Evaluation of groundwater quality in Madurai City,South India for drinking,irrigation and construction purposes

The present research is contributed on groundwater quality, its deterioration and evaluation based on drinking, irrigation, and construction standards. The study area chosen for investigation on water quality is the Tirunagar (TN) area, located in the south-west of Madurai City. The TN area was formerly an agricultural land but presently a residential area that is at a starvation of drinking water quality. A total of 49 bore well samples from TN and Amaithisolai (AS) were investigated for drinking, irrigation, and construction qualities based on various physicochemical parameters. The chemistry of groundwater samples was reflected from very hard and noncarbonate-dominating species. TN was recorded with higher inorganic species in groundwater sources than AS. The Water Quality Index values indicated that 75 % of the samples fall under excellent category and the positive Langelier Saturation Index values of the samples highlighted their tendency to deposit calcium carbonate. The Gibbs plot showed that AS samples were categorized under the domination of rock–water interaction whereas the TN samples under evaporation zone. The US Salinity Laboratory Staff plot depicted that all the groundwater sources at AS with C3S1 type whereas 88 % of the TN sources represented C4S1 type. The results from Wilcox diagram for irrigation inferred that the groundwater sources at AS were permissible, but 68 % of the samples at TN was registered under unfit type. The suitability of groundwater from the knowledge of residual sodium carbonate, sodium absorption ratio, and sodium percentage was also investigated. The perception based on standards recommended the groundwater sources for construction activities. The contribution of ionic species and inter-relationship among the ions were also interpreted from the knowledge of statistical studies.     

Spectroscopic studies of solar corona VI: Trend in line-width variation of coronal emission lines with height independent of the structure of coronal loops

We have obtained spectroscopic observations in coronal emission lines by choosing two lines simultaneously, one [Fe x] 6374 Å and the other [Fe xi] 7892 Å or [Fe xiii] 10747 Å or [Fe xiv] 5303 Å. We found that in 95 per cent of the coronal loops observed in 6374 Å, the FWHM of the emission line increases with height above the limb irrespective of the size, shape and orientation of the loop and that in case of 5303 Å line decreases with height in about 89 per cent of the coronal loops. The FWHM of 7892 Å and 10747 Å emission lines show intermediate behavior. The increase in the FWHM of 6374 Å line with height is the steepest among these four lines. We have also studied the intensity ratio and ratio of FWHM of these lines with respect to those of 6374 Å as a function height above the limb. We found that the intensity ratio of 7892 Å and 10747 Å lines with respect to 6374 Å line increases with height and that of 5303 Å to 6374 Å decreases with height above the limb. This implies that temperature in coronal loops will appear to increase with height in the intensity ratio plots of 7892 Å and 6374 Å; and 10747 Å and 6374 Å whereas it will appear to decrease with height in intensity ratio of 5303 Å to 6374 Å lineversus height plot. These findings are up to a height of about 200 arcsec above the limb. The varying ratios with height indicate that relatively hotter and colder plasma in coronal loops interact with each other. Therefore, the observed increase in FWHM with height above the limb of coronal emission lines associated with plasma at about 1 MK may not be due to increase in non-thermal motions caused by coronal waves but due to interaction with the relatively hotter plasma. These findings also do not support the existing coronal loop models, which predict an increase in temperature of the loop with height above the limb.     

Sediment and carbon storages in the Yahagi River Delta during the Holocene,central Japan

We estimated stored sediment and carbon during the Holocene for each layer of the Yahagi River Delta, central Japan and discussed the provenance of stored carbon. To estimate the bulk density and the carbon content of each layer, we collected two 30 m deep undisturbed cores. The volume of each layer was calculated using ArcView 3D analyst. Although the volume ratio of each layer to the total volume was calculated to be 9.5% for the top mud layer, 34.9% for the upper sand layer, 32.8% for the middle mud layer and 22.9% for the lower sand layer, the mass ratio of each layer to the total mass was calculated to be 8.5, 40.9, 25.2 and 25.4%, respectively, and the stored carbon ratio in each layer to the total stored carbon was 20.4, 4.7, 55.9 and 18.9%, respectively. These results suggest that the top mud and middle mud layers have a significant role as a place for carbon sequestration during postglacial time. Total stored carbon in the study area of only 92.1 km² was estimated at 26 Tg C, which is equivalent to 0.003% of atmospheric carbon. This suggests that deltas on the globe have accumulated a massive amount of carbon during the evolution. The inorganic carbon ratio to total carbon reached more than 45% around the boundary between the middle mud and lower sand layers. The increasing trend in the C_org/N_total ratio accompanied with a decrease in δ¹³C from the bottom to the top horizon in the middle mud layer indicates a gradual increase in terrestrial organic matter contribution. The relative proportion of terrestrially derived materials decreases with increasing distance seaward.     

Characteristics and formation of rain forest soils derived from late Quaternary basaltic rocks in Leyte,Philippines

This study was conducted to evaluate the physical, chemical, and mineralogical characteristics of rain forest soils derived from late Quaternary basaltic rocks in Leyte, Philippines. Four sites along a catena were selected at an elevation of 75–112 m above sea level with an average annual rainfall of 3,000 mm and an average temperature of 28°C. Results indicate that the soils are deep, clayey, and reddish in color, which is indicative of the advanced stage of soil development. They also posses excellent physical condition (friable and highly porous) although they are plastic and sticky when wet as is usual for clayey soils. In terms of chemical characteristics, the soils are acidic with low CEC values and generally low in organic matter and nutrient contents. The clay mineralogy of the soils is dominated by halloysite and kaolinite with minor amounts of goethite and hematite, and they also have generally high dithionite-extractable Fe contents confirming the advanced stage of their development. The soils in the more stable slope positions (PL-1, PL-2, and PL-4) have generally similar characteristics and appeared more developed than the one in the less stable position (PL-3). The most important pedogenic processes that formed the soils appear to be weathering, loss of bases and acidification, desilification, ferrugination, clay formation and translocation, and structure formation. The nature of the parent rock and climatic conditions prevailing in the area as well as slope position appear to have dominant effects on the development of the soils.     

Swell-dominant surface waves observed by a moored buoy with a GPS wave sensor in Otsuchi Bay,a ria in Sanriku,Japan

Real-time monitoring of wind and surface waves in Otsuchi Bay, Iwate, Tohoku, Japan, commenced in October 2012, using a mooring buoy with an ultrasonic anemometer and a single-mode GPS wave sensor. Wind and wave data are distributed hourly in real time via the Internet along with a chart of their time series. We analyzed data monitored in the first 3 months in order to assess the variability and occurrence of wind and waves and to elucidate the main reasons for wave variation in Otsuchi Bay. The monitoring data revealed that surface waves in the bay were predominantly affected by swells propagated from the northeastern offshore region and that the wave height was significantly correlated with the component of wind velocity toward Otsuchi Bay in the northeastern offshore region that faces the bay mouth. The offshore wind field was expected to provide information useful for predicting coastal waves in a ria bay in Sanriku such as Otsuchi Bay. However, it should be emphasized that the horizontal distribution of the offshore wind field which has a significant effect on the surface waves in a ria bay depends heavily on the topographic shape of the bay.     

New discoveries in dynamics of an M8 earthquake-phenomena and their implications from the 2003 Tokachi-oki earthquake using a long term monitoring cabled observatory

At the 2003 Tokachi-oki earthquake of M8, seafloor phenomena such as a generation process of tsunami, seafloor uplifts, turbidity current, etc., were observed using a cabled observatory installed on the seafloor. The turbidity current was observed as a benthic storm caused presumably by the mainshock. The seafloor uplifts were observed at the mainshock and continuously after the mainshock. The uplifts were 0.35, 0.37, and 0.12 m for epicentral distances of 25.5, 31.4, and 81.7 km, respectively. After the mainshock, a continuous uplift of the seafloor is observed at all three pressure gauge locations indicating that there was a change in the state of friction on the plate boundary interface by the mainshock. In this paper, we first show what was observed using the cabled observatory installed right above the focal area of the earthquake, and then we discuss to summarize these phenomena associated with the earthquake, its possible causes, and future directions in long term monitoring of seismogenic processes.     

The first three orders of scattering in vertically inhomogeneous scattering-absorbing media

In order to facilitate the computations of the intensities of radiation reflected and/or transmitted by plane-parallel, vertically inhomogenous, scattering-absorbing media, we carry out the optical thickness integrations of the Cauchy systems (normally referred to as Invariant Imbedding Equations) for reflection and transmission functions originating from the first three orders of scattering: the medium in question is represented by a stack of a certain number of homogeneous slabs, each of which is characterized by a constant single scattering albedo and a constant phase function together with the optical thickness.The results are a set of recurrence formulae involving only the angular intergrations, a convenient feature for numerical computations, and should prove useful particularly for finding approximate values of the high frequency Fourier coefficients of reflection and transmission functions of inhomogeneous media or efficiently initializing the solution for a thin layer to perform rigorous multiple scattering computations by means of other techniques such as the Doubling-Adding method.     

Automatic extraction of lineament information from satellite images using digital elevation data

Using conventional visual interpretation in lineament analysis presents two main problems. The first is subjectivity, introduced because of the bias of various interpreters. The second problem is that lineaments detected from satellite images are constrained by the direction of the illumination source. Since lineament identification mainly involves recognition of diagnostic morphological features, the use of digital elevation can contribute significant information about these features. Further, in generating images using digital elevation data, the direction of illumination can easily be controlled. Thus, the use of digital elevation data offers the possibility of revealing features not apparent in regular satellite images.We discuss a sequential line detection method for extraction of linear features from digital elevation data. In this method, raw elevation data is used for generating shaded relief images using the Lambertian reflection model, wherein the illumination direction is controlled by the user. The Directional Segment Detection Algorithm (DSDA) is used for detecting linear topographic features in user-defined trends. Locational information about these linear features is stored in the computer as coordinate pairs amenable to editing and subsequent analysis. Finally, three-dimensional terrain models are generated by combining the digital elevation data and satellite images. The experiments were carried out using digital elevation data of southwest Japan and Landsat MSS data.