Investigations of Landslide Problem Using Geophysical Techniques around Debresina-Armanja Main Road in Tarmaber Woreda, Northern Shewa Zone, Ethiopia
No Thumbnail Available
Date
2013-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Geophys ical and geo logical in vesti gat ions have been conducted 1'01' land slide problcm
characteri zation of the exist ing main road of the study area. The s ite is located in betlle~n
Debres ina and Armaniya towns. Tarmaber Wereda. north ern Sheila Zone of Amhara Regioll<iI
Stat e. The ma in objecti ve of the study was to image subsuri>lce of the problematic main asphalt
road. identi fy tri ggering mechani sms of land slide problem. and recommend possible mitigation
measures based on the geo-elect ri cal res isti vity stratil·ication of the site and magnetic anomalies
obta ined over the survey area. Geophysical investigations using 2D electrical imaging and
magnetic methods havc been conducted Il)r the land slide problem of the road located HI kebdc'
Dokakitnear Sar Amba Kidan cm hir~tloe al it \ betlleenDebrL' Si na and l\rmania t""lh.
1- 1'0111 the resuhs or the survc). it has been possihk to map thl: ~ Iidillg ;-,tl b:-,u rl ~ ICl: or the g~ologiL'
layers, their ve rti ca l and lateral extents. It has al so been poss ible to map areas 01· lIeaknc\S in the
subsurlace that could be causing and damaging to the lile of the road. According t" the
interpretation of the geophysical result s. the ncar stll·face geolog) of the study area includes
fragmented and di sturbed la ye rs togcth er "ith expansive clay soils which have also conside rab l)
cause of sliding problem over the area. In profile three the cia) so ils are mueh thicker than the
oth er two profil es. In prolile three low res istiv ity deposits are dominant particularl) in the
northeastern side of the survey area. These deposits are may be hugc deposits ol· the fragme nt al
basalt and expansive clay so ils that arc moved down the slope and accllmulated in location " I'
prolile three whic h is jll st do\Vn the road .
Based on the joinl interpretation or the result s. the Slirve) ed area has possi ble slide lone II hich "
characterized by Ij·agmented and structural I) disturbed po rt ion IIhicl! staib rrom "lnhlSt h,&"Cthe
surveyed line to\Vards north cast direc tion . This is interpret ed to be the re'I)(>I"e 01· thL' "'lier
saturated, lIeathercd and fractu red ba sa lt rocK . I·here is also l"nlbliLie "rkcted sllbsurillce tltal
c.\hibib intermedi ate apparent re~istivit) \alue ~ l.'uillprise~ of thl' ~U Ulll\\t: ~t end or 1il(' ~lInc\l' d
proli lcs. This zone consists orsurlitce orllcakncss and some displaced rock units.
As conc ili sion I·j·om the work, the aspha lt road para ll el to the stll·ve) proliles has active slidillg
problem and cracks espec ially at the two ends or the profi les. The clifterent weak zones. deeph
IIcatheri ng cond ition s. ac tion of rain la lL springs and slope nature of th e stlld) arc" lIere the
causi ng lactors l'or this sliding problem. Therel'ore. special alieni ion should be given to maintain
and protect from further sliding problem.
Description
Keywords
Landslide Problem