Buried and Submerged Greek Archaeological Coastal Structures and Artifacts as Gauges to Measure Late Holocene Seafloor Subsidence off Calabria,Italy

This synthesis integrates recently acquired archaeological and geological data with earlier documented observations to shed light on the subsidence of ancient Greek coastal facilities in southern Italy. These are now positioned between former shorelines and inner shelf sectors at five Calabrian margin localities. Submergence of coastal to inner shelf facilities has resulted in part from sea‐level rise by about 2 m associated with glacio‐hydro‐isostatic factors since archaic to classic Greek time. This phenomenon alone, however, does not explain the wide variation of measured subsidence rates from site‐to‐site. The marked lowering of coastal site substrates by seismo‐tectonic activity (including extensional fault motion), stratal readjustments at depth, and compaction of underlying sediment sequences is significant. Four of the subsided facilities are positioned near emerged Calabrian areas where prevailing Holocene average annual land uplift rates range to ˜1.0 mm/yr; at the fifth, near Hipponion, terrains have risen by nearly 2 mm/yr. In marked contrast, submerged and/or buried structures record the following late Holocene long‐term average rates of coastal margin subsidence: Sybaris‐Thuri on the Taranto Gulf margin (˜0.5–1.0 mm/yr); Hipponion‐Vibo Valentia along the Tyrrhenian coast (˜0.8 to ˜3.2 mm/yr); and Locri‐Epizefiri, Kaulonia, and Capo Colonna on Calabria's Ionian margin (˜1.6, ˜1.6–2.4, and ˜4.0 mm/yr, respectively). © 2012 Wiley Periodicals, Inc.     

Coastal water pollution in two rivers of the Bengal delta

A thorough comprehension of relevant environmental parameters is a prerequisite to preventing coastal degradation and environmental balance in coastal zones. In this study, we correlate major physicochemical of two coastal rivers (Matla and Saptamukhi) in the Sunderban district, West Bengal. The parameters namely: pH, salinity, dissolved oxygen, suspended solids, nitrogen and phosphorus concentrations (inorganic and total) of these two rivers were studied in detail over the 90s decade. We hypothesized that both natural and anthropogenic activities during that time have contributed to the pollution and employed the above parameters to test our hypothesis. Our results reveal that the quality of waters in the rivers have been showed to be dependent on flood impacts, storm surge, eutrophication, domestic sewage, agricultural and industrial wastes. Thus, both natural and anthropogenic causes are the behind coastal pollution of river waters. We conclude that they have all contributed to pollution of these rivers in various ways and we calculate the differential effects of these parameters on coastal pollution.     

Implications of channel flow analogue models for extrusion of the Higher Himalayan Shear Zone with special reference to the out-of-sequence thrusting

The Higher Himalayan Shear Zone (HHSZ) contains a ductile top-to-N/NE shear zone—the South Tibetan detachment system-lower (STDS_L) and an out-of-sequence thrust (OOST) as well as a top-to-N/NE normal shear at its northern boundary and ubiquitously distributed compressional top-to-S/SW shear throughout the shear zone. The OOST that was active between 22 Ma and the Holocene, varies in thickness from 50 m to 6 km and in throw from 1.4 to 20 km. Channel flow analogue models of this structural geology were performed in this work. A Newtonian viscous polymer (PDMS) was pushed through a horizontal channel leading to an inclined channel with parallel and upward-diverging boundaries analogous to the HHSZ and allowed to extrude to the free surface. A top-to-N/NE shear zone equivalent to the STDS_U developed spontaneously. This also indirectly connotes an independent flow confined to the southern part of the HHSZ gave rise to the STDS_L. The PDMS originally inside the horizontal channel extruded at a faster rate through the upper part of the inclined channel. The lower boundary of this faster PDMS defined the OOST. The model OOST originated at the corner and reached the vent at positions similar to the natural prototype some time after the channel flow began. The genesis of the OOST seems to be unrelated to any rheologic contrast or climatic effects. Profound variations in the flow parameters along the HHSZ and the extrusive force probably resulted in variations in the timing, location, thickness and slip parameters of the OOST. Variation in pressure gradient within the model horizontal channel, however, could not be matched with the natural prototype. Channel flow alone presumably did not result in southward propagation of deformation in the Himalaya.     

Evaluating a thermal image sharpening model over a mixed agricultural landscape in India

Fine spatial resolution (e.g., <300 m) thermal data are needed regularly to characterise the temporal pattern of surface moisture status, water stress, and to forecast agriculture drought and famine. However, current optical sensors do not provide frequent thermal data at a fine spatial resolution. The TsHARP model provides a possibility to generate fine spatial resolution thermal data from coarse spatial resolution (≥1 km) data on the basis of an anticipated inverse linear relationship between the normalised difference vegetation index (NDVI) at fine spatial resolution and land surface temperature at coarse spatial resolution. The current study utilised the TsHARP model over a mixed agricultural landscape in the northern part of India. Five variants of the model were analysed, including the original model, for their efficiency. Those five variants were the global model (original); the resolution-adjusted global model; the piecewise regression model; the stratified model; and the local model. The models were first evaluated using Advanced Space-borne Thermal Emission Reflection Radiometer (ASTER) thermal data (90 m) aggregated to the following spatial resolutions: 180 m, 270 m, 450 m, 630 m, 810 m and 990 m. Although sharpening was undertaken for spatial resolutions from 990 m to 90 m, root mean square error (RMSE) of <2 K could, on average, be achieved only for 990–270 m in the ASTER data. The RMSE of the sharpened images at 270 m, using ASTER data, from the global, resolution-adjusted global, piecewise regression, stratification and local models were 1.91, 1.89, 1.96, 1.91, 1.70 K, respectively. The global model, resolution-adjusted global model and local model yielded higher accuracy, and were applied to sharpen MODIS thermal data (1 km) to the target spatial resolutions. Aggregated ASTER thermal data were considered as a reference at the respective target spatial resolutions to assess the prediction results from MODIS data. The RMSE of the predicted sharpened image from MODIS using the global, resolution-adjusted global and local models at 250 m were 3.08, 2.92 and 1.98 K, respectively. The local model consistently led to more accurate sharpened predictions by comparison to other variants.     

Quantitative modeling of groundwater in Satluj River basin of Rupnagar district of Punjab using remote sensing and geographic information system

Water is a fluctuating resource making it difficult to measure in time and in space. To demonstrate the efficiency of the geographic information system (GIS) for groundwater studies, information on the parameters controlling groundwater such as lithology, geomorphology and lineament analysis were analyzed. LISS-III and Landsat satellite image of the area was used to infer information on the geologic lineaments and geomorphology. To delineate linear features enhancement and direction, filtering was performed on single bands of Landsat images. Thematic maps for geology, slope, geomorphology and lineament were prepared and integrated in GIS by assigning the weights and ranking to various parameters controlling the occurrence of groundwater to generate the groundwater potential map for the study area. The results indicate that the floodplain of river and its adjoining areas have very good groundwater potential, whereas the steeply sloping area in the northern part having high relief and slope possesses poor groundwater potential.     

Viscous dissipation pattern in incompressible Newtonian simple shear zones: an analytical model

An analytical model of shear heating in an inclined simple shear zone with Newtonian rheology under a reverse shear sense and an upward resultant pressure gradient is presented. Neglecting a number of secondary factors, the shear heat is expressed as a function of the total slip rates at the boundaries, pressure gradient, dip and thickness of the shear zone, and density, viscosity, and thermal conductivity of the rock. A quartic temperature profile develops with a point of maximum temperature near the bottom part of the shear zone in general. The profile is parabolic if pressure gradient vanishes leading to a Couette flow. The profile attains a bell shape if there is no slip at the boundaries, i.e., a true Pouseille flow. The present model of shear heating is more applicable in subduction channels and some extruding salt diapirs where the rheology is Newtonian viscous and pressure gradient drives extrusion.     

Channel flow extrusion model to constrain dynamic viscosity and Prandtl number of the Higher Himalayan Shear Zone

Constraining magnitudes of mechanical and thermo-mechanical parameters of rocks and shear zones are the important goals in structural geology and tectonics (Talbot in J Struct Geol 21:949–957, 1999). Such parameters aid dynamic scaling of analogue tectonic models (Ramberg in Gravity, deformation and the Earth’s crust in theory, experiments and geological applications, 2nd edn. Academic Press, London, 1981), which are useful to unravel tectonics in further details (Schultz-Ela and Walsh in J Struct Geol 24:247–275, 2002). The channel flow extrusion of the Higher Himalayan Shear Zone (HHSZ, = Higher Himalaya) can be explained by a top-to-S/SW simple shear (i.e. the D₂ deformation) in combination with a pressure gradient induced flow against gravity. Presuming its Newtonian incompressible rheology with parallel inclined boundaries, the viscosity (μ) of this shear zone along a part of the Himalayan chain through India, Nepal and Bhutan is estimated to vary widely between ~10¹⁶ and 10²³ Pa s, and its Prandtl number (P _r ) within ~10²¹–10²⁸. The estimates utilized ranges of known thickness (6–58 km) of the HHSZ, that of its top subzone of ductile shear of normal shear sense (STDS_U: 0.35–9.4 km), total rate of slip of its two boundaries (0.7–131 mm year^?1), pressure gradient (0.02–6 kb km^?1), density (2.2–3.1 g cm^?3) and thermal diffusivity (0.5 × 10^?6–2.1 × 10^?6 m s^?2) along the orogenic trend. Considering most of the parameters specifically for the Sutlej section (India), the calculated viscosity (μ) and the Prandtl number (P _r ) of the HHSZ are deduced to be μ: ~10¹⁷–10²³ Pa s and P _r  ~ 10²²–10²⁸. The upper limits of the estimated viscosity ranges are broadly in conformity with a strong Tibetan mid-crust from where a part of the HHSZ rocks extruded. On the other hand, their complete ranges match with those for its constituent main rock types and partly with those for the superstructure and the infrastructure. The estimated mechanical and thermo-mechanical parameters of the HHSZ will help to build dynamically scaled analogue models for the Himalayan deformation of the D₂–phase.     

Geochemical modelling, ionic ratio and GIS based mapping of groundwater salinity and assessment of governing processes in Northern Gujarat, India

In semi-arid/arid regions, groundwater is the major source of irrigation, drinking and industrial requirements, water salinity and shortage are major problems of concern. North Gujarat, India, is one such area where highly saline groundwater is generally ascribed to rapid increase of population, agriculture and industries induced decline in water table by unplanned abstraction of groundwater. However, no effort has been made to discriminate the natural and anthropogenic influences on groundwater salinity. In this brief background, the present study attempts to identify the factors and processes controlling the groundwater salinity in the area, based on ionic ratios in integration with various graphical methods, saturation indices and geographical information system. Na⁺/Ca²⁺ > 1 indicates the deficiency of Ca²⁺ possibly due to CaCO₃ precipitation or ion exchange process. Na⁺/Cl^? > 1 and $ {\text{SO}}_{4}{}^{2 - } /{\text{Cl}}^{ - } \gg 0.05 $ suggest salinization is mainly due to wastewater infiltration and/or due to irrigation water return flow. Sea water intrusion in coastal parts, vertical and lateral mixing of water and anthropogenic inputs are also responsible for salinization of groundwater. USSL diagram, Na%, sodium adsorption ratio, residual sodium carbonate and magnesium hazard indicate unsuitability of groundwater for irrigation purposes. To prevent groundwater salinization, appropriate measures need to be taken to control further indiscriminate exploitation of groundwater for irrigation.     

Reproducing the Piper trilinear diagram in rectangular coordinates

Though several alternatives/modifications to the Piper diagram are available, the Piper diagram is still the most common way of representing chemical analyses. The present note shows how to reproduce the Piper trilinear diagram in rectangular coordinates retaining all the essential features of the trilinear diagram. In this form, it can be generated using commonly used graphics packages without requiring specialized software. A sample data set of six samples from Gurur watershed, Chhattisgarh, India, was used to illustrate the method. The patterns of points produced in the trilinear Piper diagram and the reproduced Piper diagram in rectangular coordinates are essentially identical.