Description of an aerodynamic levitation apparatus with applications in Earth sciences

Background  

In aerodynamic levitation, solids and liquids are floated in a vertical gas stream. In combination with CO₂-laser heating, containerless melting at high temperature of oxides and silicates is possible. We apply aerodynamic levitation to bulk rocks in preparation for microchemical analyses, and for evaporation and reduction experiments.     

Hydrochemistry and Classification of Groundwater Resources of Ishwardi Municipal Area,Pabna District,Bangladesh

The chemical property of groundwater depends largely on the mineralogical composition of the rocks through which the water has moved and the rate of movement and these characteristics of surface water depend on organic and inorganic reactions, industrial effluents, rainfall and temperature etc. The underground water tends to contain more dissolved materials than those in surface water because of their more intimate and longer contact with organic materials of soil and rock particles. The groundwater of the studied area is dominant of alkaline earth’s (Ca²⁺ and Mg²⁺) and weak acids (HCO₃ ⁻) which may be classified as Magnesium-Bicarbonate and Calcium Carbonate types. Genetically, the groundwater of the area belongs to both “Normal Chloride” “Normal Sulphate” and “Normal Carbonate” to “Super Carbonate” group. Based on EC, SAR and RC, the groundwater of the area varies from good–excellent quality for irrigation purposes with low alkali hazard and medium salinity hazard.     

Pilot Block Method Methodology to Calibrate Stochastic Permeability Fields to Dynamic Data

In the present paper, a new geostatistical parameterization technique is introduced for solving inverse problems, either in groundwater hydrology or petroleum engineering. The purpose of this is to characterize permeability at the field scale from the available dynamic data, that is, data depending on fluid displacements. Thus, a permeability model is built, which yields numerical flow answers similar to the data collected. This problem is often defined as an objective function to be minimized. We are especially focused on the possibility to locally change the permeability model, so as to further reduce the objective function. This concern is of interest when dealing with 4D-seismic data. The calibration phase consists of selecting sub-domains or pilot blocks and of varying their log-permeability averages. The permeability model is then constrained to these fictitious block-data through simple cokriging. In addition, we estimate the prior probability density function relative to the pilot block values and incorporate this prior information into the objective function. Therefore, variations in block values are governed by the optimizer while accounting for nearby point and block-data. Pilot block based optimizations provide permeability models respecting point-data at their locations, spatial variability models inferred from point-data and dynamic data in a least squares sense. A synthetic example is presented to demonstrate the applicability of the proposed matching methodology.     

Zones of required investigation for earthquake-related hazards in Jerusalem

Jerusalem was hit by earthquakes several times in its history, in the course of which none of the holy sites of the three main faiths of the western world escaped damage. Intensities of the last M_L 6.2, July 11, 1927 Dead Sea earthquake, reached MSK VIII in the Old City of Jerusalem and the surrounding villages. As future strong earthquakes are inevitable, the need for the evaluation of earthquake-related hazards is obvious. Only general geotechnical properties of the section exposed in the mountainous area of Jerusalem are available; therefore, the hazard assessment was conducted from a geological perspective. The hazards identified in this study are: (1) amplification of seismic acceleration due to soft rock and soil conditions; (2) amplification due to mountainous topography; (3) dynamic instability of natural slopes; and (4) potential failure of slopes that have undergone engineering development and were weakened due to damaging, steepening, overloading, and wetting beyond their natural state. We formulated relative grades of vulnerability for each of the hazards and delineated the zones that require further specific investigation. For practical use we constructed a summary map that combines the different hazard categories. Looking at the summary map, the ground at the central N–S axis zone across Jerusalem is the least vulnerable. The bedrock there is mostly hard carbonate, the topography is mild, and thus only the alluvial cover, if thicker than 3 m, should be considered sensitive. Yet although the natural hazard in this area is limited, the risk should not be underrated. Much of the city lies there, including buildings constructed before antiseismic codes were regulated, and traditional engineering practice should not be taken for granted as antiseismic proof either. Eastwards, the shear wave velocity (Vs) contrast between the hard and soft rocks as well as the notable topography in places, impose the potential for amplification. Slopes, either naturally or artificially cutting into the soft chalk, may expose the area to dynamic instability; thus, the ongoing extensive development of the city in this direction should certainly take into account all of this. West of the central axis, the potential of failure of both steep natural and urbanized slopes appears. Being a plausible direction for future urban expansion, these areas specifically call for careful environmental and engineering planning. For engineering purposes, however, a specific site investigation is still necessary. Nevertheless, the summary map established in this study sets up for Jerusalem, for the first time, a practical tool for environmental and municipal planning, emergency response planning, and civil protection.     

Evolution of isotopic compositions in groundwater of the area between the Gulf of Oman and the Arabian Gulf

The stable isotopes of oxygen and hydrogen have been implemented to assess the recharge mechanisms in an area in the UAE bounded to the northwestern part of the Gulf of Oman and the southeastern part of the Arabian Gulf. The conversion of stable isotopes to deuterium excess was utilized as a supportive tool to understand the process of groundwater recharge. The concluding results of this study showed that the origin of moisture is the Mediterranean Sea. The precipitation is the main source of recharge, in which the precipitation having undergone evaporation before recharge occurs. The comparison between regression line for data collected in 1996 and regression line for samples collected in 2006 suggests that the precipitation water which recharged the groundwater, was diluted with groundwater and this dilution is observed from decreasing of the deuterium excess of collected groundwater samples with increasing isotopes of oxygen. The dilution of groundwater with the recharge water suggests modern-day recharge as it is seen from high deuterium excess that exceeded the deuterium excess of LMWL and was close to MMWL.     

Dimorphism in Placenticeras mintoi from the Upper Cretaceous Bagh Beds, central India

The Upper Cretaceous Bagh Beds yield many biota of which ammonoids are particularly well known. Previously Bagh ammonoids were grouped into many genera and species within several families. The present study, however, shows that failure to recognize dimorphism and a wide range of interspecific variation within the single genus Placenticeras perhaps results in taxonomic oversplitting. Specific dimorphism in P. mintoi has been established.     

Analysis of drivers governing temporal salinity and temperature variations in groundwater discharge from Altug Submarine Karst Cave (Kas-Turkey)

Salinity and temperature variations in groundwater discharge from the Altug submarine karst cave have been observed at 28 m below sea level for every 10 min between November 2004 and August 2005 to determine the drivers that govern the salinization. Comparisons between temporal trends of salinity and temperature with those of precipitation, air pressure, sea level and wind velocity revealed an apparent dominance of precipitation regime on the salinity and temperature variations. Spectral analyses applied to observations showed that the air pressure and sea level oscillations are affected by sun and moon tides which do not have an appreciable impact on the salinity and temperature variations. Annual rate of salinization in Altug cave seems inversely related to the inland groundwater head so that the maximum and minimum fresh water contributions occur at mid-spring and late-summer, respectively.     

Response of groundwater chemistry to water deliveries in the lower reaches of Tarim River,Northwest China

In this paper, we analysed the monitored data from nine groundwater-monitoring transects in the lower reaches of Tarim River during the five times of stream water deliveries to the river transect where the stream flow ceased. The results showed that the groundwater depth in the lower reaches of Tarim River rose from −9.30 m before the conveyances to −8.17 and −6.50 m after the first and second conveyances, −5.81 and −6.00 m after the third and fourth the conveyance, and −4.73 m after the fifth. The horizontal extent of groundwater recharge was gradually enlarged along both sides of the channel of conveyance, i.e., from 250 m in width after the first conveyance to 1,050 m away from the channel after the fourth delivery. With the rising groundwater level, the concentrations of major anions Cl⁻, SO₄²⁻ and cations Ca²⁺, Mg²⁺, Na⁺, as well as total dissolved solids (TDS) in groundwater underwent a significant change. The spatial variations in groundwater chemistry indicated that the groundwater chemistry at the transect near Daxihaizi Reservoir changed earlier than that farther from it. In the same transect, the chemical variations were earlier in the monitoring well close to watercourse than that farther away from the stream. In general, the concentration of the major ions and TDS at each monitoring well increased remarkably when the water delivery started, and decreased with the continued water delivery, and then increased once again at the end of the study period. Hence, the whole study period may be divided into three stages: the initial stage, the intermediate stage and the later stage. According to the three stages of groundwater chemistry reaction to water delivery and the relationships between groundwater chemical properties and groundwater depths, we educe that under the situation of water delivery, the optimum groundwater depth in the lower reaches of the Tarim River should be −5 m.     

A probabilistic tsunami hazard assessment for the Makran subduction zone at the northwestern Indian Ocean

A probabilistic tsunami hazard assessment is performed for the Makran subduction zone (MSZ) at the northwestern Indian Ocean employing a combination of probability evaluation of offshore earthquake occurrence and numerical modeling of resulting tsunamis. In our method, we extend the Kijko and Sellevoll’s (1992) probabilistic analysis from earthquakes to tsunamis. The results suggest that the southern coasts of Iran and Pakistan, as well as Muscat, Oman are the most vulnerable areas among those studied. The probability of having tsunami waves exceeding 5 m over a 50-year period in these coasts is estimated as 17.5%. For moderate tsunamis, this probability is estimated as high as 45%. We recommend the application of this method as a fresh approach for doing probabilistic hazard assessment for tsunamis. Finally, we emphasize that given the lack of sufficient information on the mechanism of large earthquake generation in the MSZ, and inadequate data on Makran’s paleo and historical earthquakes, this study can be regarded as the first generation of PTHA for this region and more studies should be done in the future.     

Comments to the article by Verner et al.: Magmatic history and geophysical signature of a post-collisional intrusive center

Verner and co-authors (Int J Earth Sci (2009) 98:517–532) published geological and structural model of evolution and emplacement of the Plöckenstein pluton in the border area of Austria, Germany and Czech Republic. They used data of other authors, giving no reference as to their source, for interpretations without any discussion of the already published results.