GeoScience Enginee ing Vol. 69 (2023), No. 1
geoscience.cz pp. 11–20, ISSN 1802-5420
DOI 10.35180/gse-2023-0085
NON-INVASIVE GEOPHYSICAL INVESTIGATION OF FAILURE
ALONG A SECTION OF AGO-IWOYE MARKET ROAD, AGO-IWOYE,
SOUTHWESTERN NIGERIA
Ganiyu Omo ola MOSURO1 , Oluwaseyi John DADA1, Ola eju Ola unji BAYEWU1 ,
Mo oo Olasunbo OLORUNTOLA2 , Oluwadamila e Oluwa obiloba ODUGBESAN1
1 Olabisi Onabanjo Uni e si y, Depa men o Ea h Sciences, Ogun, Nige ia
2 Uni e si y o Lagos, Depa men o Geosciences, Lagos, Nige ia
E-mail: odugbesanolu[email p o ec ed]
ABSTRACT
A de ailed geophysical in es iga ion was ca ied ou o de e mine i he subsu ace geology is esponsible o he
ailu es along his oad sec ion. This s udy aims o image and iden i y compe en , mode a ely compe en , and
incompe en zones o he subsu ace soil and hus o ind ou i geology is esponsible o he ailu e along his
sec ion o he oad. Elec ical Resis i i y Imaging (ERI) using he Wenne a ay 2D Imaging, and Ve ical
Elec ical Sounding (VES) using he Schlumbe ge a ay we e adop ed o his su ey. The geoelec ic sec ion
om he VES e ealed he p esence o 3 li hological laye s; opsoil, wea he ed laye (clay, sandy clay, clayey
sand), and basemen , which is also ue o he elec ical esis i i y images e ealed by he 2D elec ical esis i i y
imaging. The esul s showed ha he shallow subsu ace benea h he oad sec ion is mos ly unde lain wi h clay
ha is geo echnically incompe en and no sui able o cons uc ion. The causes o oad ailu e a e belie ed o be
he esul o he incompe en clayey opsoil and he wea he ed laye seen in he p o iles, which expand when
abso bing wa e and sh ink when d ying, hus causing ins abili y benea h he pa emen due o he low shea
s eng h and high comp essibili y, and also due o ac u ed basemen ocks a shallow dep hs.
Keywo ds: Basemen ; Clay; Resis i i y; Road ailu e, Subsu ace; Topsoil.
1 INTRODUCTION
Roads a e buil o connec di e en ci ies, owns, and e en communi ies. Road anspo a ion is one o he mos
impo an and mos common modes o anspo a ion in Nige ia oday due o he poo s a e o al e na i e modes
o anspo a ion in he coun y [1]. Road a ic depends on he pa e n o human se lemen s, accoun ing o mo e
han 90 % o he con ibu ion o he sub sec o o he G oss Domes ic P oduc (GDP) [2]. I a oad does no p o ide
i s equi ed use by no ha ing a smoo h su ace o ehicles o mo e on, ha oad ails.
Pa emen ailu e has been a ibu ed o ac o s such as excessi e a ic load o unde es ima ion o a ic olume,
design p oblems such as poo s uc u al design, he use o subs anda d cons uc ion ma e ials o une hical
cons uc ion p ac ices [3]. O he ac o s include inadequa e in o ma ion on he unde lying soil laye s and he local
subsu ace geology [4] exis ence o geological s uc u es such as ac u es and aul s, s eam channels, and shea
zones [5]. This ailu e is no es ic ed o only one geological e ain, as i can occu in bo h he basemen complex
and he sedimen a y e ain.
The geophysics me hod o explo a ion has p o ed qui e ele an in oad and si e in es iga ions and se e al o hese
enginee ing and geological p oblems ha e been success ully sol ed by geophysical me hods [6,7]. Acco ding o
Kamil e al. [8], he e alua ion o exis ing oad s uc u es has a majo po en ial o he applica ion o he elec ical
esis i i y me hod, as he e is an inc easing in e es in main aining and imp o ing he s anda d o se ice o he
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cu en oad ne wo k. Al hough he impo ance o he geophysical me hod in enginee ing geophysics explo a ion
wo k has no been p o ed, i has also been conside ed ha ano he me hod o geoscience explo a ion app oach can
se e as a supplemen o ga he in o ma ion on he condi ion o pa emen dep h and laye hickness, especially o
a long con inuous pa emen assessmen , hus educing he numbe o co ing es s ha can cause damage o he
pa emen s uc u e. A ypical example is he combina ion o he geophysical and geo echnical app oach o
enginee ing p oblems [9,10,11].
Ebhohimen and Mamah [4], who wo ked on he geophysical in es iga ion o oad ailu e in he case o Opoji
Nige ia using elec ical esis i i y, ound ou om he esis i i y da a ha he subsu ace, jus a shallow dep h, was
unde lain wi h clays/shale and sands one, and he pseudo-sec ion was able o show ha he clays domina ed he
uppe pa o he subsu ace and his was esponsible o he c acks and po holes on he oad. Ade emi and Adeola
[12] ca ied ou a geophysical in es iga ion o he causes o oad ailu e along he Abadina communi y oad
Uni e si y o Ibadan, Nige ia, using VES and he ailed segmen o he oad con ained opsoil, clay, a wea he ed
basemen / esh basemen , and ha he ailu e o he oad a ose om he di e en ial se lemen o he subg ade
clay due o high po osi y and e y low pe meabili y ha causes i o swell a e i abso bs wa e .
The pu pose o his s udy is o app ecia e he impo ance o geophysical su eys in iden i ying compe en ,
mode a ely compe en , and incompe en zones, and hence o de e mine whe he he subsu ace geology is
esponsible o he ailu e along his oad sec ion. The objec i es a e o de e mine he esis i i y and hickness o
he subsu ace li hology, o deduce he subsu ace li hology, o classi y he subsu ace li hology in o compe en ,
mode a ely compe en , and incompe en zones, o sugges solu ions o mi iga e oad ailu e along his oad and o
p e en u u e occu ence.
2 LOCATION OF STUDY AREA AND GEOLOGICAL SETTING
The in es iga ed oad is wi hin Ago-Iwoye in sou hwes e n Nige ia (Figu e 1) and lies be ween he longi udes
3°53’60” E o 3°56’6.00” E and he la i udes 6°55’30” N o 6°57’00” N. The oad se es as a link be ween Olabisi
Onabanjo Uni e si y and he main Ago-Iwoye ma ke . A he ime o he s udy, some majo c acks and po holes
can be seen on he oad sec ions, which a e signs o oad ailu e. The s udy a ea is loca ed wi hin he opical
ain o es egion o Wes A ica wi h a clima e cha ac e ized by al e na ing d y and we seasons wi h hea y
ain all, high empe a u e, and humidi y. The mean annual ain all is be ween 1200 and 1500 mm, eaching peaks
in he mon hs o June and July [13]. The we season occu s be ween Ma ch and Oc obe o ea ly No embe . The
d y season is a he sho wi h e y ho days, which begins in la e No embe and con inues un il he end o
Feb ua y. The elie is gen ly ugged, anging om low o high wi h an ele a ion g adien o abou 30 m, and has
a dend i ic d ainage pa e n; su ace wa e low is in he no heas -sou hwes di ec ion.
The P ecamb ian basemen ocks o Sou hwes e n Nige ia a e ound in he Dahomey basin, which consis s o
banded gneisses, migma i e, and g ani e gneisses wi h low-g ade me asedimen a y and me a olcanic schis s uled
by g ani es and cha nocki es o Pan A ican age [14]. Ago-Iwoye is in sou hwes e n Nige ia and con ains some o
hese ocks (Figu e 2). G ani e gneiss and bio i e gneiss a e o en in uded by pegma i e eins and dykes. Olde
g ani e, g anodio i es, and syeni es wi h dole i e dykes also o m pa o he P ecamb ian basemen o Nige ia.
The c ys alline basemen ocks include bio i e-ho nblende gneiss, kyani e gneiss, migma i e gneiss, and g ani es
a e well ac u ed [15].
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Figu e 1. Base map o he s udy a ea showing he oad along which he s udy was ca ied ou
Figu e 2. Geological map o Ago-Iwoye (adap ed om [16])
3 METHODOLOGY
In his s udy, Ve ical Elec ical Sounding and Elec ical Resis i i y Imaging (ERI) we e used o he su ey. The
la e was used o ge he 2D esolu ion o he subsu ace because i p obes e ically downwa d and hen la e ally
along he p o ile while he o me p obes only e ically downwa d, and can show he app oxima e hickness o
he o e bu den seen in he 2D elec ical image go en om he ERI. The ins umen s used o his su ey a e he
Ohmega esis i i y me e , 4 eels o cable and connec ing wi e, 4 elec odes, 4 hamme s, a handy GPS ecei e ,
ield no es and measu ing apes.
The e ical elec ical sounding me hod en ails he es ablishmen o 10 VES poin s o a cu en sp ead (AB/2 =
100 m), while he ield p ocedu e o he 2D imaging su ey en ails he use o he Wenne a ay con igu a ion o
es ablish a o al o 6 p o iles (Figu e 3), 3 o which we e 120 m long and he o he s 100 m in leng h wi h a leng h
o 120 m and 100 m, espec i ely, o a 5-le el measu emen .
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The da a p ocessing o he e ical elec ical sounding me hod was achie ed by plo ing he ob ained esis i i y
alues agains he hal -cu en elec ode spacing (AB/2) on a bi-loga i hm g aph. The ob ained cu e is hen
manually ma ched wi h a Schlumbe ge mas e cu e o delinea e he numbe o laye s and es ima e he
co esponding esis i i y and hickness o he laye s, a e which he geoelec ic pa ame e s we e modeled using
compu e i e a ion on a WinResis p og am o ob ain he geoelec ic pa ame e s o he delinea ed laye s. Simila ly,
he 2D appa en esis i i y da a we e p ocessed and in e ed concu en ly using he RES2DINV in e sion code
[17]. The RES2DINV p og am uses a non-linea op imiza ion echnique ha au oma ically de e mines he in e se
model o he 2D esis i i y dis ibu ion o he subsu ace o he measu ed appa en esis i i y da a [18].
4 RESULTS AND DISCUSSION
4.1 Ve ical Elec ical Sounding (VES) Resul s
The esul s o he VES in e sion p oduced he geoelec ic pa ame e s in he o m o laye esis i i y, dep h,
hickness, and li hology, and a e p esen ed in Table 1 below. The geology o he s udy loca ion, which is a
basemen e ain, aided in he in e ence o he li hology o he s udy a ea o be opsoil, wea he ed ma e ials (clay,
sandy clay, clayey sand, sand), and basemen ock, which helped o classi y he subsu ace in o compe en ,
mode a ely compe en , and incompe en zones. The cu e ypes ob ained in he a ea a e H, HA, and KH, which
means he subsu ace is h ee o ou laye s, he opsoil and wea he ed laye a e composed o clay, sandy clay, and
clayey sand, wi h clay being he p edominan ma e ial while he basemen ock is esh, wea he ed, o ac u ed.
The esis i i y o he opsoil a ies om 17.8 o 197 Ωm and has an a e age hickness o 0.85 m, he wea he ed
laye has a esis i i y ange o 9.3 o 50.1 Ωm, and he basemen ock has a esis i i y ange o 603.3 o 7710.6
Ωm. A summa y o he VES esul s can be seen in Table 1, and a c oss sec ion o he six VES poin s on he p o iles
can also be seen in Figu e 3. I can be seen ha he esis i i y o he opsoil and he wea he ed laye o all he VES
poin s a e <200 Ωm and he oads a e in poo o bad condi ions. VES 1, 3, 4, and 5 ha e opsoil esis i i y alues
be ween 17.8 and 109 Ωm, which co esponds o clay and sandy clay soils which a e incompe en soils ha should
no be used o cons uc ion. While VES 2 and 6 ha e esis i i y alues o 165 and 197 Ωm, which co esponds o
mo e compe en clayey sand, he laye is no hick enough (0.5–1.4 m), and also he wea he ed laye benea h all
he VES poin s is illed wi h clay (9.3–38.9 Ωm), he e y low esis i i y means he conduc i i y is highe , showing
ha he clay con ains a high mois u e con en . This low esis i i y is p oo ha soil is no ideal o enginee ing
cons uc ion due o he absence o d ainage, low shea s eng h, and high comp essibili y. F om li hology (Table
1), i can be in e ed ha clay <100 Ωm is incompe en , sandy clay is mode a ely compe en , clayey sand is
compe en , and he basemen is compe en when no ac u ed and p esen a a shallow dep h.
Figu e 3. Geoelec ic sec ion o VES poin s on p o ile showing dep h, esis i i y and he co ela ion o li hology
along he a e se
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Table 1. Geoelec ic pa ame e s o he Ve ical Elec ical Sounding poin s
VES No
Resis i i y (Ωm)
Thickness (m)
Dep h (m)
Cu e ype
Li hology
1
109.7
0.8
0.8
HA
Topsoil
50.1
5
5.7
Clay
649
13
18.7
Wea he ed basemen
6380
F esh Basemen
2
165
0.6
0.6
H
Topsoil
16
3.7
4.2
Clay
476.5
F esh Basemen
3
27.2
0.8
0.8
H
Topsoil
9.3
6.5
7.3
Clay
7710.6
F esh Basemen
4
90
0.5
0.5
H
Topsoil
22.7
9.5
10
Clay
725.8
Wea he ed basemen
5
17.8
0.8
0.8
H
Topsoil
12.2
9.7
10.4
Clay
603.3
Wea he ed basemen
6
197
1.4
1.4
H
Topsoil
38.7
5.6
7
Clay
6724.3
F esh Basemen
7
97.1
1.1
1.1
HA
Topsoil
31.6
17.8
19
Clay
149.9
27.3
46.2
Sandy Clay
2246.6
F ac u ed Basemen
8
68.4
1.1
1.1
HA
Topsoil
37.4
0.9
2
Clay
101.5
7.5
9.6
Sandy Clay
1782.9
F ac u ed Basemen
9
87.3
0.7
0.7
KH
Topsoil
149.9
1
1.8
Sandy Clay
32.1
6.9
8.7
Clay
7709.4
F esh Basemen
10
91.7
0.7
0.7
KH
Topsoil
184.7
1.8
2.5
Clayey Sand
49.3
6.8
9.2
Clay
1523.1
F esh Basemen
4.2 Elec ical Resis i i y Imaging (ERI) Resul s
The da a we e collec ed in o de o au oma ically gene a e a wo-dimensional 2D esis i i y image o he
subsu ace ha can be e e ed o as he ‘Elec ical Image’. These alues ob ained we e used o he quali a i e
in e p e a ion o he p o iles. The essence o he da a collec ed om hese p o iles was o unde s and he subsu ace
geology in he s udy a ea and o deduce how i a ec s he pa emen abo e i .
In e p e a ion o p o ile 1: bad oad po ion; he elec ical image shows ha he s udy a ea e eals he p esence
o 3 li hological laye s co esponding o he opsoil, he wea he ed laye , and he basemen in VES1 (Figu e 4).
The RMS e o is 4.1 %, and he elec ical image shows shallow o nea -su ace laye s, he esis i i y o which is
be ween 17 o 120 Ωm and a hickness o abou 4.5 m, which shows ha he opsoil down o he wea he ed laye
is clayey o sandy clay. I is qui e simila o VES1 and no compe en o enginee ing cons uc ion because he e
would be a di e en ial se lemen o he sub-base and sub-g ade, which will lead o ailu e. The e a e also low
esis i i y a eas be ween high esis i i y, which is diagnos ic o a shallow ac u e/ aul p esen a he sou he n and
middle pa o he p o ile, which could also ha e con ibu ed o he ailed sec ion.
In e p e a ion o p o ile 2: bad oad condi ion; he elec ical image shows ha he s udy a ea e eals he p esence
o 3 li hological laye s co esponding o he opsoil, he wea he ed laye , and he basemen in VES 2 (Figu e 5).
The elec ical image shows shallow o nea -su ace laye s, he esis i i y o which is be ween 10 and 200 Ωm wi h

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a hickness o abou 7 m, below he e a e laye s wi h highe esis i i y, which means he en i e nea -su ace is
mos ly clayey in na u e, which is no compe en ma e ial o oad pa emen cons uc ion. A po ion o he p o ile
has a esis i i y be ween 10 and 60 Ωm, indica ing a highly sa u a ed zone wi h high mois u e con en , as clay
swells upon abso bing wa e and sh inks on d ying, which is likely esponsible o he po holes seen in his oad
sec ion.
In e p e a ion o p o ile 3: bad oad condi ion; he elec ical image shows ha he s udy a ea e eals he p esence
o 3 li hological laye s co esponding o he opsoil, he wea he ed laye , and he basemen in VES 3 (Figu e 6).
The elec ical image shows shallow o nea -su ace laye s, he esis i i y o which is be ween 9 and 100 Ωm wi h
a hickness o app oxima ely 4.5 m, which means he en i e p o ile is clayey. In he p esence o clay, he
pe meabili y o a geo echnical ma e ial dec eases [19] as i can e ain wa e . The mid- egion o he p o ile has a
esis i i y be ween 10 and 25 Ωm, indica ing a highly sa u a ed zone wi h high mois u e con en . The da kes pa
o he middle po ion is wi hin he wea he ed laye and has a e y low esis i i y o <10 Ωm indica ing a wea he ed
laye o VES 3. This low- esis i i y soil is likely esponsible o he bad s a e o he oad sec ion.
In e p e a ion o p o ile 4: bad oad condi ion; he elec ical image shows ha he s udy a ea e eals he p esence
o 3 li hological laye s co esponding o he opsoil, he wea he ed laye , and he basemen in VES4 (Figu e 7).
The elec ical image shows shallow o nea -su ace laye s, he esis i i y o which is be ween 12 and 100 Ωm wi h
a hickness o abou 5 m, which means he en i e nea -su ace is clayey. The da k blue po ions o he p o ile ha e
esis i i y <30 Ωm, which is a highly sa u a ed zone ha occu s a di e en dep hs along a la e al dis ance o 0 o
100 m o he a e se. I may ha e helped o di e en ially se le he subg ade and hen he subsequen ailu e o
he oad sec ion [20, 21]. The lowe middle po ion is wi hin he wea he ed laye and has a e y low esis i i y
be ween 20 and 30 Ωm, which co esponds o he wea he ed laye o VES4. A la ge po hole was p esen a he
ime o he su ey; o he sec ions o his oad will soon ollow as ehicles con inue o ply he oad.
In e p e a ion o p o ile 5: ai oad condi ion; he elec ical image o his p o ile e eals he p esence o 3
li hological laye s co esponding o he opsoil, he wea he ed laye , and he basemen , as in VES 5 (Figu e 8).
The image shows shallow o nea -su ace laye s, he esis i i y o which is be ween 8 and 200 Ωm wi h a hickness
o abou 10 m, which means he en i e nea -su ace is clayey. The deep blue po ions o he p o ile ha e esis i i y
<50 Ωm, indica ing a highly sa u a ed zone wi h high mois u e con en ha may be esponsible o oad condi ions
because he e is a di e en ial se lemen as ehicles mo e o e hem. Al hough his oad is no as bad as he o he s,
he e a e signs all o e he pa emen ha i will ail soon.
In e p e a ion o p o ile 6: bad oad po ion; he elec ical image shows ha he s udy a ea e eals he p esence
o 3 li hological laye s co esponding o he opsoil, he wea he ed laye , and he basemen in VES 6 (Figu e 9).
The elec ical image shows shallow o nea -su ace laye s, he esis i i y o which is be ween 23 and 250 Ωm and
a hickness o abou 10 m, which shows ha he i s ew me e s a e mos ly clayey wi h a small amoun o clayey
sand. I is no compe en o enginee ing cons uc ion because he e would be di e en ial se lemen o he sub-
base and sub-g ade, which could lead o ailu e and may be esponsible o he bad s a e o he oad sec ion.
Figu e 4. A 2D elec ical esis i i y image o p o ile 1
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Figu e 5. A 2D elec ical esis i i y image o p o ile 2
Figu e 6. A 2D elec ical esis i i y image o p o ile 3
Figu e 7. A 2D elec ical esis i i y image o p o ile 4
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Figu e 8. A 2D elec ical esis i i y image o p o ile 5
Figu e 9. A 2D elec ical esis i i y image o p o ile 6
5 CONCLUSION
A geophysical in es iga ion was ca ied ou using he elec ical esis i i y me hod (2D ERI and VES) o de e mine
whe he he geology benea h he subsu ace is esponsible o he incessan ailu e along a sec ion o he Ago-
Iwoye ma ke oad. The elec ical image and he VES c oss sec ion indica ed ha he subsoil benea h he pa emen
is cha ac e ised by low esis i i y soils as bo h sub-base and sub-g ade and a e hus geo echnically incompe en .
The low- esis i i y soils a e clay, being highly sa u a ed a some loca ions along he a e se, sandy clay, and
clayey sand, which is mo e compe en han he o he s bu was no hick enough whe e p esen .
The esul ob ained a he end o his geophysical su ey has helped o de e mine he esis i i y and hicknesses o
he unde lying laye s a he subsu ace. I aided in in e ing he subsu ace li hology, classi ying hem in o
compe en , mode a ely compe en , o incompe en laye s, and has e ealed ha clay is he p edominan soil in he
opsoil and he wea he ed laye . This clay could swell upon abso bing mois u e (wa e ) and sh ink upon d ying,
hus causing ins abili y benea h he pa emen as ehicles mo e due o he low shea s eng h and high
comp essibili y. Also, he p esence o shallow aul s/ ac u es could be esponsible o he oad ailu e.
The esul o he elec ical esis i i y p obing and imaging wi h he unde s anding o he beha io o ea h’s
subsu ace ma e ials elec ical p ope ies wi h he knowledge o he geology o he s udy a ea esul in he
conclusion ha he ailu e o he oad is due o he unde lying clayey laye .
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REFERENCES
[1] ABAA, S.I. The s uc u e and pe og aphy o alkaline ocks o he Mada Younge G ani e complex, Nige ia.
Jou nal o A ican Ea h Science. 1985, ol. 3(1–2), pp. 107–113. ISSN 0731-7247. DOI: 10.1016/0899-
5362(85)90029-6
[2] NATIONAL BUREAU OF STATISTICS. Annual Abs ac o S a is ics 2016. Vol. 2. Abuja: NBS, 2016.
A ailable a : h ps://www.nige ians a .go .ng/pd uploads/ANNUAL%20ABSTRACT%20VOLUME-2.pd
[3] IFABIYI, I.P. and A.A. KEKERE. Geo echnical In es iga ion o Road Failu e along Ilo in-Ajase – Ipo Road
Kwa a S a e, Nige ia. Jou nal o En i onmen al and Ea h Science. 2013, ol. 3(7), pp. 91–95. ISSN 2225-
0948. A ailable a : h ps://www.iis e.o g/Jou nals/index.php/JEES/a icle/ iew/6367
[4] EBHOHIMEN, V. and L. MAMAH. Geophysical in es iga ion o oad ailu e he case o Opoji in Nige ia.
In e na ional Jou nal o Scien i ic and Enginee ing Resea ch. 2014, ol. 5(1), 1769–1779. ISSN 2229-5518.
A ailable a : h ps://www.ijse .o g/onlineResea chPape Viewe .aspx?Geophysical-in es iga ion-o - oad-
ailu e- he-case-o -Opoji-in-Nige ia.pd
[5] MOMOH, L.O., O. AKINTORINWA and M.O. OLORUNFEMI. Geophysical In es iga ion o Highway
Failu e – a Case S udy om he Basemen Complex Te ain o Sou hwes e n Nige ia. Jou nal o Applied
Sciences Resea ch. 2008, ol. 4(6), 637–648. ISSN 1816-157X. A ailable a :
h p://www.aensiweb.com/old/jas /jas /2008/637-648.pd
[6] NELSON, R.G. and J.H. HAIGH. Geophysical In es iga ions o Skinholes in La e i ic Te ains. In: WARD,
S.H. (ed.). Geo echnical and En i onmen al Geophysics: Volume III, Geo echnical. Tulsa: Socie y o
Explo a ion Geophysicis s, 1990, pp. 133–154. ISBN 978-1-56080-002-6. DOI:
10.1190/1.9781560802785.ch10
[7] ADIAT, K.A.N., A.O. ADELUSI and M.A. AYUK. Rele ance o geophysics in oad ailu es in es iga ion
in a ypical basemen complex o Sou hwes e n Nige ia. The Paci ic Jou nal o Science and Technology.
2009, ol. 10(1), pp. 528–539. ISSN 1551-7624.
[8] KAMIL, A.M, H. AWANG and F.A. IDI. Applica ion o elec ical esis i i y me hod in oad subsu ace
p o iling. In: FATT, N.T. (ed.). P oceedings o he Na ional Geoscience Con e ence 2011: Geoscien is s and
E hics o a Sus ainable Socie y: June 11–12, 2011, Joho Bah u, Joho , Malaysia. Kuala Lumpu :
Geological Socie y o Malaysia, 2011, s. 46. ISBN 978-983-99102-8-5.
[9] OSINOWO, O.O., A.O. AKANJI and A. AKINMOSIN. In eg a ed geophysical and geo echnical
in es iga ion o he ailed po ion o a oad in basemen complex Te ain, Sou hwes Nige ia. RMZ –
Ma e ials and Geoen i onmen . 2011, ol. 58(2), pp. 143–162. ISSN 1854-7400.
[10] OLORUNFEMI, M.O., J.S. OJO, F.A. SONUGA and M.I. OLADAPO. Geophysical in es iga ion o
Ka ka ku ea hdam embankmen . Global Jou nal o Pu e and Applied Sciences. 2000, ol. 6(1), pp. 117–
124. ISSN 1118-0579. DOI: 10.4314/gjpas. 6i1.16087
[11] OZEGIN, K.O., A. OSEGHALE, E.C. OKOLIE and O. UJUANBI. In eg a ion o e y low- equency
elec omagne ic (VLF-EM) and elec ical esis i i y me hods in mapping subsu ace geologic s uc u es
a ou able o oad ailu es. In e na ional Jou nal o Wa e Resou ces and En i onmen al Enginee ing. 2011,
ol. 3(6), pp. 126–131. ISSN 1991-637X. A ailable a :
h ps://academicjou nals.o g/jou nal/IJWREE/a icle- ull- ex -pd /685ECC854735
[12] ADEREMI, F.L. and R.O. ADEOLA. Geophysical in es iga ion o causes o oad ailu e along Abadina
communi y oad, Uni e si y o Ibadan, Nige ia. Jou nal o Resea ch in En i onmen al and Ea h Sciences.
2021, ol. 7(1), pp. 1–5. ISSN 2348-2532. A ailable a : h ps://www.ques jou nals.o g/j ees/pape s/ ol7-
issue1/A07010105.pd
[13] ONAKOMAIYA, S.O., O.O. OYESIKU and J. JEGEDE. Ogun S a e in Maps. Ibadan: Rex Cha les
Publica ion, 1992. ISBN 9789782137364.
[14] OYAWOYE, M.O. The basemen complex o Nige ia. In: DESSAUVAGIE, T.F.J. and A.J. WHITEMAN
(eds.). P oceedings o he Con e ence on A ican Geology: Decembe 7–14, 1970, Uni e si y o Ibadan,
Nige ia. Ibadan: Depa men o Geology, Uni e si y o Ibadan, 1972, pp. 66–102.
[15] EKWUEME, B.N. S uc u al o ien a ions and P ecamb ian de o ma ional episodes o Uwe a ea Oban
massi , SE Nige ia. P ecamb ian Resea ch. 1987, ol. 34(3–4), pp. 269–289. ISSN 1872-7433. DOI:
10.1016/0301-9268(87)90004-0
[16] OMOSANYA, K.O., A.E. AKINBODEWA and G.O. MOSURO. In eg a ed mapping o lineamen s in Ago-
Iwoye SE, SW Nige ia. In e na ional Jou nal o Science and Technology. 2012, ol. 1(2), pp. 68–79. ISSN
2049-7318.