Assessing the Protective Capacity of Aquifers Using Very-Low-Frequency Electromagnetic Survey

Geosciences

KizitoEjiro Aweto¹  FelixI. Chinyem¹  Oghenero Ohwoghere-Asuma¹  HyacinthO. Nwankwoala² 

[1] Department of Geology, Delta State University, Abraka 330106, Nigeria;Department of Geology, University of Port Harcourt, River State 5323, Nigeria;

关键词: VLF-EM;    filtered imaginary;    filtered real;    protective capacity;    electrical conductivity of clay;   

DOI  :  10.3390/geosciences8050150

来源: DOAJ

【 摘 要 】

The protective capacity of aquifers is a prerequisite for groundwater quality in areas prone to contamination from the ground surface. Aquifers without protective layers are more susceptible to contaminations from point and non-point sources. The protective capacity of an aquifer significantly correlates with the thickness of clay and organic materials that mantled it. To assess aquifer protective capacity, electrical conductivity property of saturated clay was determined from filtered imaginary and real components of Very Low-Frequency Electromagnetic (VLF-EM). The filtered real components against distance and current density pseudo-section produced from real components were concomitantly used for interpretation. Clays capping aquifers were delineated from those without capping from low and high values of filtered imaginary and real components and current density pseudo-section. The distribution of clay laterally across the area indicates that aquifers are poorly protected and susceptible to contaminations from a point and non-point sources. The apparent agreement between inferred geology from VLF-EM interpretation, borehole data and resistivity data underscores the efficacy of VLF-EM as an important tool that can be used or combined with other geophysical methods and borehole information/data for assessment of the protective capacity of the aquifer.

【 授权许可】

Unknown