023453   Chakrabarty K K;Nath A K;Sengupta S (NO, Regional Meteorological Centre, Alipore, Kolkata) : Nor's wester over West Bengal and comfortability. Mausam 2007, 58(2), 177-88.

During the pre-monsoon months when the climate over Kolkata is very sultry and uncomfortable, people generally desire the onset of nor'wester for some temporary relief although it results into destruction. The nor'wester makes the weather comfortable after its occurrence and remains comfortable for 10 to 12 hours and some time even for a day. The study is made taking six years data over Kolkata, both Alipore and Dum Dum. It is seen that except early morning of March the remaining period of pre-monsoon season is found to be uncomfortable climatologically. In the study there were 91 occasions of squalls and it is found that most of the squalls occurred during the month of April and May and on most of the occasions nor'wester made the weather comfortable for a large part of the day in the month of April. By the end of May nor'wester activity also brought relief but not to that extent as in March and April to the people of Kolkata and neighborhood.

3 illus, 6 tables, 2 ref

023452   Bhide U V;Bawiskar S M;Mujumdar V R;Puranik P V;Ghankear S P;Kulkarni A A (NO, Indian Institute of Tropical Meteoroloy, Pashan, Pune-411 008, Email: bhide@tropet.res.in) : Secondary heat sources over India during southwest monsoon 2002. Mausam 2007, 58(2), 213-28.

Southwest monsoon of 2002 has three unusual features viz., (i) delay in advance over western most parts of India by one month, (ii) absence of depressions/storms over Bay of Bengal and Arabian Sea and (iii) -51% departure of all India rainfall in July. These features of intra-seasonal variability have been studied. Apparent heat source (Q₁) and apparent moisture sink (Q₂) over Indian region have been estimated using daily NCEP-reanalysis data, for June - September 2002 to study the intra-seasonal variations of the secondary heat sources in relation to observed intra-seasonal variations of circulation and rainfall over India. The intensities of vertically integrated heat source (Q₁) and moisture sink (Q₂) are found to coincide with the excess rainfall zone over India in June 2002, whereas the intensities of (Q₁)> and (Q₂) over central parts of the country in July 2002 are not comparable. This indicates absence of convective rainfall and increased sensible heating over India in July. The x-t diagram of heating and drying rates at 500 hPa along 22.5° N shows large positive heating and drying rates of the order of 16°C per day over the western trough region around 26 June. Following this event, low positive or negative values are observed over central India in July. The y-t diagram of vertical velocity at 500 hPa shows strong subsidence near the foot hills of Himalayas during the season. This has affected the formation of depressions cr storms over Bay of Bengal and Arabian Sea. Adiabatic and diabetic heating as well as drying in the troposphere has led to the break-like situation over India in July 2002 and weaker monsoon circulation during August and September. The analysis has brought out the impact of northern hemispheric mid-latitude circulation on intra-seasonal variability of southwest monsoon 2002 more clearly.

10 illus, 21 ref

023451   Bhattacharya A K;Ghosh M;Fulmari M (NO, , Bhu-vijnan Bhawan, Karunamoyee, Salt Lake, Kolkata-700 091) : Morphology and petrography of pillow volcanics within Deccan traps of Chhindwara and Kundam area of Central India - some clues on eruptive environment. Indian Miner 2007, 61(1-2), 17-24.

Pillow structures within Deccan Trap of Madhya Pradesh occur widely distributed around Chhindwara and Jabalpur districts along the Narmada-Tapi lineaments. The individual pillows have shapes like, bun, balloon, tongue, ball and boat, etc. The size of individual pillow ranges from less than a metre to about 2 m along longer axis. Amount of pillow breccia / hyaloclastites associated with pillows varies from 5% to 90% by volume. In general the chilled crust of individual pillow is more than 4-cm thick. Unaltered pillows at many places are characterised by a tubular hollow in the central part, which at many places is filled up by secondary silica. Mineralogy of the rock is defined by a few phenocrysts of plagioclase laths with distinctive swallowtail twinning, fine irregular grains of clinopyroxene and abundant microlites of plagioclase set on a hyaline base. The overall study indicates that pillows in the area are formed from drastically quenched basalt bodies under glacial to fluvio-glacial environment.

7 illus, 22 ref

023450   Bandyopadhyay D K;Ghosh S;Mondol A;Das D K (Geological Survey of India Central Chemical Laboratory, 15 A & B Kyd Street, Kolkata-700 016) : Role of rare earth elements as provenance indicator in coal seams: a case study from IB-river coalfield, Orissa. Indian Miner 2006, 60(3-4), 171-80.

Abundance of rare-earth elements in the ash fractions of two coal seams viz., Lajkuria and Rampur belonging to Barakar Formation of Ib-river Coalfield in Orissa have been studied. While Lajkuria seam was studied for REE distribution in space and time on the basis of 18 subsurface samples collected from three depth zones viz., 0 - 30 m, 90 -170 m and 280 - 305 m and from three wide-apart boreholes, REE- abundances of Rampur seam was utilised to compare with those of Lajkuria seam intersected in the same borehole. It is observed that, in general, the ash content at different levels of Lajkuria seam progressively increases with depth without any significant relationship to REE abundances. Significant features noted from both the Lajkuria and Rampur seams are the U- shaped LREE- pattern coupled with mixed type Sm- and Eu-anomalies (+ ve, zero and - ve ) and depleted HREE pattern. These REE signatures imply that the inorganic components in the ash were derived from a bimodal provenance comprising primary basement of garnet-zircon-depleted but clinopyroxene-amphibole-enriched gneiss and secondary provenance of feldspathic to non-feldspathic shale. Ce-depletion is attributed to marine incursions in an overall continental environment. Maximum extent of recycling and disintegration of continental shale during the geological period from Archaean to Permo-Carboniferous is reflected in wide fluctuation of REE abundances (0.4 - 20 times NASC) of Lajkuria seam.

7 illus, 5 tables, 9 ref

023449   Acharyya A;Dasgupta S (Geological Survey of India 27 Jawaharlal Nehru Road, , Kolkata-700 016, Email: anshuman_cal@yahoo.com) : Tectonic deformation due to 26 december 2004 earthquake-revisited in Andaman. Indian Miner 2006, 60(3-4), 119-36.

Tectonic deformation produced by the fault rupture of the great Sumatra-Andaman earthquake of 26 December 2004 shows zones of uplift and subsidence separated by neutral line (locale of zero vertical displacement) in the Andaman Islands. The ground deformation pattern estimated during May 2005 has been re-constrained on the basis of additional data collected in January 2006. A maximum uplift of 1.5 m to the west of the neutral line is recorded at the west coast of North Andaman near Temple Sound while the westernmost landmass of Middle Andaman exhibits uplift of 1.42 m and 1.3 m at Interview Island and South Reef Island respectively. Areas of subsidence east of the neutral line register 0.70 m and 1.20 m in Chidiatapu and Chatham areas of South Andaman respectively. In either side of the neutral line, signatures of post-seismic adjustment are witnessed at places. As a consequence of post-seismic incremental diurnal rise of tidal water in an otherwise domain of emergence, residual uplift of 0.50 m is estimated in Kalighat Jetty (North Andaman) in comparison to +0.95 m estimated in May 2005. Likewise, diurnal fall in tide level is observed in the submergence domain at Chidiatapu as a likely fallout of post-seismic relaxation. Inferred maximum slip at the trench in North Andaman (<126>5.3 m) is comparable with that in South Andaman (<126>4.2 m), both being much less in comparison to 10-15m estimated slip in Sumatra generating catastrophic tsunami waves. Two simple slip dislocation cartoons illustrate 160 km of locked interface of the rupture in North Andaman while in South Andaman it is 100 km from the trench boundary. Geometry of Benioff zone in South Andaman demonstrates marginally higher dip with wider accretionary prism than that in North Andaman.

20 illus, 1 table, 29 ref

022455   Wadhwa R S;Rani C K;Chaudhari M S; Mukhopadhyay R;Ghosh N (Central Water and Power Research Station, Khadakwasla, Pune-411 024, Email: wadhwa_rs@cwprs.gov.in) : Chirp sonar survey for development of Jawaharlal Nehru port. J Indian Geophys Union 2007, 11(4), 181-7.

Underwater geoengineering survey deploying dual frequency echo-sounder and chirp sonar system (pulsed frequency modulation signal 500 Hz to 8 KHz) from a precisely positioned vessel was carried out along seven traverses at Jawaharlal Nehru Port near Mumbai where the existing harbour is to be dredged to -16.5m depth near the berths and to -12.5m depth elsewhere to accommodate larger size vessels. The lengths of the traverses varied between 175m and 415m. Isopach map of the sediment thickness drawn from the results of the chirp sonar system revealed that the sediment thickness from sea-floor varies from Om to llm. Rock at places was inferred to be exposed to sea-floor. The boundary of the rock outcropping patch was precisely deciphered and marked on the site plan. The quantity of rock to be dredged was worked out to be 1.95 Lakh cubic metres. The basalt rock for dredging will either require rock cutter dredgers or blasting. The rock levels evaluated using chirp sonar system matched remarkably well with rock levels inferred in few boreholes drilled in 1980. At some locations the superficial material with physical properties different from that of sea-floor was detected and was interpreted to be dumped material. The maximum lateral extent and thickness of the dumped material was 100m and 5m respectively.

5 illus, 7 ref

022454   Tuljapurkar V B (NO, , Shalmalee, Shivaji Nagar, MIRAJ-416 410) : Monsoons in bygone era. Trans Inst Indian Geogr 2007, 29(2), 153-61.

The seers of vedic age, seafarers and intrepid explorers, traders, civil servants, poets, historians, geographers and many others studied, interpreted and wrote about the rainy season in Indian sub-continent. Since the vedic age till today we are seeking answers to questions like - Has it been seasonal in the past as it is now? Has it been adequate all the time? Were there periods of aridity or heavy rains spanning over extended time? Have the strings of rain left any records of their frequency and quantum? When did the inhabitants of India realize its importance in their life? Attempts to find answers to these and similar questions.

20 ref

022453   Muthuchami A;Dhanavanthan P (Regional Meteorological Centre, Chennai Statistics Dep, Pondicherry Univ, Pundhucherry) : Probable storm motion in the Bay of Bengal in April and May. J Indian Geophys Union 2007, 11(4), 209-15.

Using data of cyclonic storm tracks for the period 1891 to 2000 over Bay ol Bengal an attempt is made to find out the probable storm track and probable latitude of crossing of storms in pre-monsoon months of April and May. It has been found that in pre monsoon season the predominant direction of motion of storm is north-northeast in April and north in the case of May. In the month of April initial formation of storm mostly determines the location of crossing whereas in the case of May such prediction is not reliable. The relation between longitudes and latitudes of storm positions is expressed in terms different mathematical expressions during April and May. In the month of April whether the storm is in the easterly or in the westerly regime, the storm track is mostly parabolic. But in the case of May when the storm is wholly under the control of westerly regime, the tracks are in the form of logarithmic curves whereas when they are in easterly regime and then caught under westerly regime they are parabolic.

3 illus, 13 ref

022452   Mishra A P;Rai S;Pandey A C (Central Water Commission, Dibrugarh, Assam-786 003, Email: rediffmail.com,anshu_ms@yahoo.com) : An estimation of heat flux and its variability in the Southern Indian Ocean (SIO) using Ocean general circulation model. J Indian Geophys Union 2007, 11(4), 217-28.

Evaluated annual mean and seasonal means net heat flux at the ocean surface for the period 1975-1998 from an ocean model results for Southern Indian Ocean (SIO) having spatial coverage 0.25°N-74.25°S & 15.75°E-120.75°E. It has been found that model annual mean and seasonal means net heat flux fields agree moderately with Southampton Oceanography Center (SOC) climatological heat fluxes and there are spatial inconsistencies in computation against a good agreement in-between model and SOC data sets in the region of interest. These discrepancies may be due to deficiency with model physics or sampling related bias in SOC data sets. Further, nature of variability of surface heat flux field in SIO was studied using Empirical Orthogonal Functions (EOF) techniques. Interannual variability represented in the first EOF of surface heat flux anomaly shows a strong trend in the Antarctic Circumpolar Current (ACC) region and significance variability around ten years.

6 illus, 21 ref

022451   Mahapatra M;Mahapatra S (Geology Dep, Durgapur Government College, Durgapur-713 214, Email: mahasweta_mahapatra@redffmail.com) : A new approach to seismic diffraction tomography technique and its significance in ore-body prospecting. J Indian Geophys Union 2007, 11(4), 189-96.

Diffraction, once considered noise rather than signal in seismic tomography, has recently been successfully used in ore-body prospecting, particularly in delineating smaller objects which otherwise cannot be properly investigated by ray tomography methods. Most prevalent seismic diffraction tomography techniques use Born's approximation of weak scattering instead of considering total wave field. In the present study, using total scattered wave field, at first, the forward modeling for objects of different geometrical shapes and sizes, both separately and in combination is done and then very fast simulated annealing is employed for inverse modeling. Subsequently, annealing parameters are used to determine the model parameters such as size, contrast and distance of the object from measuring plane. This gives fairly good estimate for model parameters within acceptable error limit. This procedure of seismic diffraction tomography technique can potentially be used for investigating ore-body of smaller dimension having not only weak but also strong scattering properties.

5 illus, 4 tables, 13 ref

022450   Kushwaha R A S;Nandini Devi Y;Okendro M;Goel O P (Earth Science Dep, Manipur Univ, Manipur, Email: rs_kushwaha@rediffmail.com) : Landform and landuse analysis of Thongjaorok basin, Manipur. Trans Inst Indian Geogr 2007, 29(2), 195-201.

Based on the visual interpretations of Topographic maps, LANDSAT Imagery and field checks different types of landforms have been identified in the area, which include: structural hills, denudational hills, valleys, flood plains and associated features. On the basis of magnitude these landforms are divided broadly into two categories, i. e., major and minor landforms that are utilized by man and nature for different purposes. On the basis of the data generated from the visual interpretation of Topographic maps (1970) and IRS-ID-LISS-III Geo-coded FCC (2000) on 1:50,000 scale and field-checks, nine different categories of land-use / land-cover are identified in the Thongjaorok River basin. Between 1970 and 2000 there have been drastic changes in the land use/land cover patterns in the area. It is intriguing to note that there is increase in the forest area, settlement and water bodies while decrease in the open scrub areas. Increase in the forest area is mainly due to the social forestry taken up by the Forest Department, Govt. of Manipur.

3 illus, 2 tables, 15 ref

022449   Kushwah V;Singh V;Singh B (Physics Dep, R.B.S. College, Bichpuri, Agra-283 105, Email: birbal@sancharnet.in,bbsagra@yahoo.co.in) : Ultra low frequency (ULF) amplitude anomalies associated with the recent Pakistan earthquake of 8 October, 2005. J Indian Geophys Union 2007, 11(4), 197-207.

Employing a system of 3- component search coil magnetometer (f = 0.01 -30 Hz), ULF magnetic field emissions associated with earthquakes have been monitored at Agra since September 2002. The bulk of the data shows that normally the amplitudes of the three components (Bx, By, Bz oriented toward north-south, east-west, and vertical directions respectively) are low between 0.01 and 0.3 nT. However, By and Bz components are found to be enhanced considerably in the range of 0.3 - 2 nT ( Bx being the smallest ) occasionally. Such enhancements are correlated mostly to occurrence of earthquakes where enhancements in By and Bz correspond to earthquakes mostly in North-East (or North- South) and Northwest direction from Agra respectively. Recently, one such correlation has been found between the enhancements in Bz components and large magnitude earthquake (M = 7.7) that occurred in Muzaffarabad (Pakistan) about 900 1cm northwest from Agra on 8 October, 2005. We have examined the amplitude enhancements in the light of solar flares and magnetic storms during the whole month of October, 2005 and found a negative correlation with these events. An interesting result obtained was that the enhancements occurred as precursors, first about 10 days before between 27 and 30 September, and then 3 days before on 05 October, 2005. The precursory characteristics of the signal is confirmed by a statistical analysis of the data for a period of fifteen days before and fifteen days after from 17 Sept., 2005- 29 Oct., 2005 by employing mean (m) and mean around standard deviation (m±2a) approach. The enhancements in the intensity of the precursory signals are also observed from a wavelet analysis of the data. The frequency -time spectrogram and power spectrum analysis of the data show the enhancements around 2 Hz and 7-8 Hz and polarization analysis of the data shows that the signals propagated from below.

8 illus, 1 table, 28 ref

022448   Kaveli M;Gore S D;Pawar N J;Sukhtankar R K (Physics Dep, Hormozgan Univ, Bandarabbas, Iran) : Establishing a relationship between the frequency and magnitude of earthquakes for some parts of Hormozgan province, southern Iran. Acta Cienc Indica-Phys 2008, 52(2), 35-50.

Hormozgan province is located in southern Iran (52° : 41'-59° : 15' E, 25° : 24' - 29° N). In this region, over 1086 earthquakes have been recorded between 1930 and 2006. The locations of these events belong to some active faults and seismically active tectonic zones in this region. The famous faults in this area are Khorgo fault and Moran basement fault in the center, High Zagros Reverse fault (HZF) in the north and Minab fault in the east. These tectonic lineaments constitute the weak zones that act as focal points for seismic activity. This region of Iran is very active and was the seat of many destructive and major earthquakes in the past. In this study, we investigated Gutenberg-Richter model describing a mathematical relationship between frequency and magnitude of an earthquake. We have attempted two objectives using the frequency of occurrence of earthquakes. First, a systematic study of b-values in Bandarabbas zone, Hajiabad Zone and Minab Zone show that initially there is an increase in b-value and then there is a return to normal within the vicinity of a forthcoming large earthquake. Second, we studied a relationship between the frequency and magnitude for those zones.

23 tables, 7 illus, 27 ref

022447   Edicha Jibril A (Geography Dep, Abuja Univ, Abuja Nigeria, P.M.B. 117, Garki, Email: edijib@yahoo.com) : Impact of bush burning on nutrient cycling in the federal capital Abuja, Nigeria. Trans Inst Indian Geogr 2007, 29(2), 178-84.

Examined the pattern of distribution of nutrients on soils subjected to regular burning with that of un-burnt soils for about five years in Abuja, the federal capital territory. Both transact line and quadrant techniques were employed to collect soil samples at a depth of O. 15 cm in both burnt and un-burnt plots which were analyzed for texture, pH, C.E.C, available phosphorus, soil organic carbon and exchangeable Ca, nig and K. The student t-test was employed in order to compare the value of soil properties in both burnt and un-burnt plots. From the analysis, there is a significant difference in soil organic carbon, total nitrogen, soil pH, exchangeable bases and cation exchange capacity amongst soils subjected to regular burning and that of the soils that were not burnt for a period of about five years. It is significant at both 0.01 and 0.05 levels.

2 tables, 29 ref

021414   Yu H;Joshi P K;Das K K;Chauniyal D D;Melick D R;Yang X;Xu J (NO, Kunming Inst of Botany, Chinese Academy of Sci, Kunming 650 204, Chin, Email: yuhaiying@mail.kib.ac.cn) : Land use/cover change and environmental vulnerability analysis in Birahi Ganga sub-watershed of the Garhwal Himalaya, India. Trop Ecol 2007, 48(2), 241-50.

Study analyses the land use/cover changes and environmental vulnerability of the Birahi Ganga sub-watershed in the Garhwal Himalaya, India. Satellite data of 1976, 1990 and 2005 shows that dense forest area increased from 1976 to 1990, which showed decreasing trend in the period 1990 to 2005; however, overall the results showed a net increase in the dense forest from 1976 to 2005. Contrary to this, grassland area declined in the initial period but increased between 1990 and 2005. Increase in agricultural land area was observed all through, whereas open forest and riverbed areas decreased. Spatial Principle Component Analysis (SPCA) showed that the environmental vulnerability initially decreased in the period 1976 to 1990, which then increased during the period 1990 to 2005. Most vulnerable areas were those on the warmer aspects, steep slopes and lower elevations. In these vulnerable sites land use/cover changes correlated with high human interference such as increased agricultural encroachment, forest resources extraction and grazing. Our observation shows that the human activities have increased recently in higher elevations as a response to increased population pressure. Related policies could be the underlying driving forces of the changes.

2 illus, 5 tables, 16 ref

021413   Yang X;Skidmore A K;Melick D;Zhou Z;Xu J (NO, Kunming Inst of Bot, Chiness Academy of Sciences, Heilongtan, Kunming, P.R. China-650 204, Email: xuefei@mail.kib.ac.in) : Towards an efficacious method of using landsat TM imagery to map forest in complex mountain terrain in northwest Yunnan, China. Trop Ecol 2007, 48(2), 227-39.

Mapping forest type using Landsat TM images encounters many problems especially when applied in montane landscapes with complex terrain. Evaluated the effects of selected data inputs and classification methods on the accuracy of forest type mapping in a complex terrain landscape in mountainous southwest China. Results show that the accuracy of a forest type map produced by the original Landsat TM bands data alone is not acceptable, but the integration of topographic data with Normalised Difference Vegetation Index (NDVI) and Principle Components (PCs) improves the mapping accuracy by 15% and 14%, respectively. In addition, the comparison of two-classification methods showed that a GIS expert system (EXPERT) outperforms the maximum likelihood classifier (MLC) by 9%. It is concluded that combination of topographic data together with NDVI or PCs enable production of more reliable and accurate forest maps in landscapes with complex terrain. Where reliable field knowledge is available, expert systems show potential for producing affordable forest type maps as accuracy as those obtained by conventional classifiers.

4 illus, 8 tables, 36 ref

021412   Vijay Kumar (National Institute of Hydrology, , Roorkee-247 667, Email: vijay@nih.ernet.in) : Spatial interpolation of groundwater levels by kriging. J Geol Soc India 2007, 69(5), 996-1004.

Command areas of canal irrigation projects in Rajasthan face the problem of rising groundwater level and manifestation of waterlogging at many places. To delineate the extent of waterlogged area, contour mapping of groundwater levels is required, which in turn require the interpolation of groundwater levels, measured in field at random points, at the grid nodes. In this paper, the applicability and usefulness of kriging to interpolate and map the spatial behaviour of groundwater levels has been demonstrated through a case study. Kriging is applied to interpolate the groundwater levels (above mean sea level) measured at 67 points in pre-monsoon season and at 61 points in post-monsoon season of 1991 in parts of the command area of Indira Gandhi Nahar Pariyojana (IGNP). With the use of measured elevations of the water table (above mean sea level), experimental semivariograms were constructed for both the seasons. Spherical, exponential and gaussian theoretical semivariogram models were fitted to the experimental semivariograms. The finally selected models were used to estimate the groundwater levels and corresponding standard deviation at the nodes of a square grid of 5km x 5km and to develop corresponding contour maps. The effect of using a common semivariogram, parameters estimated by taking the arithmetic mean of the semivariogram parameters for June and September data sets, on the cross validation results is also investigated.

9 illus, 2 tables, 23 ref

021411   Verma I J;Das H P;Kore P A;Balasubramanian R (NO, Meteorolical Office, Pune) : Peak rainfall period and its agricultural implication on crops grown in dry farming region of India. Mausam 2007, 58(4), 580-2.

1 illus, 12 ref

021410   Umrikar B;Thigale S S (Geology Dep, Pune Univ, Pune-411 007, Email: bnumrikar@unipune.ernet.in) : Sea water ingress study along the guhagar coast of Maharashtra with reference to the harmonious water resource development. J Geol Soc India 2007, 69(5), 933-42.

Konkan coast line in general and Guhagar coast line in particular is faulted in nature and endowed with a variety of coastal landforms and drainage patterns. Well inventory data reveals the presence of the beach rock-, mud-and basaltic aquifers. Out of these, the beach rock aquifer overlaps with spit-, the mud aquifer with flats- and basaltic aquifer with the uplifted abrasion platforms. The data also indicate that the groundwater level fluctuations for pre- and post-monsoon seasons range from 1.95 m to 3.10 m, 2.10 m to 2.90 m and 2.40 m to 5.75 m in the beach rock-, mud- and basaltic aquifers respectively. The average rise in groundwater levels due to sea water ingress under high tide condition is of the order of 0.59 m, 0.67 m, and 0.86 m respectively in the beach rock-, mud- and basaltic aquifers. Lowering of groundwater levels and pumping during pre-monsoon (summer) season are responsible for upconing of fresh- and sea water interface. It has been inferred that landward limit of the spit and abrasion platforms constitutes the ancient strand line whereas sandy beaches and mud flats the present strand line. The ancient strand line is the landward limit, and the fresh- and sea water interface is the vertical limit of subsurface sea water ingress. The regulations to be adopted for maintaining the delicate equilibrium of fresh- and sea water have been listed. The pros and cons of constructing engineering structures for preventing sea water ingress and strategy to enhance groundwater recharge for increasing fresh water column in the lower reaches of creeks, tidal inlets and their tributaries, without causing harm to the delicate ecosystem of mangroves, have been discussed.

5 illus, 2 tables, 23 ref

021409   Umar R;Ahmed I (Geology Dep, Aligarh Muslim Univ, Aligarh-202 002, Email: rashidumar@rediffmail.com) : Hydrochemical characteristics of groundwater in parts of Krishni-Yamuna basin, Muzaffarnagar District, U.P.. J Geol Soc India 2007, 69(5), 989-95.

The Krishni-Yamuna is a watershed in the most productive central Ganga plain. Systematic sampling was carried out in Krishni-Yamuna Basin in parts of Muzaffarnagar district, with a view to understand the sources of dissolved ions and to assess the quality of groundwater. Forty samples were collected from handpumps, covering an area of 434 square km. The quality of groundwater is suitable for irrigation purposes. As far as human consumption is concerned, the quality has a negative aspect in being SO₄-enriched. Na+K and Cl+SO₄ are dominating facies in cations and anions respectively. Based on chemical characteristics, the groundwaters have been divided into four groups. Group I and group II samples have acquired their chemistry through sediment-water interaction and dissolution mechanism. Group III and IV samples depict an increasing influence of anthropogenic factors.

9 illus, 2 tables, 6 ref

021408   Thipperudrappa N M;Yadupathi Putty M R (Civil Engineering Dep, Siddaganga Institute of Technology, Tumkur-572 103) : Rainfall variation over the last two decades a comparison between two districts of Karnataka. ISH J Hydraul Engng 2007, 13(2), 93-107.

The characteristics of rainfall and its inter- annual variation in Kodagu and Tumkur districts of Karnataka are compared using the statistical parameters including the mean, standard deviation, coefficient of variation and the Normalized anomaly. The characteristics of annual, seasonal and monthly rainfall are determined using the rainfall data for a period of two decades extending between 1983 and 2002 and the differences between rainfall variations in the two districts are established. It is found that the years of excess rainfall are 1984, 1992, 1994 and the only deficient year is 1987, in Kodagu. However, 1988, 2000 are the excess and 1985, 1990, 2002 are the deficient year in Tumkur district. The factors leading to excess and deficit are studied by analysing data of three years. The relationship between CV and the rainfall amount are established and discussed. Since the two districts represent two regions with different patterns of rainfall that characterize the state, it is hoped that the study helps to understand the differences in rainfall variation over the two regions.

8 illus, 8 table, 6 ref

021407   Tessy C P;Renuka G (Physics Dep, St Xavier's College, Thumba-695 586, Email: gitajose@hotmail.com) : Thermal diffusivity of soils in iso-hyperthermic temperature regime by harmonic analysis. Indian J Radio Space Phys 2008, 37(5), 360-5.

Soil temperatures at various depths at three stations in Kerala were subjected to harmonic analysis for a period of seven years. The amplitude of soil temperature wave at various depths decreases with higher order of harmonics. The thermal diffusivity of various soil layers for the first three harmonics have been calculated using amplitudes and phase angles of the soil temperature wave. The combined effect of first three harmonics gives more reliable values for thermal diffusivity in different soil layers.

021406   Taghipour S;khalili M;Noghreian M;Toraby G; Ghanei J (Geology Dep, Isfahan Univ, Iran, Email: tagipour.sedigheh@gmail.com) : Genesis of andradite-grossular garnets in altered igneous rocks from High Zagros salt domes, Iran. Ultra Scient phys Sci 2007, 19(3), 515-22.

Kaj, Dashtak and Doab salt domes are located in Zagros Range. These domes are composed of some infracambrian - Cambrian igneous, sedimentary and evaporate rocks. A clinopyroxcene and plagioclase is the main mineral constituent of igneous rocks, they are formed in magmatic stage. Garnet has formed in hydrothermal stage (Fluids rich in CaO, Fe₂O₃ and SiO₂) as veinlets. It's formed in XCO₂ = 0.6 and T = 520°C (P = 0.5 kb) conditions. In the life time of garnet genesis, pressure reduction of hydrothermal system has probably caused an abrupt change in garnet composition as revealed by zoning. Based on mineralogy garnets belong to ugrandite series and they are andraite. Garnet in this rocks is in which Si^4- = 2.97, Al³⁺ = 0.173, Fe³⁺ = 2.072, Ti³⁺ = 0.002, Ca²⁺ = 2.92, Fe²⁺ = 0.002, Mn²⁺ = 0.055.

021405   Suresh R;Janakiramayya V;Sukumar E R (India Meterorological Dep, , Chennai, Email: suresh.imd@gmail.com) : An account of fog over Chennai. Mausam 2007, 58(4), 501-12.

Climatologically (based on 1951-1980) the annual fog frequency of Chennai airport is 4.3 days. But. the operational aviation meteorological forecasters often experienced more number of foggy days during the past decade. Hence the fog frequency has been critically analysed based on current weather observations made by aerodrome meteorological office. Chennai during 1981-2002 (barring 1984 for which data is not readily available). It has been found that the annual frequency based on the study has shot up to 21.5 days. The most favourable period for tog over Chennai airport has been identified as January followed by February and March. The formation of fog has been mostly observed during 0000-0200 UTC although in good number of cases it was during 2200-2400 UTC. The most common duration of fog is 60-120 minutes albeit duration as high as 540-570 minutes are also probable. The low level (surface) nocturnal inversion frequency has alarmingly increased during 1990s and the inversion is almost a day-to-day phenomenon during 2000s. Rapid urbanisation, vehicular traffic and industrial growth could be the cause for the increased atmospheric pollution which has increased the nocturnal stability conditions as well the tog frequency. Visibility as low as zero bad been recorded on a number of cases and their causes have been analysed. Neutral or absolutely unstable stratification at 1200 UTC coupled with high relative humidity and high concentration of pollution cause the fog to form from 2200 UTC onwards and the nocturnal surface inversion/isotherm at 0000 UTC maintains the fog. Though the low level inversion maintains the fog once it is formed already, inversion alone is not a sufficient condition for the formation of fog.

4 illus, 9 tables, 5 ref

021404   Suresh Babu D S;Padmalal D;Arun P R (Centre for Earth Science Studies, Akkulam, Thiruvananthapuram-695 031, Email: dssbabu@gmail.com) : Watershed analysis of two forest catchments from Western Ghats, South India and its significance for mitigation of reservoir siltation. J Geol Soc India 2007, 69(5), 1077-87.

Estimation of water balance and sediment yield pertaining to two forest watersheds of southern India was carried out as part of the forest conservation program in Kerala State. The tropical watersheds namely Upper Peppara (<126>80 km²) and Upper Neyyar (<126> 140 km²) of southern Kerala region host two important wildlife sanctuaries maintained in the Western Ghats of Indian subcontinent, which have high biodiversity values. The watershed evaluation conducted during the period 1995-2000 reveals that Peppara reservoir catchment yields an average of 1600 tons of suspended sediment and 126 Mm³ of run off water every year. On the other hand, Neyyar reservoir at Full Reservoir Level (FRL) carries a suspended sediment load of 1400 tons during the peak monsoon month of June and it receives 207 Mm³ of run off from its catchment annually. Unit plot measurements for soil loss indicate that grassland yields substantially high sand-silt material, of the order of one ton per hectare annually. A management plan map for the Upper Neyyar watershed has been prepared taking into consideration of landscape features. One micro watershed, Panampara (6.73km²) falling within Peppara sanctuary was closely monitored to check its physical health. A number of locally feasible conservation strategies have been proposed to improve the water holding capacity as well as to minimise soil erosion in this subwatershed area. Periodic and manual silt removal from reservoirs during summer periods is recommended to maintain the storage capacity rather than constructing an upper dam or increasing the height of existing dam, as actively being considered.

8 illus, 4 tables, 12 ref

021403   Subhash Chandra K C;Pattabhi Ramaiah N R (No.75, 5th 'A' Main Road, 4th Cross, R.P.C. Layout, Vijayanagar II Stage, Bangalore-560 040, Email: subcha@gmail.com) : Springs in limestone environs of Karnataka. J Geol Soc India 2007, 69(5), 1111-17.

The geohydrological environs of springs in the limestone formations of Karnataka are complex, but interesting. Springs abound in Western Ghats. But, geomorphic set up of the terrain is so hostile that many are not accessible. In the Eastern Maidan Tract, the limestone formations of Bhima Group host most of the springs as compared to those of Dharwar and Kaladgi Super Groups. The limestone formations in the stratigraphic sequences of Sargurs, Bababudans and Badamis form minor litho-constituents and do not have much significance as regard to the occurrence of springs. A few of the springs, once active in Eastern Maidan Tract have now become dormant, the cause that could be attributed to a long sustained anthropological activity. The chemical quality of spring waters in limestone formations of Chitradurga Group and in particular of those in Western Ghats are suitable for domestic and agricultural usage. Springs located in the limestone formations of Kaladgi Super Group and Bhima Group are quality wise alkaline, contain fluoride and certain other dissolved constituents beyond the permissible limits.

1 illus, 2 tables, 11 ref

021402   Subba Rao N;Prakasa Rao J;Subrahmanyam A (Geology Dep, Andhra Univ, Visakhapatnam-530 003, Email: srnandipati@rediffmail.com) : Principal component analysis in groundwater quality in a developing urban area of Andhra Pradesh. J Geol Soc India 2007, 69(5), 959-69.

Principal component analysis (PCA) of the chemical variables of groundwater is employed to interpret the relationships with specific processes that control the quality of water. Groundwater samples collected from the Guntur urban area, Andhra Pradesh were analyzed for major ion chemistry. The PCA separates the chemical variables into three principal components, which together account for 77.20% of the total variance. The principal component-I (PC-I) is dominated by TDS, Na⁺, Cl^-, SO₄^2- and K⁺. The principal component-II (PC-II) is influenced by pH and CO₃^2-. The principal component-III (PC-III) is governed by NO₃^-. These three principal components are identified with the processes of salinity, alkalinity and pollution, which are considered as lithologically and non-lithologically controlled factor, lithologically controlled factor and non-lithologically controlled factor, respectively. Areal distribution of the principal component scores show that the higher positive scores of PC-I, PC-II and PC-Ill arc randomly distributed, but do not coincide with one another, which suggest the local modifications of PC-I due to the regional flow system of groundwater, whereas PC-II and PC-Ill are the pathways of recharge zones via soil and anthropogenic activity operated independently, following the natural environmental hydrogeochemical evolution of groundwaters. Identification of these zones helps to take appropriate management measures to improve the quality of groundwater for sustainable development of the area.

7 illus, 4 tables, 12 ref

021401   Srivastava H N;Bhattacharya S N;Rao D T; Srivastava S (128, Pocket-A, Sarita Vihar, New Delhi, Email: hn_srivastava@hotmail.com) : Strange attractor in earthquake swarms near Valsad (Gujarat), India. Mausam 2007, 58(4), 543-50.

Valsad district in south Gujarat near the western coast of the peninsular India experienced earthquake swarms since early February 1986. Seismic monitoring through a network of micro earthquake seismographs showed a well concentrated seismic activity over an area of 7 x 10 km² with the depth of foci extending from 1 to 15 km. A total number of 21.830 earthquakes were recorded during March 1986 to June 1988. The daily frequency of earthquakes for this period was utilized to examine deterministic chaos through evaluation of dimension of strange attractor and Lyapunov exponent. The low dimension of 2.1 for the strange attractor and positive value of the largest Lyapunov exponent suggest chaotic dynamics in Valsad earthquake swarms with at least 3 parameters for earthquake predictability. The results indicate differences in the characteristics of deterministic chaos in inlraplate and interplate regions of India.

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021400   Srivastava A K;Dandekar M M;Kshirsagar S R; Dikshit S K (India Meteorological Dep, , Pune-411 005, Email: aksncc2004@yahoo.co.in) : Is summer becoming more uncomfortable at Indian cities?. Mausam 2007, 58(3), 335-44.

The recent decades have witnessed significant increase in temperatures both on global and regional scale. Some specific locations in India like Orissa and Andhra Pradesh have experienced unusually heat wave conditions resulting in increase in heat stress associated illnesses and mortality. There is a general belief that cities have become more uncomfortable during summer, particularly in the recent years. The present study is an attempt to examine the trend in discomfort over the Indian cities measured by an index (Thermo-Hygrometric Index: THI). Results show that in general there is an increasing trend in the discomfort from the last 10 days of April to June over most of the Indian cities. Further, frequency and maximum length of continuous periods exceeding abnormal discomfort values over a number of stations are steadily increasing particularly during May and June.

10 illus, 18 ref

021399   Srinivasamoorthy K;Chidambaram S;Anandhan P (Earth Sciences Dep, Annamalai Univ, Tamilnadu-608 002, Email: moorthy_ks@yahoo.com) : Control of rock weathering on the chemical composition of groundwater in salem District, Tamilnadu, India. Ultra Scient phys Sci 2007, 19(3), 367-78.

Rock and groundwater samples representing major lithology like Peninsular gneiss, Charnockite and Calc gneiss were collected from Salem district of Tamilnadu, India to infer the influence of rock weathering on the chemistry of groundwater. Rocks samples were sieved in Mesh for various size fractions and made to react with double distilled water and water samples were collected at a time gap of 45 days for a period of one year (eight times), groundwater samples were also collected from major lithology and analyzed for major ions. The rock reacted samples reveal mole ratios of HCO3/SiO2 dominantly fall in the Feldspar. Biotite and Pyroxene weathering zones. Factor analysis suggests direct reaction, dissolution, reworking on the adsorbed mineral faces, diffusion and ion exchange are the principal factors controlling the water chemistry of rock water interacted samples. The relative mobility of ions is lesser in Charnockite than the other two rock types because of their high resistance to weathering. It is interpreted that trend of relative mobility of ions remain to be same in experimental values (in lab) and in groundwater condition (in field) but in different ratios.

5 illus, 1 table, 9 ref

021398   Singh R K;Sureja A K (College of Horticulture and Forestry, Central Agricultural University, Pasighat-791 102, Email: ranjay_jbp@rediffmail.com) : Indigenous knowledge and sustainable agricultural resources management under rainfed agro-ecosystem. Indian J Tradl Knowledge 2008, 7(4), 642-54.

Demonstrates the tribal farmers' wisdom, perception and their criteria developed for the agricultural resources conservation and survival under the risk prone agro-ecosystem of Dindori district of Madhya Pradesh. The investigation was carried out in seven villages dominated by Gond, Baiga and Pradhan tribes. Conventional and participatory methods were applied to record the data. The result indicates that, despite the increasing commercialization of agriculture, the great majority of the farmers in the area are peasants, or small-scale producers. After centuries of cultural and biological evolution, traditional farmers have developed and inherited complex farming systems, adapted to the risk prone situations. These have helped them to conserve and sustainably manage harsh environments and meet their subsistence need without depending on costly energy based inputs. Agro-ecological and ethno-ecological evidence in vogue among the tribal community increasingly indicates that these systems are productive, sustainable, ecologically sound, and tuned to the social, economic, and cultural features of the local tribe. Some of the cultural adaptations that farmers have developed in the area include: domestication and conservation of diversity of plants and maintenance of a wide genetic resource base. Farmers are competent to make vertical agricultural development through the series of traditional resource conserving practices, variety conservation, weed, pest, nutrient, and water management practices to deal with socio-environmental changes. Scientists involved in agricultural research and development must try to learn, systematize and incorporate the farmers' practices, before this wealth of practical knowledge is lost forever, given that most traditional farming systems are rapidly disappearing in the face of major social, economic and political changes occurring in developing societies.

021397   Singh O P (India Meteorological Dep, , New Delhi, Email: opsingh@imdmail.gov.in) : Interannual variability of the Arabian sea warm pool intensity and its association with monsoon onset over Kerala. Mausam 2007, 58(3), 345-50.

The relationships between the Arabian Sea warm pool intensity, Southern Oscillation (SO) and the monsoon onset have been discussed. The results show that the peak intensity of the warm pool in the Lakshadweep Sea is significantly correlated with the monsoon onset date over Kerala. Warmer Sea Surface Temperature (SST) anomalies in the warm pool region during April-May are associated with delayed monsoon onset over Kerala though the cause-and-effect relationship is not known. The Southern Oscillation Index (SOI) of March can provide predictive indications of the peak intensity of the warm pool which, normally occurs during April.

6 illus, 9 ref

021396   Singh A K;Mondal G C;Singh S;Singh P K;Singh T B;Tewary B K;Sinha A (Geoenvironment Div, Environmental Management Group, Central Mining Research Institute, Barwa Road, Dhanbad-826 001, Email: singhak@yahoo.com) : Aquatic Geochemistry of Dhanbad, Jharkhand: source evaluation and quality assessment. J Geol Soc India 2007, 69(5), 1088-1102.

Surface, subsurface and mine water collected from rural, urban, industrial and coal mining of areas of Dhanbad district have been analysed to assess the major ion chemistry, the weathering and geochemical processes controlling the water composition and suitability of water for domestic, industrial and agricultural uses. Ca, Mg, and HCO₃ dominate the chemical composition of the water chemistry. However, in the mine water and water samples collected from mining areas, high concentration of SO₄ has been observed. Water chemistry of the study area strongly reflects the dominance of continental weathering and higher concentration of SO₄, Cl and TDS in some samples indicates mining and anthropogenic impact on water quality. The high contribution of (Ca+Mg) to the total cations, relatively high (Na+K)/TZ+ ratio (0.27) and low equivalent ratio of (Ca+Mg)/(Na+K) i.e. 3.6 suggest combined influence of carbonate and silicate weathering. The higher values of C-ratio for most of the surface and subsurface water signify that carbonic acid weathering is the major proton producer in these waters. However, the low C-ratio for the mine water (average 0.22) and the waters collected near the coal mining areas suggests that sulphide oxidation and/or coupled reactions (involving both carbonic acid weathering and sulphide oxidation) control the chemical quality in the mining areas. The quality assessment of surface and subsurface water shows that water is suitable for domestic use with few exceptions. The calculated values of SAR, RSC and sodium percentage indicate that water can be used for irrigation without any hazard.

7 illus, 3 tables, 34 ref

021395   Sikdar P K;Adhikari S K;Bhattacharya B B (Environment Management Dep, Indian Institute of Social Welfare and Business Management, Kolakata-700 073, Email: p_sikdar@hotmail.com) : Lineament density modelling to identify high potential aquifers in hard rock areas. J Geol Soc India 2007, 69(5), 1118-31.

Lineament density modelling indicates that the major lineament density axes show NE-SW and NW-SE trends. These two trends indicate that the regional ground water flow system is controlled mostly by the Tel river. Lineament density in most of the area is low i.e. below 0.2 km/sq. km. To demarcate potential aquifer zones for future development, technique of thematic overlay has been utilized using lineament density and long-term water table fluctuation. The overlay procedure indicates that in general the potentiality of the aquifer for future development is medium. In the Nawapara district the potentiality of the aquifer for future groundwater development is more than in Kalahandi district. Therefore in Kalahandi district artificial recharge of groundwater including roof top rainwater harvesting should be carried out to overcome the shortage of water for drinking purpose.

12 illus, 7 tables, 8 ref

021394   Shende R R;Ravindran U;Bhondave S D; KondeDeshmukh A R (India Meteorological Dep, , Pune) : Role of aerosols in deciding pH of rainwater. Mausam 2007, 58(4), 513-24.

Nature of precipitation - alkaline or acidic - depends upon the concentration of major water soluble inorganic gaseous and soil derived particulates dissolved in it. if concentration of cations is higher than that of anions, the precipitation becomes alkaline and vixe-a-versa. pH is the main parameter indicating the nature of precipitation. If pH of the solution is <60> 5.65. it is acidic and <62> 5.65, alkaline, in the pH scale ranging between 0 & 14. Difference in the chemical composition of rainwater having pH in the alkaline range and acidic range has been studied in this paper. For this purpose, precipitation chemistry data of Allahabad, Jodhpur, Mohanbari and Nagpur for the period 1988-97 have been considered. APWM & S.D. have been worked out. Precipitation chemistry data considering APWM values in acidic range and in alkaline range have been separated and compared. Coefficients of correlation have been calculated in possible cation-anion combinations. It is seen that the lowest pH values (monthly mean) have been recorded during 1997 - MHB (3.77), NGP (4.12), both in acidic range. % Frequency of occurrences of pH values in acidic range was the highest at Mohanbari (66%) in the study period. Jodhpur recorded all pH values in alkaline range indicating influence of soil derived alkaline particulates. Among cations Ca⁺² has shown its dominance over all cations. Jodhpur has recorded the highest APWM value of Ca⁺² (9.27 mg/lit) in 1997.

3 illus, 6 tables, 26 ref

021393   Sharma G K;Bora J (Geology Dep, Kumaun Univ, Nainital-263 002) : Pleistocene radiolaria from the Kerguelen plateau, Leg 119, sections 1H and 2H. J Palaeont Soc India 2007, 52(1), 27-38.

Twenty core samples from the Leg 119 Site 745 (Sections 1H to 2H) on the Kerguelen-Heard Plateau in the Southern Ocean region yielded, thirty-eight well-preserved radiolarian taxa which were studied and illustrated. The systemalics, biostratigraphy, distribution in the core and comparison with radiolarian occurrences from other regions arc presented. Two radiolarian zones are established viz. Psi and Omega in the sections. Ten new species arc described but not formally named. The primary purpose is to present a first detailed Antarctic Pleistocene radiolarian data and refined biozonc boundaries for comparative studies with other parts of the Antarctic region.

3 illus, 90 ref

021392   Sharma C;Budhraja N;Chatterjee S (NO, , Lucknow-226 007) : Pollen rain studies in the environs of Tajmahal, Agra. J Palaeont Soc India 2007, 52(1), 111-17.

Attempts to evaluate the palynoflora in the environs of the Taj complex. The overall pollen assemblage depicts that the environs of Taj arc charged with palynomorphs from higher as well as lower plant groups which include trees, shrubs, herbs, ferns, bryophytcs, fungi, etc. However, a few recovered taxa arc most probably exotic as they do not grow cither in the area or in the vicinity. Pollen analysis of spider's webs in the present study has opened an important frontier in evaluating the modern pollen rain. Spider's webs are often quite rich in pollen/spores, etc., and have proved to be a reliable parameter, particularly when soil samples are cither unproductive or remain poor in pollen yield. Furthermore, comparison of recovered taxa from surface soil and web has amply demonstrated that spider's webs are as good as soil samples and sometimes even better for pollen rain studies. Retrieval of fungal spores from the walls of the main gale of the Taj complex, must be taken care of as their deposition is very likely to affect the lustre of the marble monument in the long run.

2 illus, 1 table, 9 ref

021391   Sengupta S M (NO, , P-45/B, Hijli Coop. Society, Kharagpur-721 306) : Interlinking of rivers May cause geomorphic changes. J Geol Soc India 2007, 69(5), 1134-5.

5 ref

021390   Semwal G;Giri R K (Snow and Avalanche Study Establishment, Research and Development Center, Sector 37-A, Chandigarh-160 036, Email: rkgiri_ccs@rediffmail.com) : Precipitation simulation of synoptic scale systems over western Himalayan region using advanced regional prediction system (ARPS) model. Mausam 2007, 58(4), 471-80.

Operational weather prediction over western Himalayan region is a challenging job due to scarcity of data and complex topography that interacts with approaching weather system. Accurate prediction of complex weather phenomena requires dense data network which is difficult to establish in mountain due to complex terrain and hostile weather conditions over Himalaya. The alternate method to overcome this problem is by ingesting three-dimensional meteorological variables from global model's analysis and forecast values as initial and lateral boundary conditions in meso-scale numerical models. Simultaneously, data assimilation is a potential tool in which non-conventional [satellite, radar and Automatic Weather Station (AWS)] and conventional (surface and upper air observations) data are ingested in the numerical models to generate high resolution and accurate initial fields for the initialization of the mesoscale model. In the study, Advanced Regional Prediction System (ARPS) model has been used for the prediction of synoptic weather system known as Western Disturbance (WD) that affects the weather of western and central Himalaya during winter period (November - April).The ARPS model has been selected for this study because the model has its own objective analysis and quality control system. It has the capacity to ingest the satellite, Doppler weather radar data and other types of observations. Its assimilation system can also be used to overcome the problem of data scarcity in Himalayan region. In this study, initial and lateral boundary fields are taken from the T-80 spectral global model operationally used at National Centre for Medium Range Prediction (NCMRWF), Noida (UP), India. The global model's analysis was taken as the initial condition and 24 hour's interval forecasts as lateral boundary conditions. The model has been used for the simulation of few WDs for 96 hours (Four days). The comparison of ARPS simulation with T-80 forecast shows that the ARPS model could produce better results in respect of the circulation of WDs and hence it can be utilized for operational weather prediction over the Indian region.

5 illus, 2 tables, 8 ref

021389   Seetharam K (Meteorological Centre, , Gangtok) : Application of Markov chain model to daily rainfall of Jalpaiguri station. Mausam 2007, 58(3), 396-9.

4 ref

021388   Satheesh Herbert Singh D;Lawrence J F (Geology Dep, Presidency College, Chennai-600 005, Email: geo_herbert@rediffmail.com) : Groundwater quality assessment of shallow aquifer using geographical information system in part of Chennai City, Tamil Nadu. J Geol Soc India 2007, 69(5), 1067-76.

Water is essential for life. When, the available surface water resource does not fully meet the demand, people opt for groundwater extraction. Chennai is one such place, where the present day need is partly met by subsurface water. The quality of groundwater is as important as its quantity. In this study Quality assessment of available groundwater of shallow depth has been carried out using various chemical parameters and with the help of Geographical Information System (GIS).

14 illus, 2 tables, 8 ref

021387   Samui R P;Chattopadhyay N;Sabale J P (Agricultural Meteorological Div, , Pune, Email: agrimet_pune@yahoo.com) : Weather based forewarning of leaf folder attack on kharif rice and operational crop protection at Pattambi, Kerala. Mausam 2007, 58(4), 525-36.

Kharif and Rabi rice grown extensively over Kerala is mainly infested by gall midge, leaf folder and green jassid in kharif season. Under favourable weather conditions leaf folder become the dreaded pest and cause considerable damage to the crop. The study revealed that maximum and minimum temperature, morning and afternoon relative humidity and weekly total of rainfall have profound effect on the development of leaf folder at their successive generations on kharif rice crop. Weather based multiple regression models for the peak infestation period for each of the generations of the pest were developed using data for the period 1987-99 and validated using observed meteorological as well as pest data for 2000-2001. Based on the findings of this study pest weather calendar for leaf folder of kharif rice was prepared. This calendar would be useful for early warning and operational rice crop protection from leaf folder attack.

6 illus, 1 table, 7 ref

021386   Samadder R K;Kumar S;Gupta R P (Earth Sciences Dep, Indian Institute of Technology, Roorkee-247 667, Email: rpgesfes@iitr.ernet.in) : Conjunctive use of well-log and remote sensing data for interpreting shallow aquifer geometry in Ganga Plains. J Geol Soc India 2007, 69(5), 925-32.

Study of aquifer geometry is essential for proper development and utilization of groundwater resources. In this study, a systematic approach has been made in the analysis of shallow aquifer geometry in the western Ganga Plains, Uttar Pradesh, by integrating the well-log and remote sensing data. The study includes mapping of neotectonic lineaments from remote sensing data, and determination of aquifer depth and lithological details from the well-log data. The well-log data indicate that the region has varying thickness of alluvium composed of alternating sand, kankar and clay strata. By integrating the remote sensing and well-log data sets, sub-surface geological sections have been developed to interpret the aquifer geometry. The aquifers are found to show significant variation in nature and geometry from place to place. At some places, the lineaments on remote sensing images are in conformity with faults interpreted from well-log data, whereas at others, buried faults have been interpreted. The aquifers formed by paleochannels is particularly striking, being unconfined in nature and mainly consisting of medium to coarse sand, along with pebbles, cobbles and kankar.

5 illus, 1 table, 15 ref

021385   Saha D;Upadhyay S;Dhar Y R;Singh R (Central Ground Water Board, 6th Floor, Lok Nayak Bhawan, Patna-800 001, Email: dsaha002@yahoo.com) : Aquifer system and evaluation of its hydraulic parameters in parts of south Ganga Plain, Bihar. J Geol Soc India 2007, 69(5), 1031-41.

Ground water within the sand layers occurs under semi-confined to confined condition. Transmissivity ranges from 74.9 To more than 20,000 m²/day. The potentiality of the aquifers increases towards north but there is considerable improvement in aquifer parameters from Nawada to Fatwa Formation. In Nawada Formation, the hydraulic conductivity generally ranges from 10-20 m/day and the average yield factor has been found to be 0.99 m³/hr/m/m, whereas, in Fatwa Formation the average hydraulic conductivity and yield factor have been found to be 229 m/day and 2.75 m³/hr/m/m respectively. Based on the hydrogeological properties and aquifer hydraulic parameters, the alluvial plains has been divided into three zones. The Zone-1, covering the Fatwa and northern part of the Nawada Formations, is characterised by highest ground water potential. The safe distance between deep tube wells in this unit worked out to be 20 km for 8 hours of pumping with 150 m³/hr discharge. The safe distance in Zone-2 covering the central part has been found as 6.5 km for 6 hours pumping with 100 m³/hr discharge. The Zone-3 covering the southern part, the safe distance worked out as 1 km for 4 hours pumping with 50 m³/hr discharge.

7 illus, 4 tables, 24 ref

021384   Roy P K;Mazumdar A (School of Water Resources Engineering, Jadavpur Univ, Kolkata-700 032, Email: pk1roy@yahoo.co.in) : Hydrology and drought in the flood region of damodar river basin. J Geol Soc India 2007, 69(5), 1011-19.

This paper is made to thoroughly investigate the important hydrological features of the flood region mainly in the Damodar river basin which represents the first Indian attempt to treat an entire river system from source to mouth in order to achieve the maximum possible benefits also it has been applied for first time in India for covering the water and land resources. This was the first river valley that was being implemented through a regional development corporation named Damodar Valley Corporataion (DVC). The climatological data are used in the study include temperature, precipitation, sunshine duration, radiation, humidity, wind speed and potential transfer evaporation. The paper also includes the stream flow records of the Damodar river catchment up to Durgapur barrage being the outlet point of the DVC System. The long-term hydrological data of five different subcatchments (i.e. Tilaiya, Konar, Maithan, Panchet and Durgapur) have been analysed. The effect of changes in the behaviour of the hydrological factors on the degree of aridity is also assessed. The study clearly indicates significant changes in the hydrological behaviour of the region characterised by an increase in temperature levels and a substantial reduction in rainfall and river flows.

4 illus, 5 tables, 9 ref

021383   Rokade V M;Kundal P;Joshi A K (Postgraduate Dep, of Geology, RTM Nagpur Univ, Law College Campus, Nagpur-440 001, Email: vishu_mr@yahoo.com) : Groundwater potential modelling through remote sensing and GIS: A case study from Rajura taluka, Chandrapur District, Maharashtra. J Geol Soc India 2007, 69(5), 943-8.

Our very own survival on earth essentially depends on the water, nature's valuable gift to all life forms. The optimal and sustainable development of the resource is very crucial so that it is accessed reliably to avoid any future problems regarding its qualitative and quantitative availability. The interpretation of remote sensing data in conjunction with conventional data and sufficient ground truth information makes it possible to identify and outline various ground features such as geological structures, geomorphic features and their hydrologic characters, that may serve as direct or indirect indicators of the presence of ground and surface water. Remote sensing and Geographical Information System (GIS) have emerged as essential tools to meet ever-increasing demand for more precise and timely information. These techniques permit rapid and cost effective natural resource survey and management. Remotely sensed data provides unbiased information on geology, geomorphology, structural pattern and recharging conditions, which logically define The groundwater regime of an area. The present study is an attempt to delineate different groundwater potential zones in Sasti watershed, Taluka Rajura of Chandrapur district (Maharashtra) using an integrated approach of Remote Sensing and Geographical Information System.

6 illus, 2 tables, 8 ref

021382   Rastmanesh;Fatemeh;Farid M (Earth Sciences Dep, College of Sciences, Shiraz Univ, Shiraz 71454 (Iran)) : Alteration mapping using decorrelation stretching on ASTER data a case study: Takab area, NW Iran. Ultra Scient phys Sci 2007, 19(2), 239-46.

Takab geothermal basin is a significant mineralized zone in Iran. Beside Zarshuran, which is an important Au-As mine, other deposits and prospects of Au-Sb-Hg-As mineralization occur in Takab area. These deposits are characterized by producing of alteration haloes. In this study alteration mapping using ASTER data is evaluated for determination of potentially toxic metal (PTMs) sources. Decorrelation stretching process using spectral characteristics of argillic and silicic alteration zones, could successfully map these sources. The results show that alteration mapping beside exploration and geological purposes can also serve to determinate PTMs sources. Hence alteration mapping is a useful approach in large scale environmental studies.

6 illus, 3 tables, 21 ref

021381   Ram Niwas;Sastri C V S;Khichar M L (Agriculture Meteorology Dep, CCS Haryana Agricultural Univ, Hisar) : Energy indices for pearl millet [Pennisetum glanum (L.) R. Br] crip. Mausam 2007, 58(3), 399-402.

8 ref

021380   Raj Y E A;Muthuchami A;Ramanathan A N (NO, Regional Meteorological Centre, Chennai, Email: yearraj@satyam.net.in) : Asymmetric structure of a severe cyclonic storm of north Indian ocean as derived through INSAT OLR data. Mausam 2007, 58(4), 481-500.

The existence of systematic asymmetry in the cloud structure within the regime of Severe Cyclonic Storms (SCS) of North Indian Ocean has been studied based on instantaneous six hourly observations of INSAT Outgoing Long wave Radiation (OLR) data of SCS days for the period 1993 to 2004 for the two basins of north Indian Ocean. The OLR data was of 2.5° x 2.5° resolution for the period upto 1999 and was of 1° x 1° resolution for the subsequent period. The mean spatial distribution of OLR with reference to the centre of SCS was derived for the two basins and various seasons. Another set of mean distributions of OLR was also generated after rotating the individual profiles with reference to the direction of motion of the SCS. Separate mean profiles when the SCS approached the coast and for east and westward moving SCS were also derived. The height of cloud top for the various cases and the horizontal extent of SCS in various directions were computed. An index of asymmetry was defined and derived for the various categories. Systematic and organised asymmetry in the SCS regime was detected from the mean OLR distributions in respect ' of most of the categories. For the pre-monsoon Arabian Sea SCS the sector of lowest OLR was the southwest / west or left rear sector. For post-monsoon SCS, the west / northwest sector reported the lowest OLR values for both the basins. It was found that generally the SCS slightly weakened in intensity prior to landfall. The asymmetry could be satisfactorily explained by invoking normal environmental flow and direction of motion of the SCS. The β - effect played modest role in some specific cases. The Bay of Bengal SCS were found to be more intense for a given season. For a given basin premonson SCS were the most intense.

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021379   Poornachandra Rao G V S;Singh S B;Prasanna Lakshmi K J (Paleomagnetism Laboratory, National Geophysical Research Institute, Hyderabad-500 007, Email: director@ngri.res.in) : Neoproterozoic palaeomagnetic results of Jodhpur sandstone, Marwar supergroup, western Rajasthan. J Geol Soc India 2007, 69(5), 901-8.

The Jodhpur Sandstone (Marwar Supergroup) is investigated from three sites in western Rajasthan, India, using thermal arid AF demagnetization techniques. The Characteristic Remanent Magnetic (ChRM) direction isolated is having a normal polarity of Dm = 19.59°, Im = +46.27° (K = 206.19, α₉₅ = 5.63°, N = 3) and yielded a Virtual Geomagnetic Pole (VGP) at λp = 32.4° S, Lp = 51.3° E (δp = 4.63°, δm = 7.22°). The palaeomagnetic data of the Jodhpur Sandstone is in good agreement with that of the Upper Rewa Sandstone of the Vindhyan Supergroup rocks that are correlated with the Jodhpur Sandstone on lithological similarities. The Malani Rhyolite overlain by the Jodhpur Sandstone with well constrained radiometric and palaeomagnetic results thus assign a maximum age of < 745ñ10 Ma to the Jodhpur Sandstone and in turn to the Rewa Sandstone of the Vindhyan Supergroup which were correlated with them. This correlation helps in constraining the age of the Rewa Group rocks in the Upper Vindhyans, which are devoid of any fossil evidence and suitable radiometric material to date them.

4 illus, 45 ref