<?xml version="1.0" encoding="UTF-8"?>
<TEI xmlns="http://www.tei-c.org/ns/1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xml:space="preserve" xsi:schemaLocation="http://www.tei-c.org/ns/1.0 https://raw.githubusercontent.com/kermitt2/grobid/master/grobid-home/schemas/xsd/Grobid.xsd">
	<teiHeader xml:lang="en">
		<fileDesc>
			<titleStmt>
				<title level="a" type="main">Detection of Fracture Zones for Groundwater Investigation from Interpretation of VLF-EM Anomalies of Kwara State Polytechnic Ilorin and its Environs</title>
			</titleStmt>
			<publicationStmt>
				<publisher>Global Journals Organisation</publisher>
				<availability status="free"><licence/><p>This is an open access work licensed under a Creative Commons Attribution 4.0 International license. Please email us for details and permissions.</p></availability>
			<pubPlace>Cambridge, United States</pubPlace><date when="2019-01-15">15 January 2019</date></publicationStmt>
			<sourceDesc>
				<biblStruct type="article">
					
					
					<idno type="MD5">A2482D9AD38975EED98F74F317CB2D24</idno>
				<analytic><author><persName><forename type="first">Sunday,</forename><surname>J.A.</surname></persName></author><author><persName><forename type="first">Usman,</forename><surname>A.</surname></persName></author><author><persName><forename type="first">Ologe,</forename><surname>O.</surname></persName></author><author><persName><forename type="first">Lawal,</forename><surname>T.O.</surname></persName></author></analytic><monogr><title level="j" type="main">Global Journal of Human Social Sciences</title><title level="j" type="nlm-ta">GJHSS</title><idno type="eISSN">2249-460X</idno><idno type="ISSN">0975-587X</idno><idno type="DOI">10.34257/GJHSS</idno><imprint><pubPlace>Cambridge, United States</pubPlace><publisher>Global Journals Organisation</publisher><biblScope unit="vol">19</biblScope><biblScope unit="issue">1</biblScope><biblScope type="fpage">17</biblScope><biblScope type="lpage">41</biblScope></imprint></monogr></biblStruct>
			</sourceDesc>
		</fileDesc>
		<encodingDesc>
			<appInfo>
				<application version="11.4.2" ident="JournalKaleidoscope" when="2022-04-03T22:19+0000">
					<desc>By Softinator Dynamics Pvt. Ltd.</desc>
					<ref target="https://softinator.com"/>
				</application>
			</appInfo>
		</encodingDesc>
		<profileDesc>
			<textClass>
				
			<keywords><term>very low frequency â??"electromagnetic (VLF-EM)</term><term>moro lga</term><term>abem wadi</term><term>em anomalies</term><term>fracture zones</term><term>groundwater.</term></keywords></textClass>
			<abstract>
<div xmlns="http://www.tei-c.org/ns/1.0"><p>The Very Low Frequencyâ??"Electromagnetic (VLF-EM) geophysical methods have been used to map selected settlements in Kwara State Polytechnic (Permanent Site) and its environs, Ilorin, Northcentral Nigeria with a view to determine the groundwater potential of the area. A total of thirteen (13) profiles were covered during VLF data collection with 20m sample interval along each profile with spread length of between 100m. The VLF data were collected using ABEM WADI instrument. The data were interpreted using KHFFILT software. The qualitative interpretation of the acquired VLFâ??"EM data identified areas of hydro-geologic importance. The results further showed that the EM anomalies vary greatly. Some of the anomaly peaks are narrow and sharp while others are broad with varying width extent. The values of the filtered real range from -0.9 to 22.5 across the study area. The study area is adjudged, based on the VLF data interpretation which indicates the presence of interconnected fracture zones, to have potentially good prospects for groundwater development; while recommendation is made for further geophysical methods to be employed in order to detect suitable locations for productive and sustainable borehole.</p></div>
			</abstract>
		</profileDesc>
	<revisionDesc><change when="2018-12-10">Received: 10 December 2018</change><change when="2019-01-03">Accepted: 3 January 2019</change><change when="2019-01-15">Published: 15 January 2019</change></revisionDesc></teiHeader>
	<text xml:lang="en">
		<body>
<div xmlns="http://www.tei-c.org/ns/1.0"><head>Introduction he VLF-EM technique was developed in the 1960s</head><p>with the use of the transmitted signals of the already established powerful radio communication stations (in the 10-30 kHz band). The transmitters of these stations generate primary fields with horizontal magnetic components ( y H ), and vertical electric component ( z E ). Both components are perpendicular to the direction of propagation (X). At great distance, their wave front is considered uniform and plane. It is known that the induction caused by the primary magnetic field in a homogenous earth modifies the y H component and creates a horizontal electric component x E , and when a subsurface conductor is encountered, a secondary magnetic field will be generated <ref type="bibr">(Mahemedet al., 1998)</ref>.In recent times, the VLF EM method has been applied successfully to map the resistivity contrast at boundaries of fractured zones having a high degree of connectivity <ref type="bibr">(George et al., 2013)</ref>. Also VLF method yields a higher depth of penetration in hard rock areas because of their high resistivity <ref type="bibr" target="#b12">(McNeill and Labson, 1991)</ref>. VLF method is capable of delineating fractures in lateral direction effectively compared to resistivity sounding <ref type="bibr" target="#b22">(Sharma and Baranwal, 2005)</ref>, characterize aquifer structures in a complex environment <ref type="bibr">(Ozeginet al., 2012)</ref>, underground water contamination by solid waste <ref type="bibr" target="#b4">(Deborah and Ayobami, 2013)</ref> and examination of the fault pattern of industrial estate <ref type="bibr" target="#b26">(Theophilus and Lukman, 2012)</ref>.</p><p>The Very Low Frequency Electromagnetic (VLF -EM) method has found useful application in groundwater investigation in basement terrain, most especially as a reconnaissance tool <ref type="bibr" target="#b3">(Amadi and Nurudeen, 1990;</ref><ref type="bibr" target="#b18">Olorunfemi et. al., 1995)</ref>. It is an accepted fact that most of the ground VLF-EM anomalies are caused by the galvanic effect <ref type="bibr" target="#b11">(McNeil, 1985)</ref> where the influence of frequency may be neglected <ref type="bibr">(Guerin et al., 1994)</ref>. This method of geophysical prospecting was primarily developed for the delineation of sheet -like metallic conductors, which are often concentrated within fault and fracture zones which are known to be good groundwater aquifers, particularly when the fracture frequency is high <ref type="bibr" target="#b18">(Olorunfemi et. al., 1995)</ref>. The technique may be applied indirectly to the location of sites with appreciably thick overburden to the mapping of geological structures such as fault and fracture zones that are favourable to groundwater accumulation <ref type="bibr">(McNeil, 1980;</ref><ref type="bibr" target="#b21">Palacky et. al., 1981;</ref><ref type="bibr">Adiat et. al., 2009)</ref>.</p><p>The mapping of fracture zone which is a break in crystalline basement rock due to tectonic forces or intrusion of magmatic bodies is important for civil engineering and hydrogeological applications. In civil engineering, it helps to locate the safest depth to lay the foundation of buildings. This study was driven by the desire to investigate water bearing fracture zones in the area under investigation using very low frequency (VLF) electromagnetic method. Most boreholes drilled in the past in the area are unproductive and due to this failure, it is therefore necessary to use an appropriate geophysical method to locate the fracture zones. This became important as the inhabitants of the study area depend solely on streams, lakes and groundwater for their domestic needs and otherwise.</p></div>
<div xmlns="http://www.tei-c.org/ns/1.0"><head>II.</head><p>The Study Area Kwara State in its entirety is located in the North-Central part of Nigeria. It lies between the Longitude 3 0 and 6 0 E and Latitude 8 0 and 10 0 N respectively (Fig. <ref type="figure" target="#fig_0">1</ref>). It covers an area of over 32,500 square kilometer and bounded by an international boundary with Benin Republic in the West, in the North by Niger, in the East by Kogi and to the south by Oyo, Ekiti and Osun.  The progressive population growth in Ilorin, the nearest major town to the study area, has led to severe shortage of portable drinking water for the area which poses a great challenge to both the citizens and the government. It is therefore obvious that the demand for reliable and consistent water supply is high. Certainly the use of water is beyond mere domestic as virtually all the industries, companies and governmental establishments are in dare need of water. Such high demand can only be achieved through viable boreholes. The drilling of viable boreholes can be obtained by carrying out adequate geophysical studies to empirically ascertain areas or sites where long term steady supply can be achieved.</p><p>Furthermore, rapid industrialization recently witnessed by the Ilorin metropolis has resulted in population increase and has led to the urbanization of satellite villages and settlements of which the ancient Eleko, Kwara Poly. (Permanent site), Ara and Akuo settlements, all of which fall in the study area. The people of these settlements depend solely on surface water from streams and hand dug wells for their domestic use. However, these sources of water are highly vulnerable to pollution thereby making the people to be susceptible to water borne diseases. Moreover, fast increase population growth of this region occasioned by the influx of people from nearly congested city of Ilorin, coupled with the location of government institutions such as Kwara State Polytechnic and University of Ilorin Teaching Hospital has also made these sources of water inadequate for its dwellers, and the need for good quality and readily available portable groundwater in this area forms the basis for this research.</p></div>
<div xmlns="http://www.tei-c.org/ns/1.0"><head>III.</head></div>
<div xmlns="http://www.tei-c.org/ns/1.0"><head>Materials and Methods</head><p>The ABEM WADI VLF-EM Instrument used to measure the EM response is a portable instrument which measures the electrical properties of the subsurface, using EM induction as detailed in <ref type="bibr">McNeil (1980a)</ref>. In this work, thirteen EM profiles were made using a 20m coil spacing, with an expected maximum depth of investigation of about 15m for the horizontal dipole (HD) mode <ref type="bibr">(McNeil, 1983)</ref>. The EM data were collected at 20m interval along thirteen profiles (Fig. <ref type="figure" target="#fig_3">3</ref>) with lengths ranging from 300 to 1700m. The VLF-EM data were presented as profiles figures by plotting raw real (quadrature) measured on the field and the filtered real while their corresponding Karous-Hiljet (K-H) pseudo sections are shown in Figures respectively. The  The VLF WADI instrument displays the filtered real anomaly on the screen, and this anomaly can be roughly interpreted on site. This feature of the instrument is used to select sounding locations for resistivity surveys. For further detailed information of the subsurface, the measured real anomalies were rediscretized at 1 m interval and filtered using the approach of <ref type="bibr">Karous and Hjelt (1983)</ref>. This process yields pseudo-section of relative current density variation with depth. A higher value of relative current density corresponds to conductive subsurface structures.</p><p>IV.</p></div>
<div xmlns="http://www.tei-c.org/ns/1.0"><head>Results and Discussions</head><p>It is observed that apparent current density cross-sections using real and imaginary anomalies show almost similar features. Therefore, for simplicity only the real component results are presented below (Fig. <ref type="figure" target="#fig_5">4</ref>    </p><note type="other">Figure 4a Figure 4b Figure 5a</note><note type="other">Figure 6b</note><p>At location VLF 06 with traverse oriented in the E-W direction, a well-fractured zone with positive Fraser filter was identified (Fig <ref type="figure">9a</ref>). It is located at a horizontal distance between 11-13m, along the profile at depth of between 2-6m. Similar was the case at location VLF 07 with a prominent fracture zone located at a horizontal distance between 28-34m (Fig <ref type="figure" target="#fig_0">10a</ref>), along the profile at depth between 2-6m. At VLF 08 with traverse oriented in the N-S direction, two probable and another two not wellfractured zones were identified. They were located between 5-8m, 32-34m, 50-52m and 68-70m respectively along the profile (Fig <ref type="figure" target="#fig_0">11a</ref>). The depth of each fracture zone was between 0-40m, 0-35m, 0-30m and 0-30m respectively all with orientation sat NE-SW (Fig <ref type="figure" target="#fig_0">11b</ref>).      </p></div>
<div xmlns="http://www.tei-c.org/ns/1.0"><head>Figure 7a</head><note type="other">Figure 7b</note></div>
<div xmlns="http://www.tei-c.org/ns/1.0"><head>Figure 8a</head><note type="other">Figure 8b</note><note type="other">Figure 14b Figure 15a Figure 15b</note></div>
<div xmlns="http://www.tei-c.org/ns/1.0"><head>Figure 16b</head><p>The EM anomalies vary greatly. Some of the anomaly peaks are narrow, sharp while others are broad with varying width extent. The values of the filtered real range from -0.9 to 22.5 across the study area. The profiles for the EM sections contain significant maxima in the filtered real part. Zones with peak positive filtered real anomalies are considered priority areas for electrical sounding, since they often correspond to zones with high conductivity, characteristic of water-filled fractures or faults <ref type="bibr">(Alvin et. al., 1997)</ref>, or effect of appreciable depth to bedrock or lithological variations within the unconsolidated regolith <ref type="bibr">(White et al., 1988)</ref>. In other words, VLF-EM anomalies were delineated as fairlyconductive, conductive, highly-conductive, fairlyresistive and resistive responses at different locations across the study area. Positive anomaly is indicative of steeply-dipping linear features such as fractures. These features serve as channels for migrating fluids and minerals. These points are zones of interest in groundwater abstraction in basement complex terrain. These results therefore form the basis for Vertical Electrical Sounding (VES) investigation that may subesequently be carried out on any portion of the study area.</p><p>V.</p></div>
<div xmlns="http://www.tei-c.org/ns/1.0"><head>Conclusion</head><p>The study area has good prospects for groundwater development due to the presence of fracture zones which are interconnected in nature. Further investigations for groundwater in the study area is therefore recommended; these should however be aimed at searching for fracture zones where overburden is relatively thin and any borehole drilled in the study area should be made to pass through as many fracture zones as possible. Finally, it is recommended that for productive and sustainable boreholes to be drilled on any location in the study area, relevant electrical resistivity methods should be employed for the Vertical Electrical Sounding (VES) of all areas of interests (as suggested by the results of the present study) along each of the thirteen profiles that were traversed.</p></div><figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_0"><head>Figure 1 :</head><label>1</label><figDesc>Figure 1: Merged geographical map of nigeria, kwara state and the study area, herein referred to as kwara polytechnic (source: kwara state bureau of lands, ilorin, 2012) The area of study, falls in Ilorin, the capital city of Kwara State, with Kwara State Polytechnic (Fig. 2) as the central point, lies within the crystalline basement rocks of western part of central Nigeria. The area is a semi-arid region of Nigeria with vegetation mainly guinea savannah, with shrubs and undergrowth (Nwankwo, 2011). The area is drained by rivers and streams such as Oyun River and river Ile-Apa as a tributary of river Niger (Nwankwoet. al., 2004).</figDesc><graphic url="image-2.png" coords="3,109.92,246.04,377.89,378.51" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_1"><head>Figure 2 :</head><label>2</label><figDesc>Figure 2: Guide map of the central point of the study area (kwara state polytechnic, permanent site)</figDesc><graphic url="image-3.png" coords="4,84.26,65.99,429.31,363.53" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_2"><head/><label/><figDesc>interpretation of both the profiles and pseudo sections was basically qualitative or semi quantitative.</figDesc><graphic url="image-4.png" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_3"><head>Figure 3 :</head><label>3</label><figDesc>Figure 3: Location map of the study area showing vlf transverses</figDesc><graphic url="image-5.png" coords="5,91.69,107.66,414.19,371.90" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_4"><head/><label/><figDesc>-Fig 16). At location VLF01 with traverse oriented in the E-W direction, a plot of filtered data shows intermitent positive responses with the most prominet one between 20-30m (Fig 4a) resulting in probable fracture zone located around same region along the profile at a depth extending from 0-6moriented at NW-SE direction (Fig 4b). Year 2019 © 2019 Global Journals Detection of Fracture Zones for Groundwater Investigation from Interpretation of VLF-EM Anomalies of kwara State Polytechnic Ilorin and Its Environs</figDesc><graphic url="image-6.png" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_5"><head>Figure 4</head><label>4</label><figDesc>Figure 4 (a): Filtered in-phase data against distance at location VLF 01 (b): Current density cross section plot inphase data against distance at location VLF 01</figDesc><graphic url="image-7.png" coords="6,139.95,482.73,317.53,214.81" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_6"><head>Figure 6a</head><label>6a</label><figDesc>Figure 6a</figDesc><graphic url="image-8.png" coords="7,100.26,442.71,394.84,252.91" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_7"><head>Figure 5</head><label>5</label><figDesc>Figure 5 (a): Filtered in-phase data against distance at location VLF 02 (b): Current density cross section plot inphase data against distance at location VLF 02</figDesc><graphic url="image-9.png" coords="7,129.63,55.47,337.39,206.99" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_8"><head>Figure 6 Figure 7</head><label>67</label><figDesc>Figure 6 (a): Filtered in-phase data against distance at location VLF 03 (b): Current density cross section plot inphase data against distance at location VLF 03</figDesc><graphic url="image-10.png" coords="8,158.76,55.45,277.60,177.79" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_9"><head>Figure 8</head><label>8</label><figDesc>Figure 8 (a): Filtered in-phase data against distance at location VLF 05 (b): Current density cross section plot inphase data against distance at location VLF 05 At location VLF 09 with traverse oriented E-W direction, a not well-fractured zone with positive Fraser filter was identified (Fig 12a). This zone is located at a horizontal distance between 6-8m, along the profile at depth of between 20-40m (Fig 12b). The result of VLF data collected at location VLF 10 with traverse oriented in E-W direction (Fig 13a) shows two positive fracture Fraser filter responses along the horizontal distance between 7-9m and 16-18m with depth extending from 30-40m for both. They were oriented at NW-SE and NE-SE respectively (Fig 13b). The VLF responses at location VLF 11 with traverse oriented in the E-W direction shows positive responses along the traverse (Fig 14a) resulting in a not pronounced fracture zones located between 0-4m (Fig 14b).</figDesc><graphic url="image-11.png" coords="9,126.66,350.83,341.40,211.60" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_10"><head/><label/><figDesc>Figure 9a</figDesc><graphic url="image-12.png" coords="10,143.95,254.85,307.97,201.98" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_11"><head>Figure 9 Figure 10b Figure 10 Figure 12</head><label>910b1012</label><figDesc>Figure 9 (a): Filtered in-phase data against distance at location VLF 06 (b): Current density cross section plot inphase data against distance at location VLF 06</figDesc><graphic url="image-13.png" coords="10,154.39,520.18,286.92,182.77" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_12"><head>Figure 14a</head><label>14a</label><figDesc>Figure 14a</figDesc><graphic url="image-14.png" coords="13,80.21,394.27,434.77,283.43" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_13"><head>Figure 13 (</head><label>13</label><figDesc>Figure 13 (a): Filtered in-phase data against distance at location VLF 10 (b): Current density cross section plot inphase data against distance at location VLF 10</figDesc><graphic url="image-15.png" coords="13,112.98,55.13,369.28,240.90" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_14"><head>Figure 14 (</head><label>14</label><figDesc>Figure 14 (a): Filtered in-phase data against distance at location VLF 11 (b): Current density cross section plot inphase data against distance at location VLF 11</figDesc><graphic url="image-16.png" coords="14,155.15,304.35,284.68,180.92" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="fig_15"><head>Figure 16a Figure 16</head><label>16a16</label><figDesc>Figure 16a</figDesc><graphic url="image-17.png" coords="15,154.23,61.40,287.24,188.58" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="figure18"><head/><label/><figDesc/><graphic url="image-18.png" coords="11,144.47,55.23,305.64,199.07" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="figure19"><head/><label/><figDesc/><graphic url="image-19.png" coords="11,146.11,506.86,303.13,190.84" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="figure20"><head/><label/><figDesc/><graphic url="image-20.png" coords="12,154.47,67.39,287.34,187.83" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" xml:id="figure21"><head/><label/><figDesc/><graphic url="image-21.png" coords="12,157.31,281.73,280.45,184.65" type="bitmap"/></figure>
<figure xmlns="http://www.tei-c.org/ns/1.0" type="table" xml:id="tab_0"><head/><label/><figDesc>The geological significance of fracture zones in hydrogeology is that it determines the of the underlie rocks(George et al., 2013). Areas that are extensively fractured and where the fractures are deep are considered as weak zones and considered suitable zones for groundwater development (Alagbeet al., 2013);but areas that are slightly fractured and where fractures are not deep are considered as competent zones and are considered better sites for engineering purposes<ref type="bibr" target="#b23">(Sunmonu and Alagbe, 2011)</ref>. In hard rock areas, groundwater is found in the cracks and fractures of the local rock. Groundwater yield depends onthe size of fractures and their interconnectivity.</figDesc><table><row><cell>Detection of Fracture Zones for Groundwater</cell></row><row><cell>Investigation from Interpretation of VLF-EM</cell></row><row><cell>Anomalies of Kwara State Polytechnic Ilorin</cell></row><row><cell>and its Environs</cell></row></table><note>competency</note></figure>
			<note xmlns="http://www.tei-c.org/ns/1.0" place="foot">© 2019 Global Journals © 201</note>
			<note xmlns="http://www.tei-c.org/ns/1.0" place="foot">© 2019 Global Journals</note>
			<note xmlns="http://www.tei-c.org/ns/1.0" place="foot">Year 2019 © 2019 Global Journals © 201</note>
		</body>
		<back>

			<div type="acknowledgement">
<div xmlns="http://www.tei-c.org/ns/1.0"><p>The authors are grateful to the tertiary education trust fund (tetfund) for providing research grant utilised for this study. The authors also wish to acknowledge the support of the management of Kwara State Polytechnic as well as the cooperation of the heads and youths of the communities in which this research was carried out.</p></div>
<div xmlns="http://www.tei-c.org/ns/1.0"><head>Acknowledgements</head></div>
			</div>

			<div type="references">

				<listBibl>

<biblStruct xml:id="b0">
	<monogr>
		<title/>
		<author>
			<persName><forename type="first">K</forename><forename type="middle">A</forename><surname>Adiat</surname></persName>
		</author>
		<imprint/>
	</monogr>
</biblStruct>

<biblStruct xml:id="b1">
	<analytic>
		<title level="a" type="main">Electromagnetic profiling and electrical resistivity soundings in groundwater investigation of a typical basement complex -A case study of Oda town South western Nigeria</title>
		<author>
			<persName><forename type="first">G</forename><surname>Olayanju</surname></persName>
		</author>
		<author>
			<persName><forename type="first">G</forename><surname>Omosuyi</surname></persName>
		</author>
		<author>
			<persName><forename type="first">Ako</forename><forename type="middle">B</forename></persName>
		</author>
	</analytic>
	<monogr>
		<title level="j">Ozean Journal of Social Sciences</title>
		<imprint>
			<biblScope unit="page" from="333" to="363"/>
			<date type="published" when="2009">2009</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b2">
	<analytic>
		<title level="a" type="main">Fracture distribution within Bowen University 3. Permanent site and its hydrogeologic implication</title>
		<author>
			<persName><forename type="first">O</forename><surname>Alagbe</surname></persName>
		</author>
		<author>
			<persName><forename type="first">L</forename><surname>Sunmonu</surname></persName>
		</author>
		<author>
			<persName><forename type="first">M</forename><surname>Adabanija</surname></persName>
		</author>
	</analytic>
	<monogr>
		<title level="j">Res. Journ. of Physical Sciences</title>
		<imprint>
			<biblScope unit="page" from="1" to="5"/>
			<date type="published" when="2013">2013</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b3">
	<analytic>
		<title level="a" type="main">Electromagnetic survey and the search for groundwater in the crystalline basement complex of Nigeria</title>
		<author>
			<persName><forename type="first">U</forename><forename type="middle">M</forename><surname>Amadi</surname></persName>
		</author>
		<author>
			<persName><forename type="first">S</forename><surname>Nurudeen</surname></persName>
		</author>
	</analytic>
	<monogr>
		<title level="j">Journal of Mining Geology</title>
		<imprint>
			<biblScope unit="page" from="45" to="53"/>
			<date type="published" when="1990">1990</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b4">
	<analytic>
		<title/>
		<author>
			<persName><forename type="first">O</forename><surname>Deborah</surname></persName>
		</author>
		<author>
			<persName><forename type="first">O</forename><surname>Ayobami</surname></persName>
		</author>
	</analytic>
	<monogr>
		<title level="j">Adv. in Applied Sci. Res</title>
		<imprint>
			<biblScope unit="page" from="420" to="431"/>
			<date type="published" when="2013">2013</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b5">
	<monogr>
		<title/>
		<author>
			<persName><forename type="first">George</forename><forename type="middle">A</forename></persName>
		</author>
		<imprint/>
	</monogr>
</biblStruct>

<biblStruct xml:id="b6">
	<analytic>
		<title level="a" type="main">Fracture zone detection using very low frequency (VLF) electromagnetic method in parts of Oban Massif, southeastern Nigeria</title>
		<author>
			<persName><forename type="first">A</forename><surname>Abong</surname></persName>
		</author>
		<author>
			<persName><forename type="first">Obi</forename><forename type="middle">D</forename></persName>
		</author>
	</analytic>
	<monogr>
		<title level="j">Advances in Applied Science Research</title>
		<imprint>
			<biblScope unit="page" from="104" to="121"/>
			<date type="published" when="2013">2013</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b7">
	<monogr>
		<title/>
		<author>
			<persName><forename type="first">R</forename><surname>Geurin</surname></persName>
		</author>
		<author>
			<persName><forename type="first">A</forename><surname>Tabbagh</surname></persName>
		</author>
		<author>
			<persName><forename type="first">P</forename><surname>Andrieux</surname></persName>
		</author>
		<imprint>
			<date type="published" when="1994">1994</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b8">
	<monogr>
		<title level="m" type="main">Field and/or resistivity mapping in MT-VLF and implications of data processing; Geophysics</title>
		<imprint>
			<biblScope unit="page" from="1695" to="1712"/>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b9">
	<analytic>
		<title level="a" type="main">Invariants for correcting field polarisation effect in MT-VLF resistivity mapping</title>
		<author>
			<persName><forename type="first">R;</forename><surname>Geurin</surname></persName>
		</author>
		<author>
			<persName><forename type="first">A</forename><surname>Tabbagh</surname></persName>
		</author>
		<author>
			<persName><surname>Benderitter</surname></persName>
		</author>
		<author>
			<persName><forename type="first">P</forename><surname>Andrieux</surname></persName>
		</author>
	</analytic>
	<monogr>
		<title level="j">J. Appl. Geophy; Pp</title>
		<imprint>
			<biblScope unit="page" from="375" to="383"/>
			<date type="published" when="1994">1994</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b10">
	<analytic>
		<title level="a" type="main">Electromagnetic terrain measurement at low induction numbers</title>
		<author>
			<persName><forename type="first">J</forename><surname>Mcneill</surname></persName>
		</author>
	</analytic>
	<monogr>
		<title level="m">Technical Note; Pp. 15Geonics Limited</title>
				<meeting><address><addrLine>Ontario, Canad</addrLine></address></meeting>
		<imprint>
			<date type="published" when="1980">1980</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b11">
	<analytic>
		<title level="a" type="main">The galvanic current component in electromagnetic surveys</title>
		<author>
			<persName><forename type="first">J</forename><surname>Mcneil</surname></persName>
		</author>
	</analytic>
	<monogr>
		<title level="j">Technical Note TN</title>
		<imprint>
			<biblScope unit="volume">17</biblScope>
			<date type="published" when="1985">1985</date>
			<publisher>Geonics Limited</publisher>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b12">
	<monogr>
		<title/>
		<author>
			<persName><forename type="first">J</forename><forename type="middle">D</forename><surname>Mcneill</surname></persName>
		</author>
		<author>
			<persName><forename type="first">Labson</forename><forename type="middle">V F</forename></persName>
		</author>
		<author>
			<persName><forename type="first">In</forename><surname>Nabighian</surname></persName>
		</author>
		<editor>M.C</editor>
		<imprint>
			<date type="published" when="1991">1991</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b13">
	<monogr>
		<title level="m" type="main">of Exploration Geophysicists</title>
		<author>
			<persName><surname>Soc</surname></persName>
		</author>
		<imprint>
			<biblScope unit="page" from="191" to="218"/>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b14">
	<analytic>
		<title level="a" type="main">2D Resistivity Survey for Groundwater Exploration in a Hard Rock Terrain: A Case Study of MAGDAS Observatory, UNILORIN</title>
		<author>
			<persName><forename type="first">L</forename><surname>Nwankwo</surname></persName>
		</author>
	</analytic>
	<monogr>
		<title level="j">Nigeria. Asian Journal of Earth Sciences</title>
		<imprint>
			<biblScope unit="page" from="1" to="3"/>
			<date type="published" when="2011">2011</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b15">
	<monogr>
		<title/>
		<author>
			<persName><forename type="first">L</forename><surname>Nwankwo</surname></persName>
		</author>
		<imprint/>
	</monogr>
</biblStruct>

<biblStruct xml:id="b16">
	<analytic>
		<title level="a" type="main">The use of electrical resistivity pseudosection in elucidating the geology of an East-west profile in the basement complex terrain of Ilorin, West-central</title>
		<author>
			<persName><forename type="first">O</forename><surname>Olasehinde</surname></persName>
		</author>
		<author>
			<persName><forename type="first">E</forename><surname>Babatunde</surname></persName>
		</author>
	</analytic>
	<monogr>
		<title level="j">Nigeria. Nig. J. Pure and Appl. Sci</title>
		<imprint>
			<biblScope unit="page" from="1676" to="1682"/>
			<date type="published" when="2004">2004</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b17">
	<monogr>
		<title level="m" type="main">Interpretation of VLF-EM anomalies of 3D structures by using linear filtering techniques</title>
		<author>
			<persName><forename type="first">D</forename><surname>Mohamed</surname></persName>
		</author>
		<author>
			<persName><forename type="first">A</forename><surname>Haydar</surname></persName>
		</author>
		<author>
			<persName><forename type="first">Alain</forename><forename type="middle">T</forename></persName>
		</author>
		<imprint>
			<date type="published" when="1998">1998</date>
			<biblScope unit="page" from="151" to="163"/>
		</imprint>
	</monogr>
	<note>Annali di geofisica</note>
</biblStruct>

<biblStruct xml:id="b18">
	<analytic>
		<title level="a" type="main">On the scope and limitations of the electromagnetic methods in groundwater prospecting in a Precambrian basement terrain a Nigerian case study</title>
		<author>
			<persName><forename type="first">M</forename><surname>Olorunfemi</surname></persName>
		</author>
		<author>
			<persName><forename type="first">M</forename><surname>O; Dan -Hassan</surname></persName>
		</author>
		<author>
			<persName><forename type="first">A</forename><surname>Ojo</surname></persName>
		</author>
	</analytic>
	<monogr>
		<title level="j">Journal of Africa Earth Sciences</title>
		<imprint>
			<date type="published" when="1995">1995</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b19">
	<monogr>
		<title/>
		<author>
			<persName><forename type="first">K</forename><forename type="middle">O</forename><surname>Ozegin</surname></persName>
		</author>
		<author>
			<persName><forename type="first">A</forename><forename type="middle">O</forename><surname>Oseghale</surname></persName>
		</author>
		<author>
			<persName><forename type="first">E</forename><surname>Ogedegbe</surname></persName>
		</author>
		<imprint>
			<date type="published" when="2012">2012</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b20">
	<analytic>
		<title/>
	</analytic>
	<monogr>
		<title level="j">Adv. in Applied Sci. Res</title>
		<imprint>
			<biblScope unit="page" from="475" to="480"/>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b21">
	<monogr>
		<title level="m" type="main">Electromagnetic prospecting for Groundwater on the Republic of Upper Volta. Geophysical Prospecting</title>
		<author>
			<persName><forename type="first">G</forename><surname>Palacky</surname></persName>
		</author>
		<author>
			<persName><forename type="first">I</forename><surname>Ritsema</surname></persName>
		</author>
		<author>
			<persName><forename type="first">De</forename><surname>Jong</surname></persName>
		</author>
		<author>
			<persName><forename type="first">S</forename></persName>
		</author>
		<imprint>
			<date type="published" when="1981">1981</date>
			<biblScope unit="page" from="932" to="955"/>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b22">
	<analytic>
		<title level="a" type="main">Delineation of groundwater-bearing fracture zones in a hard rock area integrating very low frequency electromagnetic and resistivity data</title>
		<author>
			<persName><forename type="first">S</forename><forename type="middle">P</forename><surname>Sharma</surname></persName>
		</author>
		<author>
			<persName><forename type="first">V</forename><surname>Baranwal</surname></persName>
		</author>
	</analytic>
	<monogr>
		<title level="j">J. of Appl. Geophy. Pp</title>
		<imprint>
			<biblScope unit="page" from="155" to="166"/>
			<date type="published" when="2005">2005</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b23">
	<monogr>
		<title level="m" type="main">Groundmagnetic study to locate buried faults (A case study of abandoned Local Government</title>
		<author>
			<persName><forename type="first">L</forename><surname>Sunmonu</surname></persName>
		</author>
		<author>
			<persName><forename type="first">O</forename><surname>Alagbe</surname></persName>
		</author>
		<imprint>
			<date type="published" when="2011">2011</date>
		</imprint>
	</monogr>
	<note>Secretariat in Ogbomoso</note>
</biblStruct>

<biblStruct xml:id="b24">
	<monogr>
		<title/>
		<author>
			<persName><surname>Intern</surname></persName>
		</author>
		<author>
			<persName><surname>Journ</surname></persName>
		</author>
		<imprint>
			<biblScope unit="page" from="70" to="75"/>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b25">
	<analytic>
		<title level="a" type="main">The response of a threedimensional magnetic and conductive body in shallow depth electromagnetic prospection</title>
		<author>
			<persName><forename type="first">A</forename><surname>Tabbagh</surname></persName>
		</author>
	</analytic>
	<monogr>
		<title level="j">Geophys. J.R. Astron. Soc</title>
		<imprint>
			<biblScope unit="page" from="215" to="230"/>
			<date type="published" when="1985">1985</date>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b26">
	<monogr>
		<title level="m" type="main">Groundwater survey to investigate on the fault pattern of industrial estate</title>
		<author>
			<persName><forename type="first">A</forename><surname>Theophilus</surname></persName>
		</author>
		<author>
			<persName><forename type="first">A</forename><surname>Lukman</surname></persName>
		</author>
		<imprint>
			<date type="published" when="2012">2012</date>
			<pubPlace>Ogbomoso, Southwestern Nigeria</pubPlace>
		</imprint>
	</monogr>
</biblStruct>

<biblStruct xml:id="b27">
	<analytic>
		<title/>
	</analytic>
	<monogr>
		<title level="j">Adv. in Applied Sci. Res</title>
		<imprint>
			<biblScope unit="page" from="3142" to="3149"/>
		</imprint>
	</monogr>
</biblStruct>

				</listBibl>
			</div>
		</back>
	</text>
</TEI>
