8 ± 10 ppm, ?143Nd = 45 ± 1, and 147Sm/144Nd = 0.5891. Back-calculation of this present-day ?143Nd yields an unrealistic estimate for the initial ?143Nd of ? 160 ?-units, clearly indicating post-crystallization disturbance of the 147Sm–143Nd system. Examination of 146,147Sm–142,143Nd data reveals that the Nd budget of the Jack Hills sample is dominated by non-radiogenic Nd, possibly contained in recrystallized zircon rims or secondary subsurface minerals. This secondary material is characterized by highly discordant U–Pb ages. Although the mass fraction of altered zircon is unlikely to exceed 5–10% of total sample, its high LREE content precludes a reliable evaluation of 146Sm–142Nd systematics in Jack Hills zircons. 相似文献