A search for correlation between seismicity and radon anomaly in hot springs

Measurements of radon contents of the exholved gas emanating from several hot water springs along the Western Coast of India are reported here. Concentration of radon in gas phase of individual springs varied in general, directly with the surface temperature of the water emerging from the respective springs, and showed little variation with time. Radon measurements were carried out continuously for about two years at two hot springs located at Ganeshpuri and Sathivali in the coastal area of Northern Maharashtra. The distant tremors did not cause any variation in the radon content. There was no marked local seismic activity during the period of observations, and the levels of radon stayed essentially constant. The measurements were also carried out at a hot spring in Assam, for about 8 months. These also did not show any significant variation; this period too lacked any marked local seismicity.     

Strontium isotope geochemistry of alpine tectonite lherzolites: Data compatible with a mantle origin

Constituent minerals from three alpine lherzolites (Beni Bouchera, Morocco; Lanzo, Italy; and Ronda, Spain) and a clinopyroxene from the Othris complex, Greece, reveal the following range in Sr isotopic composition: clinopyroxenes, 0.70228–0.70370; orthopyroxenes, 0.70265–0.70429; and olivines, 0.70290–0.70831. Collectively the data: (1) indicate that whole-rock lherzolites (weighted recalculations of ⁸⁷Sr/⁸⁶Sr= 0.7025–0.7028) have isotopic compositions which attest to a simple mantle origin and not the complex models proposed to date; (2) are incompatible with the published range for alpine peridotites 0.7063–0.7290; (3) reveal either similar or different isotopic compositions for coexisting minerals, the latter possibly being the result of Rb mobility and introduction of radiogenic Sr into the peridotite system; and (4) indicate the past existence of liquids with “alkalic” affinities within the lherzolite framework. The lherzolites are therefore believed to be residual, having experienced a small degree of partial melting.     

Aseismic strength of kolkewadi dam

Kolkewadi Dam, a masonry gravity dam in India, is under construction at a'site which was considered to be non-seismic at the time of planning and design. Subsequently, some major and minor earthquake shocks have occurred in the area. In view of the earthquake activity in the region, it was necessary to estimate the seismic resistance of the dam. A dynamic analysis of the two highest monoliths of the dam has been carried out, based on the probable ground motion expected at the site, including a simplified analysis, treating the dam as a cantilever beam and a detailed analysis considering two-dimensional behaviour by the finite element method. It is concluded that the dam will be able to safely withstand the severest shock that has occurred in the region. The behaviour of models of one monolith has also been studied experimentally using a shake table. The experimental behaviour of the models compares favourably with the behaviour obtained theoretically, indicating the applicability of the theoretical method of analysis.     

Magnetic study of a metabasic dyke in Dhaiya,Dhanbad (Bihar)

Summary A metabasic dyke of pre-Cambrian age passing through Dhaiya village in Dhanbad, consists of metanorite, metadolerite and epidiorite. A magnetic study of this dyke has been undertaken. 14 magnetic traverses were taken with Schmidt vertical force variometer. Direction and intensity of N.R.M. have been determined for 15 oriented samples, with an astatic magnetometer. Magnetic susceptibility of 36 samples has been determined. Microscopic study (thin and polished sections) of samples has been done. The intensity of N.R.M. is upto 11.830×10^–3 c.g.s. units susceptibility varies from 53×10^–6 to 750×10^–6 c.g.s. units and the Koenigsberger ratio from 3.3 to 236.6. The magnetic profiles are interpreted taking into account both remanence and susceptibility. In case of metanorite and metadolerite, more than 80% of the anomaly is caused by remanence. Negative anomalies in some cases is due to negative inclination of remanent magnetization. Very low anomalies (less than 50 gammas) over epidiorite are due to loss of magnetism (both remanent and induced) of these rocks due to felspathization. A new mechanism has been proposed to account for the scatter in magnetic directions for metamorphosed igneous rocks. The rotation, during metamorphism, of magnetic grains (magnetite, ilmenite etc.) enclosed in the lenticular rock-forming minerals causes deviation of the magnetic vector from its original position. Two more causes have been suggested here to explain the variation of intensity of N.R.M. of metabasic rocks: (i) Ilmenite exsolved from titaniferous augite partly contributes to the N.R.M. (ii) magnetite dust injected into felspars by solutions during metamorphism, causing cloudiness in felspars, partly contributes to the N.R.M. The wide scatter in remanent magnetic direction in these rocks is due to the effects of metamorphism. The magnetic directions fall under two groups: one with positive inclination and the other with negative inclination; both the groups being, in general, magnetized normally in the horizontal direction. This indicates normal magnetization in northern and southern hemispheres respectively. This probably means that the place was in the northern and southern hemispheres at the time of original emplacement of the dolerite magma and of metamorphism respectively, the metamorphism, not affecting all the rocks uniformly.     

Satellite-based assessment of physiographic disposition to health problems in kasargod district,Kerala, India

Photo interpretation and digital classification of IRS LISS -III sensor data have been carried out for a few villages affected by abnormal health problems in the Kasargod district of Kerala State. Physical location of the affected villages in relation to the agricultural lands use, watershed characteristics and the extent of cashewnut plantations are studied. It was found that the villages affected by the health problems are located in the microwatersheds that have steep slopes, nearly circular in shape, high runoff potential. The first order streams within these micro-watersheds are originating from the cashewnut plantations that are sprayed with a toxicant called Endosulfan. The study recommends to stop aerial spraying of any toxicant on the cash crops of these watersheds.     

Total information content as an index of soil moisture

Accurate estimation of soil moisture through remote sensing technique has been a challenge till date. In optical and thermal remote sensing, there is no index developed to detect the changes in soil moisture levels. In microwave region, soil roughness and other target parameters equally affect the technique for soil moisture estimation. Therefore, a computational technique in C language based on Shannon’s Information Theory (Shannon, 1948) has been developed to calculate total information content from multispectral radiometer data. The total information content is a compressed single value, which quantifies the information content of soil spectral reflectance in the electromagnetic spectrum range (400–1100 nm) under study. This technique was tested over a wide range of soil moisture levels. The study revealed that as compared to other techniques total information content index is very sensitive to change in moisture content of soil. This technique could not only quantify the soil moisture content in optical and near infra red region, but also led to a simplified one dimensional separability and clustering analysis.     

Geomorphological study of sundarban deltaic estuary

Study of landforms in Sundarbans deltaic estuary is necessary in regular basis due to its importance and impact on ecology, climate and economy. Remote sensing has proved as an important tool to study this. Multi-temporal satellite data helps to delineate the various geomorphic classes in different time domain and also provide inputs to study the coastal erosion and accretion. Finer spatial and better temporal resolution will be an added adventure for this kind of study.     

Soil resource appraisal towards land use planning using satellite remote sensing and gis a case study in patloinala micro-watershed, district puruliya, west bengal

Visual interpretation of IRS ID LISS-III fused with PAN data (1:12,500 scale) ofPatloinala micro-watershed of Puruliya district, West Bengal was carried out for delineating the physiographic units based on the variations in image characteristics. The major physiographic units identified were upland(Tanr), medium land(Baid), and low land(Bahal andKanali). The satellite remote sensing data coupled with ground truth were translated in terms of soils using composite interpretation map as base. The abstraction level attained was phases of soil series based on Soil Taxonomy. On the basis of physiographic variation and soil or soil site characteristics such as texture, depth, slope, erosion etc. the problem areas were identified and land use plan has been suggested for the overall development of the micro-watershed.     

HE 1127–1304: the largest radio quasar

By considering the propagation of low-amplitude magnetohydrodynamic waves in partially ionized plasmas, it is shown that the ion-neutral drift (ambipolar diffusion) induced by the waves can have specific effects on the molecular chemistry of cold material. The chemistry occurring in gas swept by Alfvén waves is described and it is shown that this leads to spatial variations in the deuterium fractionation ratios of, for example, HCO⁺ and N₂H⁺, on spatial scales of a few hundredths of a parsec, depending upon the fractional ionization of the ambient medium. The possibility of detecting interstellar Alfvén waves by molecular spectroscopy and their effect of producing small-scale chemical abundance gradients in molecular clouds are briefly discussed.     

Hydrogeomorphological studies by remote sensing application in niva river basin, chittoor district, andhra pradesh

To evaluate the hydrogeomorphological conditions of Niva river basin Chittoor district, Andhra Pradesh, geological, hydrogeological and geomorphological studies were carried out. through visual interpretation of Landsat 5, FCC with adequate ground truth. The study shows that the Niva river basin is occupied by granites and gneisses of Archaean age with intrusive bodies of dolerites. The recent alluvium deposits are present along the stream courses. The study area is traversed by various directional fractures/lineaments and most of them are NESW, ENE-WSW and EW directions. Groundwater potential of geomorphological units viz. Denudational hill, Residual hill, Pediment, Pediplain and Valley fill is discussed.