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71.
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73.
Natural Hazards - A network of 25 lightning detection sensors (LDS) has been established by the National Remote Sensing Centre (NRSC), the Indian Space Research Organization (ISRO). At present,... 相似文献
74.
A sudden disturbance in water level was recorded by hydrographs monitoring wells in the coastal city Dammam, Saudi Arabia
on December 26, 2004. The water level was being recorded from the shallow (1–3 M deep) coastal aquifer at that time. In two
wells, this disturbance was observed ~12 h after the Sumatra earthquake/tsunami event of December 26, 2004. The timing of
this event is synchronous in two wells near the coast, but an inland well away from the coast line did not show any such disturbance.
It is hypothesized that this disturbance, we call it the “shock event”, is resulted by sudden impact of tsunamis traveling
in the Arabian Gulf from southeast toward northwest. As the tsunamis propagated, they suddenly impacted the coastal shallow
groundwater aquifer resulting in the “shock event”. 相似文献
75.
The Koyna River basin in India drew the attention of geoscientists after an earthquake (magnitude 7) in 1967. Since then,
detailed geological, tectonic, and seismic investigations of this river basin have been carried out by several workers. However,
very little study has been done on its hydrogeological framework. The present work aims at filling this gap. Basalts, laterites,
alluvium, soils, and talus deposits form shallow unconfined aquifers, with transmissivity of 27–135 m2/d and a regional specific yield of 0.012. In shallow basaltic aquifers, the lower part of the highly weathered and highly
jointed horizon above, and the poorly weathered and highly jointed horizon below, form the most potential zone for groundwater
occurrence. Well yields in the deeper basaltic aquifers are directly related to the occurrence of lineaments, whereas at a
shallower level they are related to geomorphic features. Spring discharges are highly dependent on their source aquifers and
areas of recharge. They have a mean winter discharge of 46 m3/d and a summer discharge of 28 m3/d.
Chemically, groundwaters are dominated by alkaline earths (Ca2+, Mg2+) and weak acids (HCO3
–, CO3
–); they are calcium-bicarbonate type (53%) and calcium-magnesium-bicarbonate type (27%) at shallower levels; and calcium-magnesium-bicarbonate
type (29%), sodium-bicarbonate type (24%), calcium-bicarbonate type (19%), and calcium-magnesium-sodium-bicarbonate type (19%)
in deeper aquifers. The Koyna River basin is characterized by both scarcity and abundance of groundwater. In the water-scarce
areas in the dissected plateaus, artificial recharge of aquifers through construction of several recharge structures at suitable
locations is highly recommended. In the water-abundant areas in the central valley, on the other hand, expanded consumptive
use of water resources is encouraged.
Electronic Publication 相似文献
76.
Dilip G. Durbude B. K. Purandara Arun Sharma 《Journal of the Indian Society of Remote Sensing》2001,29(1-2):47-58
An accurate assessment of run-off through aerial rainfall is a basic concept in most of the rainfall-runoff models, particularly conceptual models which emphasis a complete water balance. The run-off measurements by gauging can only be regarded as an index of rainfall and restrict our ability to successfully model the rainfall-runoff process. To overcome some of these problems, remote sensing satellite data are of immense use, particularly in mountainous and desert areas. Therefore in the present study, a typical watershed from a drought hit Banswara district of Rajasthan has been analysed using IRS-1B-LISS II satellite imagery for estimating the run-off potential under different geomorphic set-up. The run-off potential was estimated using SCS method based on the satellite data in conjunction with ground truth information collected during field visit. The results indicated that the soil and water conservation measures in the watershed would improve the existing water potential and storage capacity of the study area. Based on the study eight check dams and five lift irrigation schemes are proposed. 相似文献
77.
Linear relationship between dipole and Schlumberger sounding resistivities leads to the use of digital filters to transform the former to the latter. This transformation is of importance from the viewpoint that Schlumberger interpretational techniques and know-how could then be applied to the pseudo-Schlumberger field curve. Filters for this transformation are presented for the radial, perpendicular, and parallel (30°) dipole method. The characteristics of these filters are similar to the ones for transforming dipole data to the kernel and are favourable in that they do not amplify noise. A sampling interval of (In 10) /6 has been used in determining the filter yielding good accuracy. Like previous filters the present one is handy and fast in operation. 相似文献
78.
The combined observation of first and later arrivals in shallow seismic refraction surveys, particularly on hard rock terrains, is discussed. Details of experimental weathered-zone investigations by the correlation refraction method in a granite terrain (i.e. field procedure, seismograms obtained, plotting of the data, and identification of the waves are presented). Complete travel time data and interpreted subsurface sections of a few test refraction surveys are included. In one instance the interpreted results of normal and converted refracted wave data have been tested by drilling at three points along a 220 m long profile. 相似文献
79.
P. S. Arun R. Jana M. S. Nathawat 《Journal of the Indian Society of Remote Sensing》2005,33(2):189-201
Efficient micro-watershed management needs characterization of it to optimize natural resources, which is especially important
in drought prone areas. In the present study micro-watersheds of Gandheshwari tributary in Chotta-Nagpur Plateau are characterized
based on physiographic properties towards agricultural potentiality. An algorithm interpolating elevation values using an
empirical formula is proposed to obtain an improved Digital Elevation Model (DEM). IRS LISS-Ill Satellite data is used to
acquire important parameters like landuse/ landcover and drainage. Image processing techniques like edge enhancement, edge
detection, and principal components analysis are used for improving lineament detection. For characterization of watershed
landform analysis using physiographic parameters is done in Geographic Information System (GIS). Detailed drainage network
obtained from satellite image, the improved DEM and other GIS layers of land based information are used to delineate micro-watersheds.
The Agricultural 1-lydrologic Response Units (AHRU) targeting agricultural use of the land are derived by overlaying the delineated
parameters and are grouped into thirty response units based on their agricultural potential. Micro-watersheds are characterized
based on the dominant Al-IRU giving spatial information about agricultural suitability, emphasizing availability and scarcity
of water so that respective water conservation practices can be improved to use the potential AHRU. 相似文献
80.
Arun V. Thampan & Bhaskar Datta 《Monthly notices of the Royal Astronomical Society》1998,297(2):570-578
We calculate the disc and boundary layer luminosities for accreting rapidly rotating neutron stars with low magnetic fields in a fully general relativistic manner. Rotation increases the disc luminosity and decreases the boundary layer luminosity. A rapid rotation of the neutron star substantially modifies these quantities as compared with the static limit. For a neutron star rotating close to the centrifugal mass shed limit, the total luminosity has contribution only from the extended disc. For such maximal rotation rates, we find that well before the maximum stable gravitational mass configuration is reached, there exists a limiting central density, for which particles in the innermost stable orbit will be more tightly bound than those at the surface of the neutron star. We also calculate the angular velocity profiles of particles in Keplerian orbits around the rapidly rotating neutron star. The results are illustrated for a representative set of equation of state models of neutron star matter. 相似文献