This document provides an overview of various groundwater exploration methods, including surface and subsurface techniques. Surface methods involve minimal facilities and include geomorphological analysis of landforms, geological and structural mapping, soil and vegetation analysis, remote sensing, and surface geophysical methods like electrical resistivity and seismic surveys. Subsurface methods like borehole logging and test drilling provide direct observations but are more expensive. Together, a multi-method approach can be used to explore groundwater resources and locate potential zones for development.
Groundwater province is an area or region in which geology and climate combine to produce groundwater conditions consistent enough to permit useful generalisations.
Groundwater province is an area or region in which geology and climate combine to produce groundwater conditions consistent enough to permit useful generalisations.
The subsurface occurrence of groundwater may be divided into zones of aeration and saturation. The vertical distribution of groundwater is explained in this module.
Types of dams, geological considerations in site selection, Competency of Rocks to offer stable dam foundation, effect of geological structures on dam, selection of dam site, Reservoir, purpose of reservoir, influence of water table, geological structures, life of reservoir, geophysical studies
It covers seismic method, gravity method, electromagnetic method, magnetic method and radiometric method. all these methods help in mineral exploration
It includes the definition, properties, classification of groundwater with appropriate examples and figures in details. It also deals about the formation of groundwater. The properties of aquifers (all of 7) are described here in details with figures and mathematical terms.
Sea Water Intrusion(SWI) in coastal areas :
1. Occurrence of seawater intrusion
2.Factors that affect coastal aquifer
3.Changes by hydrological regime
4.Problems due to SWI
5.Ghyben-Herzberg relation
6.Methods to detect SWI
7.Control measures
Over the last decade, demand for spring management has increased as traditional spring sources have started drying up or becoming contaminated. In response, communities, NGOs and state agencies began dedicated spring protection programmes. In the Himalayas, the State of Sikkim and organizations such as Central Himalayan Action and Research Group (CHIRAG) and People Science Institute (PSI) started identifying and protecting spring recharge areas around 2007. The difference between these programmes and many other previous efforts is that they went beyond supply-side improvements to focus on the use of hydrogeology to map springsheds for targeted interventions.
The Advanced Centre for Water Resources Development and Management (ACWADAM), a research and capacity-building organization comprised of hydrogeologists and other experts began lending their expertise and building capacity of stakeholders. ACWADAM provides technical support, training and materials in hydrogeology to all network partners as well as others in India and the region. Similar programmes began independently in most of the mountain regions of India. Arghyam, a funding organization that was supporting many of these programmes, noticed that these disparate initiatives shared commonalities despite geographic diversity. They thus organized and funded a meeting of these various organizations in June 2014, and the Springs Initiative was born.
The springs initiative aims to tackle the current water crisis and to ensure safe and sustainable access to water for all, by promoting responsible and appropriate management of aquifers, springsheds, and watersheds and conserving ecosystems in partnership with communities, governments and other stakeholders.
This presentation has been developed as a part of the springs initiative to promote an understanding of springs and their role in mountainous areas.
Rock Mass Classification and also a brief description of Rock Mass Rating (RMR), Rock Structure Rating (RSR), Q valves and New Austrian Tunneling method(NATM)
The subsurface occurrence of groundwater may be divided into zones of aeration and saturation. The vertical distribution of groundwater is explained in this module.
Types of dams, geological considerations in site selection, Competency of Rocks to offer stable dam foundation, effect of geological structures on dam, selection of dam site, Reservoir, purpose of reservoir, influence of water table, geological structures, life of reservoir, geophysical studies
It covers seismic method, gravity method, electromagnetic method, magnetic method and radiometric method. all these methods help in mineral exploration
It includes the definition, properties, classification of groundwater with appropriate examples and figures in details. It also deals about the formation of groundwater. The properties of aquifers (all of 7) are described here in details with figures and mathematical terms.
Sea Water Intrusion(SWI) in coastal areas :
1. Occurrence of seawater intrusion
2.Factors that affect coastal aquifer
3.Changes by hydrological regime
4.Problems due to SWI
5.Ghyben-Herzberg relation
6.Methods to detect SWI
7.Control measures
Over the last decade, demand for spring management has increased as traditional spring sources have started drying up or becoming contaminated. In response, communities, NGOs and state agencies began dedicated spring protection programmes. In the Himalayas, the State of Sikkim and organizations such as Central Himalayan Action and Research Group (CHIRAG) and People Science Institute (PSI) started identifying and protecting spring recharge areas around 2007. The difference between these programmes and many other previous efforts is that they went beyond supply-side improvements to focus on the use of hydrogeology to map springsheds for targeted interventions.
The Advanced Centre for Water Resources Development and Management (ACWADAM), a research and capacity-building organization comprised of hydrogeologists and other experts began lending their expertise and building capacity of stakeholders. ACWADAM provides technical support, training and materials in hydrogeology to all network partners as well as others in India and the region. Similar programmes began independently in most of the mountain regions of India. Arghyam, a funding organization that was supporting many of these programmes, noticed that these disparate initiatives shared commonalities despite geographic diversity. They thus organized and funded a meeting of these various organizations in June 2014, and the Springs Initiative was born.
The springs initiative aims to tackle the current water crisis and to ensure safe and sustainable access to water for all, by promoting responsible and appropriate management of aquifers, springsheds, and watersheds and conserving ecosystems in partnership with communities, governments and other stakeholders.
This presentation has been developed as a part of the springs initiative to promote an understanding of springs and their role in mountainous areas.
Rock Mass Classification and also a brief description of Rock Mass Rating (RMR), Rock Structure Rating (RSR), Q valves and New Austrian Tunneling method(NATM)
GROUND WATER RECHARGE TECHNIQUES BY CH.APPARAO (Research Associate, ARS, ATP)Apparao Chodisetti
Ground water recharge is the process whereby the amount of water present in or flowing through the interstices of the sub-soil increases by natural or artificial means. Rainfall is the principal source for replenishment of recharge of ground water. Other sources include recharge from rivers, streams, irrigation water etc. An unconfined aquifer is recharged directly by local rainfall, rivers, and lakes, and the rate of recharge will be influenced by the permeability of overlying rocks and soils. A confined aquifer, on the other hand, is characterized by an overlying bed that is impermeable, and local rainfall does not influence the aquifer. It is normally recharged from lakes, rivers, and rainfall that may occur at distances ranging from a few kilometers to thousands of kilometers.
is one of the first steps in
searching for oil and gas resources that directly
affects the land and the landowners Seismic surveys are like sonar on steroids They are based on recording the time it takes for sound waves generated by controlled energy sources .The survey usually requires people and machinery
to be on private property and may result in
disturbances of the land such as the clearing of
trees
Sources of groundwater pollution
Landfills: filling of the land pits which causes leaching of chemicals.
Industrial spills and waste disposal: industrial dumping in open areas and rivers.
Groundwater Quality from Basaltic Aquifers, Dr. S. K. Vadagbalkar, Associat...SHRINIVAS VADAGBALKAR
Basaltic aquifers-shallow and deep, from Deccan Trap regions in parts of Maharashtra state, are considered as a case study to understand the quality of waters. Based on the research articles, news, from scientific journals, reports of government and non-government social organisations, communications, newspaper articles and news, attempts have been made to prepare a concise reconnaissance review article.
Analysis of Microstructural Properties of Pliocene Aquifer in the Benin Forma...IOSR Journals
Aquifer microstructural properties were determined using grain size distribution data obtained from
core samples collected during a drilled water borehole. The core samples were collected at depths between 50-
152ft (21.5-65.4 m), corresponding to the aquifer repositories. Samples were oven dried at 800 C for 2hrs. Part
of the samples was used to obtain porosity for aquifer material, while the other part was analyzed mechanically
for particulate size distributions. The effective particulate size distributions at d10, d20 and d60 were obtained and
used to compute the aquifer uniformity coefficient (Cu).The effective particulate size distributions complemented
by eight empirical formulae were deployed to determine hydraulic conductivity of the aquifer. The ratio of the
horizontal hydraulic conductivity to vertical hydraulic conductivity yielded anisotropy values for the aquifer.
Results show that fractional porosity values ranged from 0.282 to 0.492; uniformity coefficient was between 2.5
and 12; horizontal hydraulic conductivity ranged between 0.343 and 2.511 m/day while the vertical hydraulic
conductivity values obtained ranged from 1.320 to 2.907 day/m. Anisotropy values (Av) determined for the
aquifer ranged between 0.118 and 1.005. These results suggest that the aquifer is of gravelly sand within the
deltaic deposit with no clay intercalation and has good potential for groundwater resources.
Impact of A Paleochannel on Hydrogeochemistry of A Quaternary Aquifer: Case S...QUESTJOURNAL
ABSTRACT: This study investigated the influence of Wadi Lamhah paleochannel on hydrogeochemistry of the Quaternary aquifer in Umm Al Quwain area, United Arab Emirates (UAE). Results show that the groundwater temperature in water wells affected by Wadi Lamhah channel was 3 to 7°C less than the groundwater temperature in rest of the study area. Groundwater salinity in the channel-affected wells ranged from 803 to 5,407 mg/L and averaged 3,219 mg/L, while the groundwater salinity in rest of the study area was higher, reaching 11,643 mg/L in well 24, which suffered from salt-water intrusion from the sea. Except HCO3 - (329 mg/L), average concentrations of major ions in the channel-controlled wells were lower than their average concentrations in all wells within the study area. Average concentrations of detected trace elements B, Fe and Zn were lower in channel-affected wells than the rest of the study area. The high total hardness in channelaffected wells reflected the flux of Ca and Mg-rich recharge water moving into the aquifer through its southern boundary. The calculated SAR values indicated that the groundwater is good for irrigation along the course of Wadi Lamhah channel and harmful to plant and soil in the rest of the study area.
CH7.1.pptx: ground water hydrolog of ethiymulugeta48
The annual amount of rain falls runoff is estimated around 122 billion m³ of water.
Groundwater resources are estimated around 36 billion m³.
In Ethiopia, some 80% to 90% of water resources are found in the basins of large rivers such as the Abay (Blue Nile), the Tekeze, the Baro Akobo and the Omo Gibe.
1. Ground Water Occurrence
2. Types of Aquifers
3. Aquifer Parameters
4. Darcy’s Law
5. Measurement of Coefficient of Permeability of Soil
6. Types of Wells
7. Well Construction
8. Well Development
E-content is a Comprehensive package of teaching material put into hypermedia format. Hypermedia is multimedia with internet deplorability. E-content can not be created by a teaching faculty alone . It needs the role of teacher, Video editor, production assistants, web developers (HTML 5 or Adobe captivate, etc). Analyze the learner needs and goals of the instructional material development, development of a delivery system and content, pilot study of the material developed, implementation, evaluating, refining the materials etc. In designing and development of E-content we have to adopt one of the instructional design models based on our requirements.
Pedagogy is the most commonly understood approach to teaching. It refers to the theory and practice of learning. Pedagogy is often described as the act of teaching. Pedagogy has little variations between traditional teaching and online teaching. Online teaching pedagogy is a method of effective teaching practice specifically developed for teaching via the internet. It has a set of prescribed methods, strategies, and practices for teaching academic subjects in an online (or blended) environment, where students are in a physical location separate from the faculty member.
Technology has changed the possibilities within teaching and learning. Classes, which prior to the digital era were restricted to lectures, talks, and physical objects, no longer have to be designed in that manner. Training in a synchronous virtual classroom can only be successful with the active participation and engagement of the learners. Explore the Virtual Classroom’s features and see how they can support and enhance your tutoring style.
• The monitoring and evaluation of the institutional processes require a carefully structured system of internal and external review. The NAAC expects the Institutions to undertake continuous Academic and Administrative Audits (AAA). This presentation is intended to serve as advisory to all accredited HEIs who volunteer to undertake AAA. The pros and cons of this process are also highlighted. Academic and Administrative Audit is the process of evaluating the efficiency and effectiveness of the administrative procedure. It includes assessment of policies, strategies & functions of the various administrative departments, control of the overall administrative system, etc. This checklist gives an overview what the audit committee members may look into while visiting an institution for this purpose. It invariably follows the Quality Indicators Framework prescribed by Accreditation Council in India.
• The monitoring and evaluation of the institutional processes require a carefully structured system of internal and external review. The NAAC expects the Institutions to undertake continuous Academic and Administrative Audits (AAA). This presentation is intended to serve as advisory to all accredited HEIs who volunteer to undertake AAA.
Chemical analysis data of water samples can not be used directly for understanding. They are to be used for various calculations in order to determine the quality parameters that have a lot of significances. A. Balasubramanian and D. Nagaraju, of the Department of Studies in Earth Science, Centre for Advanced Studies, University of Mysore, Mysore-570006, Karnataka, India have recently brought out a software and its application manual as a good book for reference and execution. The Name of the software is WATCHIT meaning Water Chemistry Interpretation Techniques. This software computes more than 100 parameters pertaining to water quality interpretations. The software follows its own method of approach to determine the required results. Systems International Units are used. Limited input parameters are required. This is suitable for all scientific research, government water quality data interpretations and for understanding the quality of water before using it.
Water conservation refers to reducing the usage of water and recycling of waste water for different purposes like domestic usage, industries, agriculture etc. This technical article highlights most of the popular methods of water conservation. A special note on rainwater harvesting is also provided.
This module gives an overview of general applications of current hydrogeological aspects. It is for the basic understanding of students and research scholars.
Climate Extreme (extreme weather or climate event) refers to the occurrence of a value of a weather or climate variable above (or below) a threshold value near the upper (or lower) ends of the range of observed values of the variable. Extreme weather and climate events, interacting with exposed and vulnerable human and natural systems, can lead to disasters.
WATER RESOURCES PLANNING AND MANAGEMENT POSSIBILITIES IN CHAMARAJANAGAR TALUK...Prof. A.Balasubramanian
Any unplanned development and utilization of water resources with result in water scarcity. In many parts of the developing world. Such a situation exists. In order to do proper planning and
management of water resources, it is necessary to conduct detailed analyses of the factors, which influence the water availability and its uses. In the present study, a comprehensive analysis have been undertaken for proper utilization of water resources in Chamarajanagar Taluk, which has been identified as one of the drought hit districts of Karnataka, in India. The factors analysed in this work are, surface and groundwater availability, land use, cropping pattern, recharge potential of soils and the rainfall pattern in typical areas of Taluk. It is observed that the problem of water scarcity is mainly due to the lack of irrigation planning and management. Hence, a
modified cropping pattern is suggested by taking into consideration of all available water resources and other conditions.
In broad terms, cultural geography examines the cultural values, practices, discursive and material expressions and artefacts of people, the cultural diversity and plurality of society.
It also emphasizes on how cultures are distributed over space, how places and identities are produced, how people make sense of places and build senses of place, and how people produce and communicate knowledge and meaning.
Minerals are formed by changes in chemical energy in systems which contain one fluid or vapor phase. In nature, minerals are formed by crystallisation or precipitation from concentrated solutions. These solutions are called as ore-bearing fluids. Ore-bearing fluids are characterised by high concentration of certain metallic or other elements.
Fluids are the most effective agents for the transport of material in the mantle and the Earth's crust.
Soils are complex mixers forming the skin of the earth's surface. Soil is a dynamic layer in which many complex chemical, physical and biological activities are going on constantly. Soils become adjusted to conditions of climate, landform and vegetation, and will change internally when those controlling conditions change. Soils are products of weathering. Soils play a dominant role in earth's geomorphic processes in a cyclic manner. The characteristics of soils are very essential for several reasons. This module highlights these characteristics.
GIS TECHNIQUES IN WATER RESOURCES PLANNING AND MANAGEMENT IN CHAMARAJANAGAR ...Prof. A.Balasubramanian
The over-exploitation and contamination of groundwater continue to threaten the long-term sustainability of our precious water resources, in spite of the best efforts made by various agencies.
This has many serious implications to the economic development of a country like India. Lack of
judicious planning and integration of environmental consideration to ground water development
projects are primarily responsible for such a state of affair in the ground water sector. Geographical Information Systems could be of immense help in planning sustainable ground water management strategies, especially in hard rock areas with limited ground water potential. Data collected from
Satellite Imagery and through field investigations have been integrated, on a GIS platform, for demarcation and prioritization of areas suitable for ground water development and ground water augmentation. An attempt has also been made to assess the vulnerability of the area to ground water
contamination. This paper demonstrates the utility of GIS in planning judicious management of ground water resources in a typical hard rock area of Chamarajanagar Taluk, Karnataka, state India.
Nanobiomaterials are very effective components for several biomedical and pharmaceutical studies. Among the metallic, organic, ceramic and polymeric nanomaterials, metallic nanomaterials have shown certain prominent biomedical applications. Enormous works have been done to synthesize, analyse and administer the metallic nanoparticles for various kinds of medical and therapeutic applications, during the last forty years. In these analyses, the prominent biomedical applications of ten metallic nanobiomaterials have been reviewed from various sources and works. It has been found that almost nine of them are used in a very wide spectrum of medical and theranostic applications.
A variety of Nano-biomaterials are synthesised, characterised and tested to find out their potentialities by global scientific communities, during the last three decades. Among those, nanostructured ceramics, cements and coatings are being considered for major use in orthopaedic, dental and other medical applications. The development of novel biocompatible ceramic materials with improved biomedical functions is at the forefront of health-related applications, all over the world. Understanding of the potential biomedical applications of ceramic nanomaterials will provide a major insight into the future developments. This study reviews and enlists the prominent potential biomedical applications of ceramic nanomaterials, like Calcium Phosphate (CaP), Tri-Calcium Phosphate (TCP), Hydroxy-Apatite(HAP), TCP+HAP, Si substituted HAP, Calcium Sulphate and Carbonate, Bioactive Glasses, Bioactive Glass Ceramics, Titania-Based Ceramics, Zirconia Ceramics, Alumina Ceramcis and Ceramic Polymer Composites.
The present forest and tree cover of the country is 78.37 million ha in 2007 which is 23.84% of the geographical areas and it includes 2.82% tree cover. This becomes 25.25%, if the areas above tree line i.e., 4000m are excluded from the total geographical area. The forest cover is classified into 3 canopy density classes.
1. Very Dense Forest (VDF) with canopy density more than 70%
2. Moderately Dense Forest (MDF) with Canopy density between 40-70% and
3. Open Forest (OF) with Canopy density between 10-40%
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
2. 2
Objectives :
After attending this module, the user would be
able to know about the most popular methods of
groundwater exploration.
The surface geomorphological, geological,
structural, hydrogeological, geophysical and
remote sensing methods will be known. In
addition, the user will also get some basic ideas
about the subsurface methods of groundwater
exploration like well-logging and test drilling.
3. 3
Introduction
Groundwater is an invisible natural resource. It is
available in different proportions, in various rock
types and at various depths, on the surface layer
of the earth. In the historical past, when there is
no visible flow of water along the rivers, people
used to dig small pits, in the river alluvium, wait
and collect the groundwater coming through
seepage and use it for their drinking purposes and
for meeting the domestic needs.
4. 4
Similarly, to the people of mountainous regions,
natural springs provided the sources of water
supply.
Springs are the outcome of seepage from any
groundwater system, in hilly terrains or in
limestone regions.
More than 60 percent of the global population
thrives by using only the groundwater resources.
The groundwater which was existing at shallow
depths in the open wells, has gone deep due to
over-exploitation.
5. 5
Exploring these water sources become a
challenging task to geo-scientists.
Renewable resource
Groundwater is a renewable source. Groundwater
gets replenished after every rainfall. This is called
as rainfall recharge. The level of water seen in an
open well denotes the uppermost surface of the
zone of saturation of the porous media. This is
called as the water table.
6. 6
After every recharge, the water table raises,
denoting that the porous media has saturated with
more water. When we pump out water, the water
level goes down.
Continuous pumping of water, beyond the
recharge, will make the wells go dry and force to
deepen the well.
The search of groundwater got increased, due to
the non-availability of sources and due to the
declining water tables.
7. 7
Heterogeneous distribution
Groundwater is not uniformly distributed
everywhere. The occurrence of groundwater
varies from formation to formation. In a typical
crystalline hard rock terrain, the quantitative
occurrence of groundwater depends on the
weathered and fractured zones. The occurrence of
groundwater in a sedimentary terrain will be more
promising.
8. 8
Groundwater prospecting is a very thought
provoking scientific exercise in most of the
places.
There is a need to understand the methods of
groundwater exploration, as it is a practical
decision-making approach.
This module highlights some of the general
methods of groundwater exploration.
Exploring groundwater
9. 9
Groundwater exploration is a typical task of a
hydrogeologist or an engineer.
Identifying the location of its availability is a
challenging task. Exploration of groundwater
requires a basic understanding of its position in
the subsurface geological setup.
Groundwater Exploration is attempted through
either by direct or indirect methods. Test drilling
is the direct approach to find out the resource.
This is an expensive affair.
10. 10
Every individual can not go for test drilling.
During the last two centuries, more and more
techniques have been developed to explore the
groundwater.
They are classified into surface and sub-surface
methods.
Surface methods
The surface methods are easy to operate and
implement.
11. 11
These require minimum facilities like topo-sheets,
maps, reports, some field measurements and
interpretations of data in the laboratories.
The surface methods of groundwater exploration
include the following:
–Esoteric Methods
–Geomorphologic methods
–Geological & structural Methods
–Soil and Micro-Biological Methods
–Remote Sensing Techniques
–Surface Geophysical Methods
12. 12
Subsurface methods
The subsurface methods of groundwater
exploration includes both Test Drilling &
Borehole Geophysical Logging techniques. When
compared to the surface methods, the subsurface
methods are very expensive.
These are done for government level projects
where large scale investigations are carried out to
ascertain the results of surface surveys.
13. 13
The subsurface methods are very accurate
methods as the help in direct observations of
features in the form of bore-hole lithologs as core
samples and also geophysical measurements of
formation properties.
Esoteric methods
The Esoteric methods are the ancient methods.
These are the oldest water divining methods
practiced by ancient people for several centuries.
They are also called as water-dowsing.
14. 14
People believed that the flow of groundwater can
induce some vital currents above the surface.
When a wet plant twig is moved above such
zones, it tends to rotate the twig as well. Wet
twigs of trees, husk-removed coconuts, watches
and other materials have been used as dowsing
materials.
The person handling the twig has some role of
induction and hence it is not applicable to
everybody attempting to divine water. All these
methods have been practiced since 17th
century.
15. 15
There is no scientific explanation available with
reference to these approaches. Probability of
success is a mere coin-tossing experiment. These
methods are called as water divining.
Water Witching
Water witching is a traditional method adopted by
people to detect bore-well locations. Using a
forked stick to locate water source is known as
water witching.
16. 16
Although this method is lacking any scientific
justification for the method, water witches
diligently practice the art wherever people can be
persuaded of its potential value.
Commonly, the method consists of holding a
forked stick in both hands and walking over the
local area until the butt end is attracted
downward-ostensibly by subsurface water.
It is amazing that the idea of supernatural powers
has such a continued fascination for people to use
despite its limitations.
17. 17
Geomorphological Methods
Surface drainage is the subdued replica of
topography. It is controlled by the basement
rocks. Mostly, groundwater flow coincides with
the surface drainages. The streams and water
courses may also be controlled by some
underlying structures. Junctions of streams at the
down slopes are promising zones for groundwater.
Landforms originate due to several geological
processes.
18. 18
Some of them are likely to contain relatively
permeable strata.
River-borne modern alluvial terraces, floodplains,
stratified valley-fill deposits in abandoned
channels, glacial outwash and moraine deposits
are good landforms for groundwater.
Alluvial fans, beach ridges, partly drift-filled
valleys, sand dunes, moist depressions, and
marshy environments are good localities.
19. 19
Study of Land forms
Landforms are the likely indicators to show the
relatively permeable strata.
The locations of modern alluvial terraces and
floodplains, stratified valley-fill deposits, glacial
outwash plains, glacial deltas, kames , moraine
complexes, eskers, alluvial fans and beach ridges
are good locations for groundwater occurrence.
20. 20
Partly drift-filled valleys marked by a chain of
elongate closed depressions,
largely masked bedrock valleys cutting across
modern valleys that are indicated by local non-
slumping of weak shale strata in valley sides,
sand dunes assumed to overlie sandy glacio-
fluvial sediments,
nearby locations of lakes and streams are very
good indicators for groundwater prospecting.
21. 21
Topography and Drainage
Physiographic methods analyse the surface
topography and drainages.
The locations of confluence and junctions of
surface streams at the downstream points of small
watersheds are good locations for groundwater for
confluence.
Hydraulic gradients of groundwater systems will
always follow the topographic gradients and
slopes.
22. 22
Such locations are also suitable for water
collection and storage for recharge.
Drainage density of stream network
Drainage density is the ratio between the total
length of all streams and the area of watershed or
river basin. The resultant drainage density is used
to indicate the potentiality of groundwater. If the
drainage density is low, groundwater potentiality
will be more.
23. 23
If it is high, due to more streams, runoff will be
more.
Geological Methods
A geologic investigation begins with the
collection, analysis, and hydrogeologic
interpretation of existing topographic maps, aerial
photographs, geologic maps and logs, and other
pertinent records.
24. 24
This should be supplemented, when possible, by
geologic field reconnaissance and by evaluation
of available hydrologic data on stream flow and
springs, well yields, groundwater recharge,
discharge, and levels and water quality.
In some places, the drainages may be fully
controlled by the presence of minor and major
structures like joints, faults and lineaments.
Such zones are good and potential zones for
groundwater exploration.
These are the conduits for groundwater flow.
25. 25
Structural methods
Contact points between permeable water-bearing
strata overlying relatively impermeable strata-
usually along the sides of valleys that cut across
the interface between different strata are suitable
locations for groundwater.
Springs occurring on or near the base of hillsides,
valley slopes, and local scarps are indicators of
groundwater occurrence over hilly terrain.
26. 26
Dykes are good barriers for arresting the flow of
groundwater.
Location of dykes and analyzing their dip and
strike help in selecting the groundwater potential
zones in the upstream side.
Well-inventory
Well-inventory is a method of analyzing the well-
cuttings and inner surfaces of open dug wells to
know about the subsurface geology, structures,
seepage zones, fluctuations of water levels, rate of
recovery after pumping and the geo-
environmental setting of the wells in a region.
27. 27
This method helps to analyse the data collected
from more number of the wells of a region and
come to a conclusion about the regional
groundwater potentialities.
The groundwater flow paths could be easily
identified through well-inventory.
Promising zones could be identified for further
investigations though this method.
28. 28
Soil and Micro-Biological Methods
Geo-botanical indicators are valuable tools in
groundwater exploration.
The anomalous growth of vegetation and
alignment of big trees on a straight line, growth of
termite mounds and location of age old, deep
rooted heritage trees can indicate the occurrence
of groundwater at shallow depths.
Presence of Halophytes, plants with a high
tolerance for soluble salts, and white efflorescence
of salt at ground surface, indicate the presence of
shallow brackish or saline groundwater.
29. 29
Xerophytes, the well-known desert plants ,
subsisting on minimal water, suggest a
considerable depth to the water table.
All these are supplementary tools in detecting the
locations of groundwater zones.
Moist depressions and seepages
Moist depressions,
marshy environments, and seepages,
string of alkali flats or lakes (playas) along
inactive drainage systems, salt precipitates (e.g.,
salt crusts),
30. 30
localized anomalous-looking "burn out" patches
in the soil, and
vegetation associated with salt migration and
accumulation are good indicators for groundwater
availability.
Depression springs, where land surface locally
cuts the water table or the upper surface of the
zone of saturation, Contact springs containing a
permeable water-bearing strata overlying
relatively impermeable strata-usually along the
sides of valleys that cut across the interface
between different strata are good locations.
31. 31
The presence of artesian springs occurring on
undulating upland till plains, and artesian springs
occurring on or near the base of hillsides, valley
slopes, and local scarps are very good indicators.
Geophysical methods
Exploring the ground water by geophysical
method is termed Ground water geophysics.
32. 32
Geophysical investigations are conducted on the
surface of the earth to explore the ground water
resources by observing some physical parameters
like density, velocity, conductivity, resistivity,
magnetic, electromagnetic & radioactive
phenomena.
Geophysical methods comprise of measurement
of signals from natural or induced phenomena of
physical properties of sub surface formation.
Geophysical methods detect the differences, or
anomalies of physical properties within the earth's
crust.
33. 33
Density, magnetism, elasticity, and electrical
resistivity are properties that are most commonly
measured.
The purpose of exploration is to detect the
indirect indicators and locate the potential zones
for exploitation. The main geophysical methods
which are useful in solving some of the problems
of hydrogeology, are the Electrical, Seismic,
Gravity, and Magnetic methods.
34. 34
Gravity Method
The gravity method is a widely used geophysical
method for finding out mineral resources and
groundwater in sedimentary terrain.
Gravimeters are used in this method to measure
the differences in density on the earth's surface
that may indicate the underlying geologic
structures.
35. 35
Because the method is expensive and because
differences in water content in subsurface strata
seldom involve measurable differences in specific
gravity at the surface, the gravity method has little
application to groundwater prospecting.
Under special geologic conditions, such as a large
buried valley, the gross configuration of an
aquifer can be detected from gravity variations.
36. 36
Magnetic Method
The magnetic method enables detecting the
magnetic fields of the earth which can be
measured and mapped. Magnetometers are the
equipments used to measure the magnetic fields
and variations.
Because magnetic contrasts are seldom associated
with groundwater occurrence, the method has
little relevance for exploring groundwater.
37. 37
Seismic Method
Seismic methods are of two kinds as seismic
refraction and reflection methods.
The seismic refraction method involves the
creation of a small shock at the earth's surface
either by the impact of a heavy instrument or by a
small explosive charge and measuring the time
required for the resulting sound, or shock, wave to
travel known distances.
38. 38
Seismic waves follow the same laws of
propagation as light rays and may be reflected or
refracted at any interface where a velocity change
occurs. Seismic reflection methods provide
information on geologic structure thousands of
meters below the surface, whereas seismic
refraction methods-of interest in groundwater
studies-go only about 100 meters deep. The
travel time of a seismic wave depends on the
media through which it is passing through. The
velocities are greatest in solid igneous rocks and
least in unconsolidated materials.
39. 39
Based on these indications, it is possible to
delineate the subsurface zones of fractures,
fissures, faults and lineaments.
Analyzing Seismic velocities
A basic understanding of the characteristic
seismic velocities for a variety of geologic
materials is necessary. These velocities help to
identify the nature of alluvium or bedrock. In
coarse alluvial terrain, seismic velocity increases
markedly from unsaturated to saturated zones.
40. 40
In seismic method, the depth to water table can
be mapped, with an accuracy of 10 percent,
where the geologic conditions are relatively
uniform. The changes in seismic velocities are
governed by changes in the elastic properties of
the formations. The greater the contrast of these
properties, the more clearly the formations and
their boundaries can be identified.
41. 41
Electrical resistivity method
The purpose of electrical surveys is to determine
the subsurface resistivity distribution by making
measurements on the ground surface. From these
measurements, the true resistivity of the
subsurface can be estimated. The ground
resistivity is related to various geological
parameters such as the mineral and fluid content,
porosity and degree of water saturation in the
rock.
42. 42
Electrical resistivity surveys have been used for
many decades in hydrogeological, mining and
geotechnical investigations. More recently, it has
been used for environmental surveys. Each
electrical property is the basis for a geophysical
method.
The resistivity measurements are normally made
by injecting current into the ground through two
current electrodes (C1 and C2 in Figure 1), and
measuring the resulting voltage difference at two
potential electrodes (P1 and P2).
43. 43
From the current (I) and voltage (V) values, an
apparent resistivity (pa) value is calculated, using
pa = k V / I, where k is the geometric factor
which depends on the arrangement of the four
electrodes. The electrode arrangement in these
investigations are called as arrays. Some of the
most common electrode arrays are Wenner,
Schlumberger, pole-pole, pole-dipole and dipole-
dipole array.
44. 44
Vertical electrical sounding
Vertical electrical sounding, VES, is used to
determine the resistivity variation with depth.
Single VES should only be applied in areas,
where the ground is assumed to be horizontal
layered with very little lateral variation, since the
sounding curves only can be interpreted using a
horizontally layered earth (1D) model. To
measure the apparent resistivity values a
resistivity meter is used.
45. 45
Resistivity meters normally give a resistance
value, R = V/I, so in practice the apparent
resistivity value is calculated by pa = k R.
The calculated resistivity value is not the true
resistivity of the subsurface, but an “apparent”
value which is the resistivity of a homogeneous
ground which will give the same resistance value
for the same electrode arrangement. The
relationship between the “apparent” resistivity and
the “true” resistivity is a complex relationship.
46. 46
To determine the true subsurface resistivity, an
inversion of the measured apparent resistivity
values using a computer program must be carried
out. The measured apparent resistivity values are
normally plotted on a log-log graph paper. To
interpret the data from such a survey, it is
normally assumed that the subsurface consists of
horizontal layers.
47. 47
Profiling
Another classical survey technique is the profiling
method. In this case, the spacing between the
electrodes remains fixed, but the entire array is
moved along a straight line. This gives some
information about lateral changes in the
subsurface resistivity, but it cannot detect vertical
changes in the resistivity. Interpretation of data
from profiling surveys is mainly qualitative.
48. 48
The most severe limitation of the resistivity
sounding method is that horizontal (or lateral)
changes in the subsurface resistivity are
commonly found. In many engineering and
environmental studies, the subsurface geology is
very complex where the resistivity can change
rapidly over short distances. The resistivity
sounding method might not be sufficiently
accurate for such situations.
Resistivity surveys give a picture of the
subsurface resistivity distribution.
49. 49
To convert the resistivity picture into a geological
picture, some knowledge of typical resistivity
values for different types of subsurface materials
and the geology of the area surveyed, is
important.
The resistivity values of common rocks and soil
materials are given below: table
Sl.No. RESISTIVITY
-m
AQUIFER CHARACTERISTICS
1. < 20 Indicates a chloride ion concentration of 250
ppm (Aquifer may be fine sand & Limestone)
2. 50 – 70 Porosity is the principal determinant of
resistivity
50. 50
3. 20 – 30 Pore fluid conductivity dominates / affected by
both water quality and lithology
4. 30 – 70 Affected by both water quality and lithology
5. < 10 Delineate sediments enriched with salt water
6. < 1 Clay / sand saturated with salt water
7. 15 – 600 Sand and Gravel saturated with fresh water
8. 5 Saltwater or Clay with saltwater
9. < 10 Brackish aquifer
10. 10 – 20 Moderately fresh
11. 20 – 160 Freshwater
12. 0.2 – 0.8 Clay
13. 0.6 – 5 Dry sand contaminated
14. 0.3 – 0.8 Brine bearing sand
15. 3 – 6 Red clay
16. < 19 Clay / clay mixed with kankar
17. 64 – 81 Weathered sandstone
18. 57 – 111 Weathered granite and other crystalline rocks
19. < 10 Saline coastal zone sand (Sedimentary)
51. 51
20. 10 – 20 Clay with or without diffused water
21. 20 – 60 Freshwater zone
22. 200-10000 Crystalline rocks: Granite and other igneous
rocks and crystalline schist of normal physical
character, compact sand stones, quartzite,
marbles
23 100-1000 Consolidated sedimentary rocks:Slates, shale,
sand stone, limestone
24 0.5-100 Unconsolidated sedimentary rocks: Marls,
clays, sands, alluvium and surface soils
25 4-800 Oil bearing sands:
Igneous and metamorphic rocks typically have
high resistivity values.
52. 52
The resistivity of these rocks is greatly dependent
on the degree of fracturing, and the percentage of
the fractures filled with ground water.
Sedimentary rocks, which usually are more
porous and have a higher water content, normally
have lower resistivity values. Wet soils and fresh
ground water have even lower resistivity values.
Clayey soil normally has a lower resistivity value
than sandy soil. However, note the overlap in the
resistivity values of the different classes of rocks
and soils.
53. 53
This is because the resistivity of a particular rock
or soil sample depends on a number of factors
such as the porosity, the degree of water
saturation and the concentration of dissolved salts.
The resistivity of ground water varies from 10 to
100 ohm•m. depending on the concentration of
dissolved salts. Note the low resistivity (about 0.2
ohm•m) of sea water due to the relatively high salt
content. This makes the resistivity method an
ideal technique for mapping the saline and fresh
water interface in coastal areas.
54. 54
Wenner array
This is a robust array which was popularized by
the pioneering work. The Wenner array is
relatively sensitive to vertical changes in the
subsurface resistivity below the centre of the
array. However, it is less sensitive to horizontal
changes in the subsurface resistivity. The Wenner
array has a moderate depth of investigation.
55. 55
For the Wenner array, the geometric factor is
2(22/7)a, which is smaller than the geometric
factor for other arrays. Among the common
arrays, the Wenner array has the strongest signal
strength.
This can be an important factor if the survey is
carried in areas with high background noise.
56. 56
Schlumberger array
In the Schlumberger array, A and B are current
electrodes, and M and N are potential electrodes.
Let the current I enter the ground at A and return
at B. Assuming the medium below the surface of
the earth to be homogeneous and isotropic of
resistivity p, the potentials V M and V N as
measured at M and N, respectively.
57. 57
The calculations are done using these two
equations:
VM = pl/27r 1/(a - b/2) - 1/(a + b/2)
VN =pl/27r 1/(a + b/2) - 1/(a - b/2)
from which p = 7r(a 2/b-b/4) (V M -VN /I).
Denoting (VM -VN ) by AV, and acknowledging
the fact that, in reality, the medium is anisotropic,
the apparent resistivity pa as measured by the
Schlumberger array is given by:
Pa = 7r(a 2 /b - b/4) AV/I
58. 58
If a and b are measured in meters, and oV and I in
millivolts and milliamperes respectively, pa
would be in ohm-meters (Slur).
Equation (1) may be written as:
Pa =K/I AV
where K = (a2 /b - b/4) is the geometric factor for
the Schlumberger array.
59. 59
Dipole-dipole array
This array has been, and is still, widely used in
resistivity/I.P. surveys because of the low E.M.
coupling between the current and potential
circuits. The spacing between the current
electrodes pair, C2-C1, is given as “a” which is
the same as the distance between the potential
electrodes pair P1-P2. Thus the dipole-dipole
array is very sensitive to horizontal changes in
resistivity, but relatively insensitive to vertical
changes in the resistivity.
60. 60
That means that it is good in mapping vertical
structures, such as dykes and cavities, but
relatively poor in mapping horizontal structures
such as sills or sedimentary layers.
Interpretation of data
The interpretation of each VES curve is carried
out in two steps.
First, an approximate interpretation is obtained by
the curve-matching methods, and another
interpretation is based on the results obtained
through the automatic interpretation using a
computer program.
61. 61
Finally, the layer-wise resistivities and
thicknesses are obtained from these
interpretations. Using them spatial variation maps
depicting the low resistivity contours and good
thickness aquifer horizons can be delineated.
Electromagnetic Method
The term electromagnetism is defined as the
production of a magnetic field by current flowing
in a conductor.
62. 62
Coiling a current-carrying conductor around a
core material that can be easily magnetized, such
as iron, can form an electromagnet. The magnetic
field will be concentrated in the core. This
arrangement is called a solenoid. The more turns
we wrap on this core, the stronger the
electromagnet and the stronger the magnetic lines
of force become. The magnetic field that
surrounds a current-carrying conductor is made up
of concentric lines of force. The strength of these
circular lines of force gets progressively smaller
the further away from the conductor.
63. 63
If a stronger current is made to flow through the
conductor, the magnetic lines of force become
stronger.
The strength of the magnetic field is directly
proportional to the current that flows through the
conductor. There are two methods as Passive and
Active methods. The Passive method uses the
natural ground signals (e.g., magnetotellurics),
natural sources like lightning, magnetosphere
activities, etc.
64. 64
The Active method uses a transmitter to induce
ground current, using an artificial source.
Principles of EM Surveying
The first step is to generate EM field by passing
an AC through a wire coil ( transmitter). The EM
field propagates above and below ground. If there
is conductive material in ground, magnetic
component of the EM wave induces eddy currents
(AC) in conductor.
65. 65
The eddy currents produce a secondary EM field
which is detected by the receiver. The receiver
also detects the primary field (the resultant field is
a combination of primary and secondary which
differs from the primary field in phase and
amplitude). After compensating for the primary
field (which can be computed from the relative
positions and orientations of the coils), both the
magnitude and relative phase of the secondary
field can be measured.
66. 66
The difference in the resultant field from the
primary provides information about the geometry,
size and electrical properties of the subsurface
conductor.
The apparent conductivity measured is the
average conductivity of one or more layers in the
ground in the proximity of the instrument, to a
depth of investigation. The depth of investigation
is dependent on the coil spacing, orientation,
operating frequency of the instrument, and the
individual conductivity of each ground layer.
67. 67
General Principles of EM Operation
There are two methods of EM surveys. One is the
TDEM which means Time-domain (TDEM) EM
surveys. The measurements are done as a
function of time. the Time-Domain
Electromagnetic (TDEM) methods are based on
the principle of using electromagnetic induction to
generate measurable responses from sub-surface
features. When a steady current in a cable loop is
terminated a time varying magnetic field is
generated.
68. 68
As a result of this magnetic field, eddy currents
are induced in underground conductive materials.
The decay of the eddy currents in these materials
is directly related to their conductive properties,
and may be measured by a suitable receiver coil
on the surface.
The second method is the FDEM –Frequency-
domain (FDEM) EM surveys.
69. 69
It is related to the measurements at one or more
frequencies. The FDEM Transmitter produces
continuous EM field. The secondary field is
determined by nulling the primary field ( need
two coils). The TDEM-Primary field is
applied in pulses ( 20-40 ms) then switched off
and the secondary field measured ( same coil
can be transmitter and receiver, more often
large coil on ground and move small coil
around).
70. 70
Geophysical Logging Techniques
The term “logging” refers to making records of
some measurements or observations.
Borehole geophysical logging is a procedure to
collect and transmit specific information about the
geologic formations penetrated by a well by
raising and lowering a set of probes or sondes that
contain water-tight instruments in the well.
71. 71
The data obtained is normally used to determine
the general lithology of formations, distribution
of structures, vertical flow of fluids, and the
water-yielding capabilities of the formations. The
geophysical logging of boreholes came a long
way since 1927, when
Schlumberger brothers ran the first electric log.
In India the geophysical logging of water well
was carried out for the first time in 1953 by GSI.
72. 72
Basically, there are two types of logging
techniques- first utilizing the natural source &
second utilizing stimulated controlled source.
Geophysical logging technique utilizes the
measurement of certain physical parameters
across different subsurface formations with the
help of sensing probe inside the bore hole
providing a continuous record of these parameters
versus depth.
73. 73
These parameters are interpreted in terms of
lithology, porosity, moisture content & quality of
formation fluids. Different physical properties
like electrical conductivity, magnetic
susceptibility, radioactivity & velocity etc are
utilized.
The primary purpose of well logging is the
identification of formations traversed by a bore
hole & salinity of fluids. Well logging is used
a) for stratigraphic correlation, detection of bed
boundaries, porous & permeable zones
74. 74
b) for the water well design & construction and
c) for sea water intrusion studies of coastal
aquifers.
Logging methods
The different types of well-logging methods are:
a) Electric logging – electrical resistivity &
Self-Potential(SP).
b) Radioactive logging – gamma ray & neutron
logs.
c) Induction logging.
75. 75
d) Sonic logging.
e) Fluid logging – temperature, fluid
resistivity, flow meter & tracer logging.
f) Caliper logging.
Electric well logging involves the continuous
recording of electrical resistance / resistivity & SP
of the formations by a drill bore hole. In the SP
log, the potential drop between bore hole
electrode & a reference electrode @ the surface is
recorded.
76. 76
The SP logs are highly useful in deciphering
saline water & clay predominant zones. The
Resistivity logs are used for ground water &
mineral explorations.
Photogeology
Photogeology is the art of making aerial
photographs that are suitable for analyzing the
earth’s physiographic features, rack types,
structures, mineralized zones, water resources,
types of vegetation, zones of cultivation and
urbanization.
77. 77
The Photographs of the earth taken from the
aircraft or satellite can provide useful information
regarding groundwater conditions. The
technology of remote sensing has developed
rapidly in recent years. Stereoscopic examination
of black-and-white aerial photographs has gained
steadily in importance.
Observable patterns, colors, and relief make it
possible to distinguish differences in geology,
soils, soil moisture vegetation, and land use.
78. 78
Thus, photogeology can differentiate between
rock and soil types and indicate their permeability
and areal distribution-and hence areas of
groundwater recharge and discharge. Maps
classifying an area into good, fair, and poor
groundwater yields can be prepared. Aerial
photographs also reveal the fracture patterns in
rocks, which can be further related to the porosity,
permeability, and ultimately the well yields.
79. 79
They are suitable for identifying the formations
that are potential zones for the occurrence of
groundwater.
Remote Sensing techniques
Remote sensing is the science (and to some
extent, art) of acquiring information about the
Earth's surface without actually being in contact
with it. This is done by sensing and recording
reflected or emitted energy and processing,
analyzing, and applying that information.
80. 80
In much of remote sensing, the process involves
an interaction between incident radiation and the
targets of interest. Remote sensing shows an
increasing role in the field of hydrology and
water resources development. Remote sensing
provides multi-spectral, multi-temporal and multi-
sensor data of the earth’s surface which are
suitable for mineral explorations, water resources
evaluation, environmental monitoring and
groundwater targeting.
81. 81
Remote sensing techniques help in the
demarcation of groundwater potential zones,
identification of groundwater recharge sites and,
to analysis the future artificial recharge sites.
Applications of remote sensing
Satellite data products are much varied depending
upon the spectra considered.
82. 82
The high resolution satellite images are
interpreted (visually or digitally) to identify the
groundwater potential zones. Thematic layers are
prepared based on hydrogeomorphic units, land-
use/ land-cover/ lineaments, rock types, structures
and many other features.
The methodology involves the delineation of
hydrogeomorphic units which are influenced by
the hydro geological conditions of the area.
83. 83
The hydrogeological conditions are controlled by
the lithology, geomorphology, structures like
lineaments, faults and fractures.
The visual interpretation of satellite data in
conjunction with limited field verification of these
features will focus on the priority zones.
Most of them are reflected as hydrogeomorphic
units.
Remote sensing provides the distribution of these
units.
84. 84
Conclusion
Several geological, hydrogeological and
geophysical methods are employed to target the
groundwater potential zones. The interpretation
of satellite images and aerial photographs also
help more in this process.
Groundwater exploration is a very unique
exercise.
As it is a hidden resource, various indirect
methods are attempted to identify the points.
85. 85
The success in the groundwater targeting lies in
experience of understanding the geological
conditions, structural conditions and
hydrogeological conditions which favour the
occurrence of groundwater.
The modern tools like remote sensing and aerial
photography also provide a lot of spatial data for a
quick understanding of the domain for a better
decision-making.