July 2018

July, 2018   ||  Volume 22 No.4


On robust estimation of derivative of noisy dataset: Application on temperature gradient of ocean water column

Indrajit G. Roy
Spaceage Geoconsulting, 5 Bick Place, Banks, ACT 2906, Australia
Email: spaceage.geocon@gmail.com

We propose a simple technique of robust estimation of first order derivative of a discrete set of noisy measurements. The proposed technique uses conventional numerical tools, such as the first order finite difference and the natural cubic spline on evenly spaced noisy dataset and provides robust estimation of the first order derivative. We also propose simple techniques in estimating noise level in the measured data. This allows designing the estimated derivative dependent on the noise level in the measured data. We conducted numerical experiments using the proposed technique on synthetic data contaminated with random noise. Results from numerical experiment demonstrate applicability of the technique to the data contaminated with a moderate level of noise. We validate the proposed technique in estimating the temperature gradient of a water column from a set of noisy measurements of temperature versus depth at the northern Gulf of Mexico.
Key words: Finite difference, Cubic spline, Robust, Derivative.

Geophysical investigation for base metal mineralization in Karoi-Rajpura area, Bhilwara district, Rajasthan

D.C. Naskar*1, A.V. Kulkarni2, and M. Lakshmana1
*1 Southern Region, Geological Survey of India, Bandlaguda, Hyderabad-500068
2 Central Region, Geological Survey of India, Seminary Hills, Nagpur-440006
*Corresponding Author: dcnaskar@yahoo.com

Today, there is a challenge before geoscientists to discover new mineral deposits by an exploration technique, which should have low risk, consume less time and also cost effective. Towards reaching this goal, Geophysical methods with the phenomenal improvement in the design and development of equipment, methods and precision of data acquisition, processing and interpretation, play an indispensable role. A combination of SP, IP, Resistivity and Magnetic methods was attempted in Karoi-Rajpura area of Bhilwara District of Rajasthan for locating base metal occurrence. The integrated interpretation of the geophysical response of the different geophysical methods, revealed more precise information about the subsurface configuration and mineral distribution in the prospect area. Strong geophysical anomalies were observed in the northern, southern, central and eastern parts of the study area. The low resistivity zones (200 Ohm-m) and high chargeability zones (>24 mV/V) are situated in the southern and eastern parts of the investigated area. However, to strengthen the reliability of the results, the resistivity map is compared with chargeability map; those who have intersection area between low resistivity and high chargeability (> 24 mV/V), are considered to be the prospective zones of base metal mineralization. However, these low resistivity zones may have been influenced by the presence of clay or weathered soil. In this case, the high chargeability zones will help in confirming the prospective zones caused by base metal mineralization. Recent deep drilling by Hindustan Zinc Limited (HZL) in this area has intersected rich ore lodes, thereby confirming depth wise continuity of ore zones at some places.
Key words: Aravalli craton, Bhilwara Super Group, Polymetallic sulphide belt, Rajpura-Dariba Group.

Probabilistic Seismic Hazard Analysis for Jabalpur area,
Madhya Pradesh, India

G. Dhanunjaya Naidu*, S. Selvan, G.R.Tripathy and L.R.Pattanur
Central Water and Power Research Station, Khadakwasla, Pune-411024
*Corresponding Author: dhanugeo@gmail.com

The Jabalpur city, situated in seismically active Central Indian Tectonic Zone (CITZ), witnessed a major earthquake of Mw 5.8 on 21st May, 1997. It caused significant damage to the structures and loss of human lives in Jabalpur city and surrounding areas. This necessitated the estimation and quantification of future ground motion in the Jabalpur area for protecting the buildings, life line and other sensitive structures. State-of-art probabilistic seismic hazard analysis study was carried out, covering the Jabalpur city on a grid size of 0.01° x 0.01° to develop seismic hazard maps of the city. Suitable Ground Motion Prediction Equation (GMPE) is used for reliable estimation of seismic hazard by considering the effects of all the earthquakes of different magnitudes and their spatial distribution. Seismic events of different magnitudes within the radius of 300 km from the Jabalpur city as center are considered for analysis. Peak Ground Acceleration (PGA) and spectral amplitudes at 0.2 sec and 1sec are estimated at each grid point, thereby, generating seismic hazard maps for Jabalpur city for the return periods of 2475 (~2500) and 475 (~500) years with 5% damping. The results highlight the surface level seismic hazard within the city.
Key words: Seismic hazard, probabilistic seismic hazard analysis, attenuation, Peak ground acceleration, ground motion prediction equation.

Geomorphic Expressions of Active Strike-slip faulting (Girnar Fault), Saurashtra, Western India

Tarun Solanki*1, S. P. Prizomwala1, and P. M. Solanki2
1Active Tectonics Group, Institute of Seismological Research, Gandhinagar, India 382009
2Department of Geology, M. G. Science Institute, Navrangpura, Ahmedabad 380009
* Corresponding Author: tarunsolanki86@yahoo.in  

The Talala region of Saurashtra in Western India has been rocked by three moderate seismic events of Mw 4.8 (2007), Mw 5.0 (2007) and Mw 5.1 (2011). Despite several seismological observation, which hint at monsoon, triggered earthquake activity responsible for swarm type activity, the moderate events may have another causal mechanism. There is limited data available pertaining to geomorphic / surface expression of faults in the region, which is crucial for understanding the crustal deformation going on in this seismically active intraplate region. In present paper, we report the geomorphic evidences of active left-lateral strike-slip movement with presence of oblique slip component along a fault (Girnar Fault). The zone of the fault extends for about 60 km in length in NE-SW direction, nevertheless the seismological observations suggests seismicity is only restricted to a length of 40 km. The drainage network of Hiren and Shetrunji rivers show anomalous pattern inform of offset channel, deflected streams and straight channels, which are characteristic signatures of strike-slip faulting, apart from aligned drainages and linear valleys. Unpaired terraces presence in the study area indicates presence of dip slip component along the fault. Our results suggest, factors other than monsoon-triggered seismicity, are also present and active in the region, which might have played a role in causing moderate earthquakes.
Key words: Strike slip fault, Girnar Fault, Intraplate earthquake, Saurashtra, Geomorphic anomaly.

Drainage Basin Morphometric Analysis of Mountain-Plain (Kosi, Bihar) and Plateau-plain (Kangsabati, WB) Regions of Tropical Environment: A Comparative Analysis

Avijit Mahala
Centre for the study of Regional Development, Jawaharlal Nehru University, New Delhi, India, 110067.
E-mail: mahala.avijit@gmail.com

Morphometric analysis is an important indicator to understand the geomorphic, geologic, hydrological and evolutionary characteristics of any region. In this study, morphometric analysis has been carried out to compare the drainage basin characteristics of mountain-plain and plateau-plain region of tropical India. The Kosi basin of the mountain-plain area and Kangsabati basin of the plateau-plain area, are selected for the present study. The geological, geomorphological, hydrological, fluvial characteristics have been traced from different morphometric parameters for these two different morpho-climatic settings. Different drainage morphometric parameters and measurements related to linear, areal, and relief characteristics have been determined through Shuttle Radar Topography Mission (SRTM GDEM, 90m.) and ARC GIS 10.1. The mean Bifurcation ratio indicates that Kosi has greater flood potentiality than Kangsabati Basin. Kosi carries large amount of water due to its near-circular basin shape, compared to Kangsabati basin which has an elongated shape. All the relief characteristics indicate that the Kosi basin is rejuvenated or at the young stage of geomorphic development, than the mature Kangsabati River basin of plateau region. Most of the morphometric characteristics indicate that there are high geologic and geomorphological controls on river basin characteristics.
Key words: Evolutionary characteristics, Tropical India, Fluvial characteristics, Kosi Basin, Kangsabati basin, Morpho-climatic settings, Relief characteristics, SRTM, Geomorphic development..

The observational case study of total columnar ozone associated with meteorological synoptic conditions over the Indian peninsular station

M.N. Patil*, G.S. Meena, G. R. Chinthalu, T. Dharmaraj and Devendraa Siingh
Indian Institute of Tropical Meteorology, Pune - 411008, India
*Corresponding Author: patil@tropmet.res.in

The Total Columnar Ozone (TCO3) was measured over the rural site of Mahabubnagar of south India, as a part of Cloud Aerosol Interaction and Precipitation Enhancement Experiment – Integrated Ground Observations Campaign (CAIPEEX-IGOC), during October-November 2011. Along with TCO3, the collocated high resolution profiles of air temperature, water vapor and wind speed up to mid-stratosphere (~ 30 km) was also obtained by GPS Sonde. The TCO3 variations show higher amount of TCO3 in the morning hrs than that of evening hrs. Also a sudden reduction of TCO3 of the order of 100 - 110 DU in 12 h time scale was observed.
Key words: Total column ozone, cyclonic storm, Atmospheric chemistry, Atmospheric electricity, CAIPEEX..

Estimation of Dar-Zarrouk parameters for groundwater exploration in parts of Chopda Taluka, Jalgaon district, Maharashtra (India)

S.N. Patil, N.R. Kachate*, and S.T. Ingle
School of Environmental and Earth Sciences, North Maharashtra University, Jalgaon, Maharashtra.
*Corresponding Author: kachatenandkishor@gmail.com

Vertical Electrical Soundings using Schlumberger technique with a maximum current electrode spacing (AB/2) of 150 m were carried out at 34 locations to delineate the ground water potential zones in Chopda taluka of Jalgaon district (Maharashtra), covered by Deccan trap inliers in the center surrounded by alluvium. The results indicate that the study area encompasses a multilayer admixture of pebbles, sand, silt and clay, with resistivity values in the range of 18-25 Ω-m. The area comprised of three types of aquifers which is (i) loose clayey or silt with intercalation of sand (< 10 Ω-m), (ii) clayey-sand layer (10-25 Ω-m), and (iii) compacted clay or pebbles/cobbles and sand (25-50 Ω-m). VES 29 and 15 inliers, are seemingly composed of fractured and weathered basaltic formation. Hard rock is revealed at 12-25 m and exposed at some locations in Chahardi area. Four resistivity profiles revealed a clear picture of the continuity of aquifer and movement of water, while the sounding data provided 2-5 geoelectric layers of different thickness. Dar-Zarrouk parameters i.e., (i) Longitudinal conductance (S) (ii) Longitudinal resistivity (ρl) (iii) Transverse resistance (T) (iv) Transverse resistivity (ρt) and (v) Electrical anisotropy (λ), derived from resistivity data helped in categorizing the study area with respect to protective capacity rating of different aquifers. The S map suggest that about 17 % of the area falls under ‘very good’ to ‘excellent’ and protective capacity, while about 50 % falls under ‘good’ protective capacity rating. A large variation is observed in λ map, ranging from 0.38 to 2.73 over the studied region. This indicates the anisotropic nature of the aquifers in such hard rock terrain. Several lineaments are cris-crossing the study area and the intersection points are considered favorable zone for groundwater exploration.
Key words: Vertical Electrical Sounding, Alluvium, Dar Zarrouk parameters, Longitudinal conductance.

Assessment of urban pollution from heavy metals concentration in road dust in Greater Hyderabad Municipal Corporation (GHMC), Telangana State, India.

R.Sudarshan1, B.Madhusudan Rao1*, B.Nagaraju1, S.K.Patil2, K.Lohith kumar3 
1Centre of Exploration Geophysics, Osmania University, Hyderabad, Telangana State, India.
2K.S.Krishnan Geomagnetic Laboratory (KSKGRL) Allahabad, India.
3 CSIR-National Geophysical Research Institute (NGRI), Hyderabad, India.
*Corresponding Author: profmadhurao@gmail.com

Greater Hyderabad Municipal Corporation (GHMC) is witnessing fast urbanization characterized by rapid urban sprawl, population growth, infrastructural construction, industrialization and motorization, which is leading to environmental degradation, placing human health at risk. Presently, heavy metals in road dusts are used as proxies to illustrate environmental changes of GHMC area. In this study 307 dust samples were collected along the roads of GHMC in one season of the year 2014.Further, measurements like Magnetic susceptibility(χ), Anhysteretic remanent magnetization (ARM) and Isothermal Remanent Magnetization (IRM), on these samples have revealed high concentration of magnetic minerals like magnetite and hematite in the urban road dust. The results indicate increasing trends, though not steady, in traffic and industry contributed pollution. Regular measurement and monitoring of these pollution markers in different seasons and for longer periods can help understand area-wise ill-effects of the present trend of urbanization and therefore guide the city planners and rulers.
Key words: Environmental Magnetism, Urbanization, Traffic, Road dust, GHMC.

Preliminary ground based measurements of Aerosol Optical thickness over Udaipur (Rajasthan), India

Roshni Dave*1 and Malini Aggarwal2
1Department of Physics, Silver Oak College of Engineering &Technology, Ahmedabad, India, 382481
2Indian Institute of Geomagnetism, Navi Mumbai, India, 410206
*Corresponding Author: roshnidave.gn@socet.edu.in

We have carried out studies to understand the variability of Aerosol Optical Thickness (AOT) and precipitable water-vapour content (PWC) over Udaipur (24.58°N, 73.71°E), using hand-held microprocessor based MICROTOPS sun photometer-540 (1020 nm and 936 nm) from February, 2002 to March, 2004, excluding the rainy days (total of 156 days of clear-sky observations). We found that monthly AOT varied between 0.16 and 0.54 during the whole period and was higher in summer (mean value ~0.32) than the winter months (mean value ~0.19) with highest value in pre-monsoon month of June (0.54). The day-to-day variability of AOT is also higher in summer than winter months and is lowest during the post-monsoon months. We also found PWC to be maximum in monsoon month (July, ~3 cm) and minimum in December-February (~0.5 cm) winter months. A positive moderate correlation (0.45) between monthly AOT and PWC over the station during the study period is reported. This suggests that the production and loss of aerosol particles, which are hygroscopic in nature, are also associated with precipitable water-vapour content along with the other meterological factors.
Key words: Aerosol, Climate, precipitable water-vapour, atmosphere..

Study and analysis of weather parameters during avalanche for Bahang region, Manali (Himachal Pradesh)

Neha Ajit Kushe* and Ganesh M. Magar
P.G. Department of Computer Science, S.N.D.T. Women’s University, Juhu Road, Mumbai-49
*Corresponding Author: neha.kushe@hotmail.com

Snow avalanche has been an integral part of the natural hazards in the mountainous region. In India, avalanches are mainly observed in the north and north-eastern zone of the country, which mainly comprises of Himalayas and their surrounding areas. The Himalayan region is broadly classified into Upper, Middle and Lower Himalaya Zones. However, due to the varied nature of meteorological and environmental conditions, the avalanche climatology is not the same for the whole Himalayan range and the environmental factors that lead to avalanche in all these zones, are different. This paper presents the study and analysis of the weather parameters during avalanche, to find influencing range of the weather parameters for avalanche occurrence in Bahang region of Manali, Himachal Pradesh, which falls in the Lower Himalaya Zone.
Keywords: Avalanche, Bahang region, Himalayas, Meteorological parameters, Snow..